Opinions on barrel length

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  • Last Post 05 September 2018
Scearcy posted this 11 August 2018

Good morning gents. No data required here - just opinions. I have a Savage Model 12 FTR (I believe). I bought it really cheap and thought I could make some money. Well not so much so it should make a really good test bed for some of the theories being discussed here. For those of you not familiar with this model it has a 30" heavy barrel and the Savage target action. Think of it as sort of over the counter Palma or F class rifle.

Here is my question. It is really muzzle heavy with the 30" barrel. If fact it is so heavy that I don't believe I could shoot it in the CBA Heavy class at a match. I am going to shorten the barrel. My question is what is the optimum length?

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joeb33050 posted this 11 August 2018

LEAVE IT ALONE! If you reach the point where barrel length makes your groups larger, change the barrel.

See http://northlandshooterssupply.com/clearance/

Shilen for <$300, new Savage LV for $205.

We can find a Savage nut near you who'll change the barrel for close to nothing.

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OU812 posted this 11 August 2018

Leave it alone and have it re throated using taper reamer.  It would be very interesting to see what the  factory throat looks like (free bore diameter and length?). 

Longer barrel may require more lube grooves on bullet to hold more lube

What caliber? Is it a 308 Winchester with 1/12 twist? 

Gun may be able to compete Unrestricted class.

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Scearcy posted this 11 August 2018

308 Win I do believe it would be fine in Unrestricted. There was one entered in last years Nationals  and it did poorly which of course may not mean a thing.

 

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Scearcy posted this 11 August 2018

Here is  picture of the throat. the rifle has not had much use as I suspected.

1X12 twist

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frnkeore posted this 11 August 2018

I'm not opposed to shorting the barrel, to fit into Heavy class but, shoot it enough first, to know how accurate it is, as is.

If it will shoot with the Heavy guy's, then shorten it, to make weight. If it won't, you may as well leave it. There isn't much difference in scores, between Heavy and UNR so, you'll place about the same. Maybe higher with less shooters in that class. But, I would also throat it first, as OU812 suggests.

If it isn't competitive, here is what I'd do:

Shorten the chamber end, enough to change the caliber to 30BR. Make sure that the full 30BR throat will be cut and try to get a 1 deg, per side throat (2 deg included angle). That is what holds most of the records. The Egan, MX4-30 ARD bullet matches that angle, too. You can get copy's of it at Accurate Molds.

If the barrel is up to it, it will be competitive, assuming you set it up, with equal prep to the other Heavy's.

Frank

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pat i. posted this 11 August 2018

If I'm seeing what I think I'm seeing why is that land extending all the way to the chamber? Is it the same all the way around when you rotate the bore scope? If not I'd shorten it but from the back and have a new chamber cut. If so get someone to throat the thing right. But maybe I'm seeing something that isn't there.

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Scearcy posted this 11 August 2018

Pat i  

That is a land. You would have to ask Savage why. The picture below is 180 degrees. The end of the chamber is at the right side of the picture. I have two Remingtons like this (223s) that shoot jacketed just fine. I don't know whether to try 100 rounds or simply pull the barrel and rechamber right away.

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pat i. posted this 11 August 2018

The chamber was cut crooked. Might shoot like a house afire if done right. But I wouldn't hold out much hope the way it is.

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Scearcy posted this 11 August 2018

A couple of days ago there was a post (geargnasher I believe) talking about catching bullets. He observed that some of the bullets appeared to have been crushed more deeply into the rifling on one side than the other.

Are we looking at one possible cause? Will the cone shaped side of the throat force an oversized bullet toward the "no throat" side?

I apologize for this threat going sideways but this is more interesting than barrel length.

Jim

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pat i. posted this 11 August 2018

I'd think the land going back to the chamber neck would push the bullet over towards the throated side. Anyway not good no matter what. I've looked at a lot of throats with my bore scope and never saw one like yours. I'd get it fixed. What people should also notice is the rail road track barrels Savage uses. All I've looked at were just like yours but they shoot great. I'd go with a standard 308 chamber again. A Palma chamber would be nice but not cast bullet friendly. Plus it'll be a lot easier to sell in 308 with the standard throat than 30 BR with a long cast bullet throat.

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frnkeore posted this 11 August 2018

The other side of the coin, is that a short chamber can be made longer but, not the other way around.

Frank

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OU812 posted this 12 August 2018

Off center chamber? I thought only Remington did that...not Savage. Maybe buy a new properly inspected barrel? Would this be cheaper than rechambering.

Inspecting a new guns throat before buying can be difficult, because they test fire at the factory. The powder fouling can make thangs difficult to see without cleaning.

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OU812 posted this 12 August 2018

Full length resizing and turning the necks thinner will help center the bullet better AFTER rethroating using a taper reamer. You want the bullet to be pushed back and centered into rifling when chambered.

After cutting my throat using the .310 diameter .75 per side taper reamer.  Jacketed bullets could be seated to fit magazine well and still make contact with rifling. Sierra 168gr Jacketed shoots verywell in my rifle.

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rhbrink posted this 12 August 2018

Go get a good barrel and chamber up in 30 Br and sell the Savage barrel or keep it it isn't that hard to change Savage barrels in case you might want to sell the rifle sometime in the future.Even if you set the barrel back and re-chamber you are probably going to have a 50/50 chance that the savage barrel will shoot with the Custom Heavy Bench guys and just taking up space with the Unlimited guys. By the time you have spent the money to set back and re-chamber might as well spend that money on something that will be competitive. 

Your money and hair! Good Luck

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OU812 posted this 12 August 2018

"I have a Savage Model 12 FTR (I believe). I bought it really cheap and thought I could make some money."

This tells me you will probably swap or sell the rifle. 

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Ken Campbell Iowa posted this 12 August 2018

sadly, i think the chances of a factory savage .... or remmy, winchester, ruger ....   barrel ..... delivering nearly perfect bullets out of the barrel and giving 1/2 minute cast groups is more like 1 in 150  ....   and that is if we ever learn to allow those bullets to survive the trip ...

but closer to 1 in 2 for a factory barrel to give 1.5 moa cast groups ..   and remember :::  you only have to shoot better than the next best guy .... ( g ) ...

ken

 

 

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pat i. posted this 12 August 2018

My advice was based on the assumption of using the rifle as a test bed for the theories being discussed. If you're going to use the gun as a HVY or UNR class match rifle by all means put a good barrel on it. My curiosity would make me see how it shoots with jacketed before and after being rechambered. Another option is to send your pictures to Savage with a note and see if they'll give you a new barrel.

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Scearcy posted this 12 August 2018

You know Pat i, I like both of your suggestions. First a brief story: Many years ago I bought  Mossberg target 22 Lr. It did not shoot well. A friend said send it back to Mossberg. I responded that no one stands behind their products. He bought the rifle from me for a song, sent it back, and they sent him a brand new rifle. He never shot it but he showed it to me many times.

There is no way I can take that barrel off without shooting it. I am thinking both jacketed and cast. Why not? I will probably learn something.

Since this rifle has the target action, I believe the standard Savage thread size will not fit. Can anyone confirm that? 

Both of my normal gun smiths have had serious surgery this summer. One in particular will do a rechamber job very inexpensively as long as it is a standard chamber. He has gotten quite independent since his heart surgery, however. Go figure.

Jim

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Geargnasher posted this 12 August 2018

Jim, please shoot it some before you change anything. That is one of the worst examples I have ever seen of throat being off-center relative to the bore. Typically even the bad ones will have grooves cut out at the throat entrance, but yours appears to not have been touched by the reamer on one side.

Jacketed first to smooth up things, then cast. My prediction is 3 moa at best with cast bullets.

Regarding my comments about recovering bullets that did not group well and had longer engraving marks on one side than the other, in all cases those were fired from known-good chambers. I have not trapped or examined bullets fired from known-eccentric throats.

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Ken Campbell Iowa posted this 12 August 2018

i bot a 40XBR 22 rimfire... factory stainless heavy barrel, mcmillen stock, jewell trigger  ... used, the owner said it shot real well.  it did shoot real well, for a squirrel rifle .. about 1 moa .....   the bullets showed off-center rifling... ie off-center chambering ....  so i set it back and rechambered it concentrically ... it then shot about half-minute.  ( later i put a douglas match barrel on it and it shot even better ( 52 winchester type reamer ) ...  naturally i sold it and it did exceedingly well for it's new owner. )

anyway, my vote is that concentric chambers shoot better .   the 40x comes from the remmy custom shop so i was "" surprised "" that the chamber was cut off-center.  

for trivia, the reason chambers are cut off center more than you would like .... is that the rifling is often not centered with the outside of the barrel ... the drill hole wanders around as it proceeds down the barrel  .... and since the barrel is held by essentially lathe jaws on it's outside during factory speed chambering  ...  the chamber reamer is occasionally plunged a little sideways into the curly hole.    precision gunsmiths spend a lot of time to position the hole concentric with the barrel at the throat when they cut a chamber ... not a simple thing , and makes for great debate amongst gunsmiths.

so, jim, .............. all we fans are awaiting your before-and-after report .

ken

 

 

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Scearcy posted this 12 August 2018

I followed Joeb's link to the clearance barrels. There are some shilens but they are all small shank. I may still buy one since I have a savage small shank donor rifle in the back of the gun safe also.

The supplier did have a number of new large shank Savage take offs. There are no 308s but there was a 243. I do have a 243 fetish. The problem is the chamber may have the same problem as the barrel I have now.

It will be a month before I get back to this rifle I think.

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pat i. posted this 13 August 2018

Just remember that Mossberg before you start throwing money around. Can't hurt to ask.

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RicinYakima posted this 13 August 2018

Ken's story on the .22 40X is why you pay a good gunsmith $250 to chamber your $400 barrel blank. It takes him four hours to center the bore, on pilots not the outside, and cut a chamber.

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John Alexander posted this 13 August 2018

My last Savage 12-bvss, 223 had a throat just like yours with one land going all the way back. It shot match jacketed bullets into the usual 0.7-.8" for five shot groups as my other Savages (Maybe that's as well as I can shoot.). I decided life was too short to try cast and donated it for a raffle. It has probably killed a lot of innocent rodents by now.

John

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JSH posted this 13 August 2018

Lapua Brass Sierra 155 Palma 1 grain over book max of Varget Twist is 1-11 I believe. I have the same rifle. Some will po po them. Mine makes me happy and can make some 6.5 guys shut their mouth. I also have a LRP 223. Box stock rifle compared to a build. You will spend a fair bit more to build an equal, for jacketed.

As mentioned above, I would just barrel it and be done myself for cast use.

Bore scopes. Now I am all for tools in the tool box and the right tool for the job. Years past we had a good barrel or we didn't. Today with a bore scope we can see so many things to worry about. What did we do before we had these things to worry and fret about. Jeff

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Scearcy posted this 14 August 2018

I spoke to Savage yesterday. Their warranty is very clear and not at all unreasonable: original owner and within 1 year of purchase. I satisfy neither of these criteria. Now the young lady invited me to send the rifle, not just the barrel, in to their shop. Again not unreasonable. Her commitment was that they would look at it and see if it was a "problem" and a defect caused by workmanship. They will be happy to replace the barrel but there was nothing approaching a commitment to doing it for free if the problem was as I described.

None of this is surprising or unreasonable but the burden of proof and the financial commitment are mine for a rifle no longer under warranty. I am making a 300 mile drive today so I will have ample time to consider my options.

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pat i. posted this 14 August 2018

That's a tough call on what to do. In the long run it would probably still be cheaper than buying and fitting a custom barrel and HOPEFULLY they'd make sure you got a good one to make sure you were happy. I can't see themclaiming that wasn't a manufacturing defect and I've read articles of people that love to buy refurbished items because they've been gone through and all the little defects fixed. Keep us informed.

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BudHyett posted this 15 August 2018

Ed Doonan and I built a bullet-catching box that worked well for cast and all jacketed bullets except varmint jackets. A person could see cast bullet marking showing a slightly off-center start self-correcting as it went down the barrel. The extreme off-center start bullets did not correct and showed skid-marks all the way to the target.

The extreme other way example was a chamber with a Lyman 457122 bullet fit under size (.458) in a ,45-70 Marlin Micro-groove. This bullet went down the barrel sideways and was still not a flyer. The bullet was sideways in the chamber and stayed that way down the barrel. 

I think this chamber would be an extreme off-center start condition. If you want to keep the barrel, shorten the chamber end and cut a minimum .308 factory chamber with custom leade.

Send Savage the barrel and action only if you have had any custom work to the stock. Alice wore out the barrel on her .308 12BVSS (at least 12,000 rounds) and we had Savage barrel to keep it in Production class. Alice's stock had been fitted to her and I did not want to lose the work if that stock was misplaced. They sent the rifle back in a Savage laminated thumb-hole varmint stock after testing.

I guess I will need to buy a Savage benchrest action and build another .220 Swift to utilize the windfall. 

 

Country boy from Illinois, living in the Magical Pacific Northwest

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pat i. posted this 15 August 2018

Hell I've got some old Savage parts laying around here somewhere. Maybe Ill send them a broken extractor and hope they send me back a rifle around it.

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Scearcy posted this 16 August 2018

My old gun smith pal is not in good health. That means more cost and less fun to have someone else rechamber that barrel. There is ample time to return the rifle to Savage. Perhaps it would be an interesting look at their customer service.

Jim

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Ken Campbell Iowa posted this 16 August 2018

jim ... you could drop it off on your way to the nats ... you drive right by my house ...  almost ....   but then you need to decide what you want to do to it ...     maybe we could squeeze it down to a 243 winchester AI  ...  or 6br ...  ?? 

ken

 

 

 

 

   

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Scearcy posted this 19 August 2018

Ken

Thank you fro the offer. My other terribly important priorities are going to trump the Nationals this year so I won't be taking a leisurely drive through Iowa.  The second gunsmith I use is taking a 2,000 mile motorcycle trip so I believe this means he is able to rechamber a barrel when he returns. The cost is not prohibitive so the decision is likely made.

I do intend to to shoot 50-60 rounds through the bad chamber first but plans don't always translate to action.

Jim

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Ken Campbell Iowa posted this 20 August 2018

my friend john g. uses a gunsmith in south central Minn., ... says he is very particular, so that is a start.  i am wary when a gunny tells me he chambers a match rifle in 45 minutes ...   btw, you can do a great chambering job by hand, it just takes a few hours.  anyway if you are interested i will get his address .

ken

 

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Scearcy posted this 28 August 2018

Eventually I decided to just rechamber the existing factory barrel. Once the barrel was off the rifle, the gundoc did a chamber cast. You could clearly see that the chamber and bore were out of alignment - with the naked eye. The Doc said it was the worst misalignment he had seen. Once the old chamber was cut away (we removed 3" plus from the barrel) the bores runout compared to the barrels exterior measured .018. Once again clearly visible as the barrel turned in the lathe.

Now the barrel has a nice fresh standard chamber. I am anxious to see how the barrel will shoot. 

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pat i. posted this 28 August 2018

That's great Jim. Keep us up to date. Did you leave it a standard.308? Any special throating?

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Scearcy posted this 28 August 2018

Pat,

Standard 308 chamber. Throat measures exactly .312. The length of the throat is .150 to the beginning of the lands. Alignment is perfect as one would expect when Doc does the work. The rifle should shoot. We will see soon enough.

Jim

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Scearcy posted this 28 August 2018

I am going to return the barrel stub to Savage. I don't know if they will ever look at it but they might.

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pat i. posted this 29 August 2018

Good idea about returning the stub. Hopefully they'll look at it and maybe make some changes. A chamber like that has no place on a $1200 gun. Sounds like you're gonna have a nice test bed for all the stuff Joe brings up.

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Scearcy posted this 30 August 2018

This post is the last post I intend to do about this rifle that does not involve a cast bullet accuracy test. I did however want to do the Joeb test first just to see how capable this rifle might be now that it have a new chamber. My load was a 150 gr Sierra boat tail pushed by 18 gr of 4759.

My first shot was at 25 yards to get on paper. Then #2 was a check to make sure at 100 yards. This is the shot out of the bottom group. I then shot #3 - #10 with more care while I let the rifle settle down. They are the bottom group. Shots 3 and 4 ( the first 2 shots) are the two widest. After that everything grouped well. The top group is shots #11 - #15. This group measures .316".

All is well with the new chamber. 

I have been watching the Taper Bump thread closely. This rifle is not throated but I do have a mold for one of Frank's bullets.  Hmmm?

Jim

 

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Scearcy posted this 30 August 2018

The picture:

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pat i. posted this 31 August 2018

Great results Jim. I wouldn't be able to do anything with that gun until I saw how it shot with some Sierra 155 Palma and 168 Matchkings with full power loads. It might be a barn burner.

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Scearcy posted this 31 August 2018

Pat i

The bullets are match bullets but there has to be a better powder than 4759.

On the other hand, maybe that rifle will shoot 170 gr cast spitzers into 1/2 MOA. One of the first things I want to try is a 3" bench rest adapter for the Anschutz accessory rail.

Thanks for you constructive input during this exploration.

Jim

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OU812 posted this 31 August 2018

Bumping a none tapered , long bearing surface bullet to match tapered reamer and throat works well. Remember the LBT bullet designs with long bearing surface that required you cutting freebore longer.

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Scearcy posted this 31 August 2018

I have had really good results with a bumped bullet in a factory chamber also. I couldn't tell you why. I have owned three throated rifles and was never really impressed with any of them. Again maybe luck of the draw. In the early years I shot a cheap Savage heavy barrel with LBT bullets that I bought. I didn't even own a mold. I beat some good shooters with that combo so I like LBT bullets. I seated them deep.

Different experiences is why we argue in this forum.

Jim

 

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OU812 posted this 31 August 2018

Your .312 diameter free bore seems large...are you sure? Sometimes chamber cast can be inaccurate.

Swaging down an oversize bore rider (314299) may work. You must try the Felix lube also.

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Scearcy posted this 31 August 2018

You know, I thought .312 seemed large too but two of us measured the casting with two different micrometers. Since the casting was cerosafe we took the measurements several times over about a one hour period. I will do a slip fit ink test today

I m very intrigued by the Felix lube. I have 3 different single diameter bullets on hand so that is where I am going to start with bullets. Next on the list I have about 500 unsized NOE 311299s on hand. This should be fun. I do believe I am going to standardize on the 18 gr load of 4759 just to keep this manageable initially.

Jim

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Scearcy posted this 02 September 2018

I have been shooting some cast bullets the last 3 days. The 1st 50 rounds were comprised of 3 bullets I already had at hand: RCBS 165 Sil, RCBS 180 SP and Accurate 31-200N. None of them really fit well although with a little taper, the 180 SP would be fine. The average for these 10 groups was .856"

 I took a 243 to the range today but I did load up 10 unknown bullets for the 308 also. Let me be clear that I don't expect to repeat that second group very often. I don't even know which bullet this is. Someone obviously gave them to me the year I was shooting the CZ 308 and for whatever reason I didn't shoot them all. For obvious reasons I need to identify the mold. HELP FRANK! Anyone? I am pretty sure it is one of Franks. It weighs 163 gr and is less than an inch long with the check. It really doesn't look like any of the pictures on the NOE website, however. 

Anyhow the average of the two groups is .526".

Jim

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pat i. posted this 02 September 2018

It looks LBT to me. Is the nose tapered?

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Scearcy posted this 02 September 2018

Pat i

Yes it is tapered and it is entirely possible for this to be an LBT. I have a friend who owns several LBT molds and he often tries out bullets on the rest of us. I thought most of Veral's molds were not tapered?

Jim

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frnkeore posted this 03 September 2018

Jim,

It doesn't look like any of mine.

Frank

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Scearcy posted this 03 September 2018

The length of the ogive is .341 which is exactly right for the LBT. The OAL is midway between the catalogued length of the 140 gr and 160 gr. It sure looks right. Now can I get one purchased.

Jim

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pat i. posted this 03 September 2018

I don't think Veral cuts molds for tapered bullets. If it is an LBT it must have tapered after it was cast.

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OU812 posted this 03 September 2018

What? Veral has cut lots of molds for tapered bullets.

Tapering or swaging a non tapered design works very well for me.

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pat i. posted this 03 September 2018

I checked and you're absolutely right Keith. I've ordered and owned a boat load of LBT molds and never knew he'd cut a tapered mold until now. I guess along with starting to read directions I better start fully reading catalogs.

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Scearcy posted this 03 September 2018

Good morning!

The gent that gave me these used to own his own bullet casting business. I am going to try to reach him and order 500 more. Pat if I succeed would you like to try some? Keith I couldn't agree with you more about some tapering. On a couple of occasions I have had very good success tapering bullets for 308s with standard chambers. Done judiciously it allows flexibility to tune the fit.

Jim

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pat i. posted this 03 September 2018

Thanks for the offer Jim but I have dies for any tapering I need to do.

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Scearcy posted this 03 September 2018

Oops - my guy didn't make this either. He is also of the opinion that 4 shallow lube grooves means it is not an LBT. Boy do I feel stupid. Sometimes I don't even remember when my memory was good.

The search goes on.

Jim

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pat i. posted this 03 September 2018

I'm still thinking LBT. 4 shallow grooves don't take it out of the equation. I don't know about now but number and depth of grooves was a choice. Any chance you got those from Dick Reese?

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Scearcy posted this 03 September 2018

I can't see much chance of it being anything else but LBT. No one else catalogues anything similar that I can find. I have reached out to the only other guys I know who use LBT molds. It could be tomorrow before I hear from them.

No this was after Dick's time. He was my mentor in all things cast while he was with us. His rifle disappeared. I have never seen it again. 

I reached out to a custom mold maker to see if they would do this type of project. They are quite responsive so I expect to hear from them tomorrow. I am concerned that it might be very difficult to get this mold on Verals to do list. 

Jim

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pat i. posted this 03 September 2018

Dick was a great guy and we had a lot of cast bullet talks. Its a shame losing guys like him, Ed Doonan and Norm Duesterhoeft. I met a lot of great people playing this game. What about Gerry Barnes? Another guy I liked being around.

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Scearcy posted this 03 September 2018

I am sorry to say Gerry is gone too. He died not long after Dick. Sam Wosmek is still kicking. He shot the Regional when he was 90 years old. We have a good group of guys now but we can't shoot like that bunch could.

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pat i. posted this 03 September 2018

Sorry to hear about Gerry he was a great guy. I was the Director of Registered Competition at the time those guys were all shooting and while it had nothing to do with me I still feel it was the high water mark of the CBA match program up to this point. A lot of experimenting. A lot of really good shooters. And a lot of laughing. I was up to Minnetonka a few times and always left smiling. Better get back to cast bullet stuff because talking about losing all those guys is depressing and making me feel old.

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Scearcy posted this 04 September 2018

I hear you, Pat.

Jim

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Brodie posted this 04 September 2018

 Yes it can be depressing.  It helps to remember all the good times you had with those and other people who have passed on.

B.E.Brickey

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pat i. posted this 04 September 2018

Great advice Brodie. Every once in a while a name will pop into my head and put a smile on my face. Maybe it's age or internet or modern life in general but it seems things were a lot more fun back then. I don't remember people being so serious about something that's supposed to be a hobby or lacking a healthy dose of humor. 

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Larry Gibson posted this 04 September 2018

Scearcy

Your bullet appears to be the 30 XCB (NOE 310-165-FN).  The short radius ogive and multiple shallow lube grooves are my input into the design. It has proven to be an excellent design and is extremely accurate at various velocity levels.

LMG

Concealment is not cover.........

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Scearcy posted this 04 September 2018

Larry

Thank you. I figured that out last night when I found out who had supplied my sample  bullets. I have already ordered a mold this morning. The picture on the NOE site is a bit inaccurate but all is good.

I am going to test that bullet as well as a couple of others in 3-4 rifles over the coming months. Now that I know I can soon make more, I can shoot up my current supply.

Jim

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OU812 posted this 04 September 2018

I have this mould and is probably my easiest mould to cast with. Bullets fall from mould very easily. NOE has made improvements such as elimenating raised parting vent line on tip of bullet.

BTW...what is the as cast angle of tapered section.

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Scearcy posted this 04 September 2018

It appears to me that there are two distinct sections that are angled differently from each other. I do not have my own mold yet so that is about ll I can tell you. Dust off your trigonometry and calculate the angle from NOEs schematic. That should be close.

Jim

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Ken Campbell Iowa posted this 04 September 2018

1 degree gives about 0.035 diameter difference per inch.  so if over a quarter inch 1 degree per side gives about 0.008-0.009 thou diameter difference.    normal chamber nomenclature refers to taper per side.

btw it takes a half degree per side taper to engrave a half inch of bullet BEFORE IT IS FIRED without smunching the bullet with a hammer ... so to speak.

note:  if you have a 1/4 degree throat ... you can engrave the full 1 inch of your bullet with little pressure BEFORE FIRING ...  is that breech seating ??  oh my golly ... could it be that easy ??  maybe the CBA R&D team should play with that .

see what i did there ??

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Scearcy posted this 04 September 2018

Ken based on your numbers I believe the bullet tapers at 1 1/2 degree per side - same as a factory 308

Jim

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OU812 posted this 04 September 2018

Length from .300 bore diameter to .3125 bearing surface is about .207" long...so taper is steeper than 1 degree. 

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45 2.1 posted this 04 September 2018

Length from .300 bore diameter to .3125 bearing surface is about .207" long...so taper is steeper than 1 degree. 

 

A little under 1.75 degrees per side.................. actual (per your dimensions) is 1 degree 43 minutes 46 seconds rounded to nearest second.

 

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Scearcy posted this 05 September 2018

The taper is .011 inch in diameter over .221" in length according to NOE. Who has the math?

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45 2.1 posted this 05 September 2018

The taper is .011 inch in diameter over .221" in length according to NOE. Who has the math?

1.425618791 degrees per side = 1 degree 25 minutes 32 seconds approx. per side

 

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frnkeore posted this 05 September 2018

Sounds like they were trying to match the '06 throat at, 1.3713 deg, per side.

Frank

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Scearcy posted this 05 September 2018

Gentlemen

This thread has drifted far afield. I apologize. But thanks to the GunDoc, a meaningful trip down memory lane, and everyones help with the mystery bullet, I had a great time.

After a lengthy affair with the 243, I intend to spend the next few months shooting new bullets through some long neglected 308s. I am not promising to further cast bullet science one single millimeter but I will share my experiences as I go. I should mention I have ordered a taper die from Mountain Molds as was recommended in this thread. I will shoot a lot of before and after being tapered groups. Perhaps that will answer some questions that have been posed lately.

Jim

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Larry Gibson posted this 05 September 2018

Frank is correct.  The bullet was designed to fit the throat of a 30-06 XCB reamer which has been used to chamber numerous rifles for 30 XCB (30x57), 30x60 XCB and the 30-06 XCB cartridges.  The bullet was designed to match the reamer's throat.  I do believe the reamer's throat was angled for cast bullets though I don't recall the specifics.  Goodsteel had the reamer made and has done the chambering so a check with him should get the exact information.

As to the 30 XCB design.  I have shot mine now in numerous factory and milsurp .308Ws and 30-06s, in my own 308 CBC and in the 30-30 cartridge in a 21" Contender barrel.  In every case exceptional cast bullet accuracy for each rifle was easily obtained and consistent regardless of the leade taper, type of rifling, etc.  The 30 XCB design has prove to be an exceptionally accurate cast bullet in my M70 .308W target rifle and my M1903A1 National Match rifle.  The M70 Target has a factory (Winchester) chamber/throat/leade and the M1903A1 NM chamber was finish reamed with a reamer made for M72 ammunition.

On a lark I also tried it in my 10" Contender 32 H&R and was surprised by the accuracy even though the velocity left a bit to be desired.

LMG 

Concealment is not cover.........

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