.308x1.6125

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  • Last Post 30 September 2018
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Ross Smith posted this 20 September 2018

I bought the John Ardito rifle that was advertised here. I'm looking forward to a learning experience, probably a long one given my history.

The rifle came with several formed 308 brass, winchester, that are 1.61+ long so not standard 30 br????????? Searching this site it looks like 21-24 grn Rl-7 was his load????????/ and it was plenty hot. What might be a good starting point, 18 grn rl7, lyman #2 alloy, or harder? The rifle came with 2 Eagan molds,tapered bore rider style. One longer than the other 1.013" and 1.15" I think. The fired cases all chamber easily and if a bullet is finger seated in a case , it goes so far and stops. When that is chambered it has a slight resistance when closing the bolt. When extracting the case, the cast bullet will be seated a shade deeper and there is chamfering around the driving band. Did not see and rifling marks. The brass were all formed from trimmed and sized 308 brass.

Any advice is welcome on loads, brass forming, dies, good dogs , etc . post on the thread or pm me.

Thanks , Ross

 

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frnkeore posted this 21 September 2018

Is the extra length in the shoulder or the neck?

Frank

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Ross Smith posted this 21 September 2018

Best I can:

6mm br= 1.075 to the shoulder

mine 1.145"

Some of the case are longer 1.618" and that is in the neck. They still chamber. Most of the cases are not trimmed to the same length. Judging from the bullet that I seated with the bolt, there is a long lead. I have not chamber cast yet, maybe tonight.

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MarkinEllensburg posted this 21 September 2018

There is no standard .30BR. I've read that the outside case dimensions of .30BR = .308x1.5" Inside might be different as the .30BR is generally formed from a Norma 6mm BR. However some are forming the case from a whole host of other parent cartridges. Some believe that large primers are better, some claim primer size does not matter. To make a form die shorten a .308 sizer, remove the decap stem and ream the top of the die to neck diameter, however this might make cases with necks that are too large in OD. It might be best to have one made from the reamer that cut the chamber but with a second hand wildcat you get what you get.

For a load starting point if you can find match data from that rifle it might be worthwhile to copy it as to alloy, primer, powder and charge. If you want a starting load reduce the max you can find by 10%. When I inherited my .30BR it did not come with load data. I first looked at match data in TFS and tried what seemed to be popular. I meanwhile kept researching and finally discovered that my Father was last using Varget in the rifle. I promptly made the switch and accuracy improved. A year ago I made a chamber cast. It took me a year to actually study that cast and understand what it meant: my throat has long since been shot out/eroded. I'm now contemplating reaming it out to .308x1.8" and if I do I know load work up will be all experimentation, no data source known. 

Frank asks a great question. Can you post a pic of the case and perhaps a chamber cast?

 

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rmrix posted this 21 September 2018

I bought the John Ardito rifle that was advertised here. I'm looking forward to a learning experience, probably a long one given my history.

The rifle came with several formed 308 brass, winchester, that are 1.61+ long so not standard 30 br????????? Searching this site it looks like 21-24 grn Rl-7 was his load????????/ and it was plenty hot. The brass were all formed from trimmed and sized 308 brass.

Any advice is welcome on loads, brass forming, dies, good dogs , etc . post on the thread or pm me.

Thanks , Ross"

 

If you have one of John's rifles and it is chambered like the one he built for me, it is NOT based on the 30 BR.

 

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pat i. posted this 21 September 2018

I don't know what chamber Ardito used but from what you're saying about the cases its probably 308 x 1 5/8 or that would be my guess. I chambered a gun up in 30x47. I made cases by shortening a 308 die and using 300 Savage brass. That's probably what you're going to end up doing unless you can get a hold of his forming die. Depending on what he did you might end up having to turn the necks. What diameter is the neck on the cases you have with a bullet seated? What diameter is the web on the cases you have? I might be all wet here so doing or having someone do a chamber cast would be a pretty good idea. My best guess though is that he ran a .308 reamer in short.

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rmrix posted this 21 September 2018

" My best guess though is that he ran a .308 reamer in short."

 

Nope.

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Ross Smith posted this 21 September 2018

I did a chamber cast. And this cat is not a 30br by a long shot. The case taper is close to a 30-06 taper, not a 308 case taper! It has a 30 degree shoulder. So it's a 30 x 1.6125 and is it's own animal. Most of the cases are sized but not trimmed or neck reamed, or fire formed. Lots of fiddling ahead. Going to eventually need case trimmer and form dies. 

The cases that have been used have a .312+ inside neck and a .308 shoulder at the base. My guess is that an inside neck reamer was used and stopped short of going all the way down the neck. Bullets are slip fit and stop on the base, they are then final seated in the throat when closing the bolt.

Notes on the baggies that all came in said 308 cases are better than 30-06 cases, I assume form forming. Gonna need a custom sizing die.

Starting load, anybody???????   18grns. R-7??????????  John's load was 24. I only shoot 20grns r7 in my '06.

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frnkeore posted this 21 September 2018

Check your shoulder dimensions, against this 300 savage drawing.

A CBA record holder, in the late 80's, early '90's (Etz Johnson) shot what he called a 1 5/8", long necked, Savage.. Short chambered, with a extended neck. I think his neck was 3/8 long.

The 300 Savage is a excellent cartridge design. I had a 722 Rem and had a Palma neck and throat reamer made to extend the OA case length to 2.03, so that I could shoot full length 308 Win cases.

I've always liked the 30 deg shoulder.

Frank

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pat i. posted this 21 September 2018

" My best guess though is that he ran a .308 reamer in short."

 

Nope.

Since you seem to know what it isn't why not just tell what it is.

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porthos posted this 21 September 2018

i have a Ardito rifle that he built for me in 1992. i shot it for appx 150 rounds. i then went back to trapshooting  for the next 23 years. so, i didn't  shoot it much. mine came with a forming die for  the brass, an Egan mold, RCBS rockchucker press and a bullet " forming " die. the bullet die was cut with the same reamer that he throated the chamber with. the press has linkage that ejects the bullet after forming. with the letter he sent me after load testing; he states that the best loads are 24-26 gr. of RL-7  and 27-28 gr. of H332. the bullet weights 195 gr. he sent some groups with the letter. 24 gr RL-7 group is11/16.  with H332 3 groups  1/2, 1/2 and 5/8. all 5 shots. maybe some day i may get back to shooting it some more

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Ross Smith posted this 21 September 2018

Frank: Right at the start of the shoulder this critter is +- .455 , not the    same as your schematic. the extra length over the 30-1.5 is the body and neck. Hard to tell exactly as all cases are not trimmed equal. Also this dates back to 1992. The taper of the body is different from a 308 and closer too but not the same as an '06. It's not a 30 br and not a 30-1 5/8. It's an Ardito, probably just like RMRIX's.

Any way I have 25 yrs worth of dust etc cleaned up, the molds tuned up, the brass in the tumbler, and lead heating. Thanks all, I think this is enough info to get me started, more to follow after it happens. Ross

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frnkeore posted this 21 September 2018

Sounds like it is, very different than the 30 BR!

At your convenience, could you give us the internal, water weight capacity of it?

I look forward to your results, in getting it tuned up.

Thank you,

Frank

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Ross Smith posted this 22 September 2018

ps-  ya'all been very helpful. Even errant leads gave me an answer!

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Lee Wiggins posted this 22 September 2018

Ross,

Your rifle is probably a 1 in 14 twist Hart stainless barrel chambered 308x1.625 with a tapered throat of 1/2 degree per side ( 1 degree total). . That is what John was doing,he told me .The alloy needs to be harder than Lyman #2. John was using 80/20 Lino/WW.he said the bullets can be too hard. If you have a 1 in 14 twist the load will be 22 to 23 gr of Rx7 , if it is a 1 in 12 twist 20 gr of Rx7 works . I am copying what John did but in a 1 in 12 twist Hart barrel and shooting 1/4 to 3/4 in groups consistently using a Lyman 311284 bullet in 80/20 Lino/WW lubed with Tom Gray #24 Alum. gas check, bumped in a die cut with the same reamer that cut the throat and pushed with 20 gr Rx7.

   John taught me a lot hope this helps you.

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Lee Wiggins posted this 22 September 2018

Pic of a recent target. If you can see my note on top right target, the 36 Rx7 is NOT ( Repeat NOT ) grains of powder , It IS the setting on my Culver Conversion Lyman powder measure that throws a 20 gr. charge of Rx7.

                                                               Lee Wiggins

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Ken Campbell Iowa posted this 22 September 2018

... great stuff, guys .....  although my guilty pleasures  of being a slovenly plinker are rendered almost unbearable when i look at your teensy groups ....

ok, if johna will put together a cheater rig, so then will I ... there::   that is my challenge !! ...  after all, i suppose i could still plink with a 5/8  moa rifle ?? ...

**************

would like to see your chamber casting ....

thanks, ken

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Lee Wiggins posted this 22 September 2018

Ken,

   I will make a chamber cast this evening and post a pic.

                              Lee

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Lee Wiggins posted this 23 September 2018

Ken,

   Pic of chamber cast, 308X1.625 with bullet seated, Throating reamer with depth gauge (full 308 case). Reamer nose bushing centers front of reamer and 308 case centers back of reamer and is the depth stop.

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Ross Smith posted this 23 September 2018

All: I goofed. again. I measured the wrong ten cases. Today I measured the volumn of ten cases that I trimmed and fired in the rifle. The average water volumn did not change much. It is 39.8 grns of water.

What does this compare to Frank?

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Ross Smith posted this 23 September 2018

Lee: Fantastic, you nailed it, 14 twist Hart stainless. I took it shooting today and did bets with 20 gr r-7. But that was only one group. I was "testing" to see where the rifle shot best and the groups closed up at 20 gr and did well thru 24 gr. That's where I ran out of shells. Only have 33. I need to beg, borrow, steal, or buy some forming dies to make some more brass. I'll eventually get to shooting one case all day. I was shooting the 177grn eagan 330 with 2 grease grooves. I also have the 430 which casts 204 grn with 50/50 ww and lino. Still lots to learn about the rifle and the loads. I did out shoot a fellow with his brand new browning 6.5 creedmore.

My chamber cast showed .5 inch of freebore, but the casting wasn't as good as yours.

Miles to go

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Lee Wiggins posted this 23 September 2018

Ross,

   You mentioned 1/2 in. of freebore . I am quite sure that is the tapered throat from case mouth to where the taper crosses .308 groove diam. If you have a dial caliper or a micrometer you can easily check this. I would guess that you will get a diam. of .312 at the case mouth on your chamber cast. Please let me know what you measure at case mouth.

   You mentioned 50/50 ww/lino , I think a bit soft , try 80 Lino / 20 WW and you will most likely be able to push them faster with out accuracy falling apart.

   I shoot the same case all day. Deprime case, Prime case , throw a charge of powder from powder measure , push a bullet in case with my fingers , chamber , fire and repeat. Case is never resized and last till the primer pocket wears too much. 500 to 1000 firings.  It takes about as much time to reload the case as it does to read this paragraph.

Doing this you can change things without running home and loading again to try a different load, bullet , etc

 

                                                         Keep in touch, and good luck ,    Lee

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OU812 posted this 23 September 2018

Do a chamber cast and measure free bore diameter and taper. Surely someone on this site has a matching throating reamer to make the much needed bump die. I have squeezed down the fat Lyman 314299 bore rider to match barrel,but the heavy bullet caused too much recoil in my 10 pound rifle.7

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OU812 posted this 23 September 2018

I have the ten piece pilot bushing set for use with my ptg reamer. This helps measure throat/bore diameter when making die. Squeeze down fat bore ride section to fit bore with little resistance.

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Lee Wiggins posted this 23 September 2018

Ross,

   The freebore you mentioned I am sure is the tapered throat starting at the case neck tapering through the .308 groove. It is probably about .312 at the case mouth . Please measure your chamber cast at that point and let me know the diam. you measure. You also said bullets are 50/50 lino/ww. I think a little soft , try 80/20 lino/ww and you should be able to push them faster without accuracy falling apart.

To save time in experimenting load at the bench. I fire the same case . Reprime the case , throw a charge of powder from powder measure , seat bullet with fingers , chamber and fire , repeat. It takes about 15 seconds. Never resize the case. It will last till the primer pocket wears too loose , 500 to 1000 shots. Also a group will have been shot with perfectly matched cases ( the same case).

Keep in touch and good luck with your new toy, Lee

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Lee Wiggins posted this 23 September 2018

OOPS,

   Didn't think my post worked , should have seen Show more Post. I'll be more careful so I don't repeat myself

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Ross Smith posted this 23 September 2018

My bore cast could be better but its .311 at mouth and .311 in front of rifling. could be .310 but I have too many pits at that exact point. And I get .504"  long straight throat.   .346 neck and .457 shoulder 

Holding my 2 different slugs that came with the rifle, The longer slug looks like it would fit better, infact I'm surprised I'm getting +- 1moa shooting the short slug. I need to try the longer Eagan slug. The bore ride section goes from .311 infront of the grease groove to .301 at the ogive and it will touch into the rifling. The short bullet won't. That's opposite the notes that came with the rifle. I also have another tapered breach seat type bullet and several bore riders to try. 

I'm not a machinist, I'd have to get some one else to make a bump die. Can you bump 80-20 mix? 

Sounds like you've done this before Lee. 

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frnkeore posted this 23 September 2018

Ross,

Your case capacity is 2.58cc.

30 PPC = 2.20cc

30 BR = 2.44cc

30/30 = 2.88cc

.308 x 1.75 = 3.00cc / I found a listing for this, AKA .30 Doggie

308 Win = 3.47cc

Frank

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Lee Wiggins posted this 23 September 2018

Ross,

   Thanks for the info on your chamber cast. What you have is interesting because it is contrary to John Ardito's famous 1 degree throat. I'm scratching my head on this.

   By all means try the longer Eagan bullet and yes you can bump bullets that are even much harder than 80/20 or straight lino. But I question doing that assuming you want to tapered bullets for a cylinder throat. It is a bitch trying to get a perfect fit of a cylinder bullet in a cylinder hole (throat). Taper in taper is easy. I would just lube the long bullets and if you can chamber them , shoot them.

   Yes i've done this a few times . Threaded barrels chambered and throated with a throating reamer that i made. Have also cut a few bullet molds. I am lucky that I have a machine shop in my house. The wife isn't too happy with that when she steps on a sharp sliver in her bare feet that I tracked in.

                                                                                       Lee

 

                                    

 

e

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frnkeore posted this 25 September 2018

Ross,

For case forming, since you have a 30 deg shoulder, you could use a set of 300 Savage dies.

Push the neck back, most of the way, then trim. Then push it back, until it will just chamber, expand with a M die and fire form.

Frank

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Ross Smith posted this 25 September 2018

Frank: What would I have to do, cut the die off short?

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frnkeore posted this 25 September 2018

Yes, your shoulder is 1.145, the Savage, 1.558. Difference = .413. I'd go .420 to allow for a little spring back.

You may also need to polish the base of the die a little but, be sure to radius and polish the die so, that it doesn't gouge the case.

Frank

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OU812 posted this 25 September 2018

Lee, Thanks for posting the very interesting comments and pictures.

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Ross Smith posted this 25 September 2018

Frank,  The base to the wide part of the shoulder is 1.169, and to the top narrow part is 1.29 . About. The whole case is 1.62. Mine were trimmed short to 1.602 by the previous owner.

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Ross Smith posted this 25 September 2018

OU812: When you cut the inside shoulder in the case neck, I assume that you used an inside neck reamer? What was your setup for that? I need to do that to some of my cases, they have no shoulder. I do have 10 cases with shoulders but they are for a longer chamber and won't load in my rifle.The longer cases are 1.18 to the wide part of the shoulder and are trimmed to 1.618 but have a very (too) short neck. Anybody know what they are?

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frnkeore posted this 25 September 2018

Best I can:

6mm br= 1.075 to the shoulder

mine 1.145"

--------------------------------------------------------------------

Ross, I was going by the above. With the new measurement, you would shorten it .389, plus a few thousands for spring back, say .395.

Frank

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OU812 posted this 25 September 2018

My PTG neck reamer was guided using a snug slip fit pilot bushing fitted to bore. Then hand cut using their crude t handle. Reamer also has adjustable stop to cut free bore length. I know this is not the best way to guide reamer, but it did work.

Tom Gray mentioned he machines a hole at primer pocket to guide reamer along with snug slip fit pilot bushing.

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OU812 posted this 25 September 2018

OU812: When you cut the inside shoulder in the case neck, I assume that you used an inside neck reamer? What was your setup for that? I need to do that to some of my cases, they have no shoulder. I do have 10 cases with shoulders but they are for a longer chamber and won't load in my rifle.The longer cases are 1.18 to the wide part of the shoulder and are trimmed to 1.618 but have a very (too) short neck. Anybody know what they are?

I misunderstood the question. My rifle is chambered in 308 Winchester and using factory Lapua 308 Winchester cases. No special neck turning or cutting inside neck for me.

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Ken Campbell Iowa posted this 26 September 2018

speaking of throat configurations, i offer the following for interest:  using three match barrels ( 22 rimfire ) and 4 or 5 different chamber reamers with different throaters ... we found no accuracy difference between zero freebore and a freebore of nearly the length of the groove diameter of the bullet. ....

where cut,    freebore was snug fit on  bullet    taper was 1 and also 1/2 degree.

all three barrels and all combinations shot about 1/2 moa .

we felt there was a slight advantage to a chamber pretty tight at the front of the case.

***************

these were custom chambers, note that factory rifles error toward using any gritty loads you need to shoot at grizzlies and charging rabbits ...    but the above points to LBT type chambers might need a more serious try in a competition rig. ( long but tight freebore before rifling.  )   weatherby are long but not tight.

ain't this fun ??

ken

 

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RicinYakima posted this 26 September 2018

Is there anything the beats the Winchester 52 D chamber spec's?

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Ken Campbell Iowa posted this 26 September 2018

ric ... that was some 18 years ago, but then the 52d chamber was as good as the best ... heh. ...

 

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RicinYakima posted this 26 September 2018

"A good idea doesn't care who has it or when."

This thread on short cased .30 caliber cartridges is an example. We are just twicking the 1960 Barnes .308 X 1.5", or the PPC ones.

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OU812 posted this 30 September 2018

I think your gun is chambered in the Donald V. Eagan line of .30MX cartridges called the .30x1.6mx.

I will try to find link to where I found one of his old 1990's catalog.

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OU812 posted this 30 September 2018

Here is link to Donald V. Eagan catalog: You may need to download PDF

https://castbulletassoc.org/download/Eagan%20Catalog.pdf

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Ross Smith posted this 30 September 2018

OU: Thanks, after talking with Lee Wiggins, we think the exact one is the MX4 .30 ARD #2. That is the .311 version on the MX4 .30 ARD. It has a very slight 1degree taper just before the ogive. This rifle is getting more technical and challenging and interesting all the time. Just goes to show you can't just go buy a .5moa gun and go shoot .5moa just like that. There is a trove of info on this site if you know where to look.

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