30 XCB, 2900 fps at 600 yards

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  • Last Post 19 March 2018
Larry Gibson posted this 11 March 2018

Got a chance to shoot 600 yards with my 30x60 XCB rifle using weight sorted 30 XCB bullet loaded to 2900 fps. I shot 46 rounds in 4 different groups.  The average group size was 1.3 moa. The results with pictures of the targets are at;

 

http://goodsteelforum.coms/topic/noe-30-xcb-30x60-xcb-600-yards/

LMG

 

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David Reiss posted this 19 March 2018

To 2nd what John stated above about being civil, I will add that this whole thread can be deleted with one keystroke, as I have done before. So this is a last warning, also offending members, and I do mean members will also be banned from the forum. For the sake of all members, kept it civil.

David Reiss - NRA Life Member & PSC Range Member Retired Police Firearms Instructor/Armorer
-Services: Wars Fought, Uprisings Quelled, Bars Emptied, Revolutions Started, Tigers Tamed, Assassinations Plotted, Women Seduced, Governments Run, Gun Appraisals, Lost Treasure Found.
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Larry Gibson posted this 18 March 2018

Frank

 

That is a beautiful rifle but I'd have to say that one sure looks like a match rifle to me....very nice.  What's the one you used in this thread look like?

Well here's the problem, we're talking 600 yards in this thread and you say you only have 300 yards there.  If you can't find someplace to shoot 600 yards up there then looks like you'll have to come on down here if we're going to shoot a side by side comparison at 600 yards. I don't mind shooting 300 yards as I do that here all the time too.  I Just haven't gotten up your way as I mostly swing through NE Oregon or the mid/upper Willamette Valley when I'm up that way.  Who knows though? 

LMG

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frnkeore posted this 18 March 2018

Thank you, 0U812.

It's not the one I shot in this post. It's a modern Hoch action, with a RKS barrel and a OH stock that I design and had a local stock maker crave.

Frank

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OU812 posted this 18 March 2018

Frank, That is one beautiful rifle.

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frnkeore posted this 17 March 2018

Excellent group Frank, but what were you shooting? Where's the 600 yard group, that is the range this thread is about? LMG
I guess you couldn't call my my rifle a match rifle either. It is a 1878 Sharps Borchardt, 20 years older that the 1898 Mauser design and made in 1878 or 9. The barrel, is a unmarked 33 caliber blank that I picked up at a gun show with a 15 twist, fitted and chambered to what I call 33 ELCO Max (33 cal 357 Max case) and then machined straight octagon. It sports a 20x Lyman Super Target Spot scope and the stock is one designed to shoot prone, back at the time these rifles where built.
I don't have a 600 yard range, available to me (300 is the longest I can access) but, I did invite you to shoot with me, about 7 years ago, when you live fairly close in WA, I'm still waiting for that to happen.
Yes, 2900 will give the XCB less wind drift than lesser velocitys, with that bullet but, a more aerodynamic bullet will give you less wind drift than the XCB at less velocity. That is my point. Now higher velocity with a higher, real BC would be a improvement  and hard to beat, if it where accurate.
Frank

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John Alexander posted this 17 March 2018

One of the valid reasons for having an internet forum is to allow different approaches, opinions, and evidence to be presented and debated. Relevant comments opinions and additional evidence presented by others can add further to the value of a thread .

Discussions and even arguments can be ways to learn more about cast bullet shooting and we still have plenty to learn. This is only true if the discussions are kept at a civilized level and without getting personal. I think this ongoing discussion has provided evidence that has been both interesting and worthwhile, at least to me. However, it has also gotten pretty close to the line of remaining civil at times. 

I urge all posters to make your points as strongly as you can muster with the best evidence but please make an extra effort to do it as gentlemen. 

John 

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OU812 posted this 17 March 2018

Cant becomes a bigger problem the slower the bullet travels. Frank better hold that rifle perfectly level every shot. I use to wonder what that spirit level on the end of my Browning BPCR was for.

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OU812 posted this 17 March 2018

In perfect conditions (prone or Bench) Franks combo should shoot 3" groups @600 yards. If his scope and mounts compensate for 354 inches of bullet drop I am sure he would do well. Just takes a little practice...think about it.

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Larry Gibson posted this 17 March 2018

Excellent group Frank, but what were you shooting? Where's the 600 yard group, that is the range this thread is about?

LMG

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Larry Gibson posted this 16 March 2018

Frank

This all is not your "point" but that's ok, we all understand.....

1. You don't need HV to shoot at 600 yards accurately and at long range, the wind is your most limiting factor.

I'm sorry Frank, I must have missed the part where you were elected, appointed, held a revolution or whatever that gave you the thought process that you could tell me what I "need" or don't "need".  Fact is; the wind is a limiting factor shooting any bullet at 600 yards.  You may be the exception though, can you enlighten us with your cast bullet 10 shot group results at 600 yards?

2. If you can not reduce wind drift with higher velocity, it serves no purpose.

You shouldn't  let your ire at me cloud your thinking; increasing the velocity of the XCB bullet over a lower velocity does reduce it's wind drift.

The only thing that you've accomplished is reducing trajectory, a good thing in hunting but, the bullet is a bit hard and would limit expansion, as well as shatter at close range, with that hardness.

The bullet has been tested at close range in wet pack.....it does not shatter.  The bullet has also been tested in wet pack at it's intended max range for hunting and it does expand because it retains sufficient velocity.  I base that on facts derived from actual testing Frank, not from gun rag or internet speculation. 

You brought up Schuetzen shooting and RPM in this thread, I was also responding to that.

No Frank, other posters brought up schuetzen bullets.

If you want to limit the scope of your thread, state that, in the beginning and stick to it.

May I ask where that rule is?  No, I ask you simply to try and stick to the topic.  You continually take any thread I respond on of on a tangent to prove some esoteric concept of yours.  As I stated earlier, go shoot your schuetzen bullet at 600 yards with 4 ten shot groups and come back with the results.  That would be "on topic".  Telling me I don't need to do what I did is simply argumentative.  I dare say a whole lot of members here shoot other than schuetzen rifles/bullets.....perhaps you think they don't need to shoot whatever else they want to?

Another thing that you state in this thread is that your rifle is not a target rifle. Can you tell us what features make it a none target rifle? Do you consider it a hunting rifle or varmint rifle?

No, the 30x60 XCB rifle is not a target rifle. It is a M98 action.  That's hardly considered a "target" action these days.  It has a sporter stock.  It has a Timney deluxe standard trigger with the pull set at 2.5 lbs.....a lot heavier than target or varmint rifle triggers or match triggers for that matter.  The 30x60 cartridge has none of the current design parameters of a target or benchrest cartridge. The barrel twist is not compatible with any long range match or VLD style bullets. 

I consider it a hunting rifle as part of the concept for the rifle was to extend cast bullet hunting capability past 200 yards to 300 or possibly 400 yards on game such as deer, antelope and coyote.  However, coyote are considered varmints but they are not the primary game for the rifle.  I have not, nor have I had, any intention of shooting any varmints such as squirrels or rock chuck with the cast bullet.  However the rifle is a 1/5 moa rifle with such bullets up through the 130 gr Speer HP at 3300 - 3400+ fps and could thus perform favorably in that regard.

So there you go Frank, you shoot your way and I'll shoot my way.  Last time I checked it's still a somewhat free country.  My invitation for you to come down and shoot a side by side 600 yard 10 shot group comparison with your Schuetzen against my 30x60 XCB is still open?

LMG

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frnkeore posted this 16 March 2018

LG,

I must correct myself on the CBA match, last year. I still won the 5 shot group match, by .001 but, it was .506 to .507 but, I was only 3rd in the 10 shot group match.

Frank

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frnkeore posted this 16 March 2018

My point, plainly stated is:

1. You don't need HV to shoot at 600 yards accurately and at long range, the wind is your most limiting factor.

2. If you can not reduce wind drift with higher velocity, it serves no purpose.

The only thing that you've accomplished is reducing trajectory, a good thing in hunting but, the bullet is a bit hard and would limit expansion, as well as shatter at close range, with that hardness.

You brought up Schuetzen shooting and RPM in this thread, I was also responding to that.

If you want to limit the scope of your thread, state that, in the beginning and stick to it.

Another thing that you state in this thread is that your rifle is not a target rifle. Can you tell us what features make it a none target rifle? Do you consider it a hunting rifle or varmint rifle?

Frank

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Larry Gibson posted this 16 March 2018

Frank

 

Read the title to this thread.  It's about the 30 XCB at 2900 fps at 600 yards.

Now read the post. It's about the 30 XCB at 2900 fps at 600 yards.

There's nothing there comparing it to any other bullet.  There's nothing there about CBA matches.  There's nothing in there about comparing results from 100 and 200 yards.  There's nothing there about comparing computer ballistics with other bullets. 

The rifle, the cartridge, the 30 XCB bullet were all designed and made for high velocity cast bullet shooting.  The report was just that; a report on the shooting of a very high velocity cast bullet at 600 yards.  If you're trying to make a point other than that could you please state it plainly?

If you want to make a valid comparison then take your rifle, your bullet at 2900 fps and go shoot 4 consecutive groups of at least 10 shots each at 600 yards and show us how it is done for real, not just theoretically.  You can even come down here and we can shoot a side by side comparison. Now wouldn't that be fun.....cool

LMG

 

 

 

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Larry Gibson posted this 16 March 2018

OU812

Your testing is looking pretty good so far. What cartridge?

LMG

 

Factory Remington 700 VS chambered in 223 Remington. Very easy on the shoulder and uses less lead and powder.

That's looking very, very good.....laughing

 

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frnkeore posted this 16 March 2018

Regarding my using a BC of .270, you'll note that I said, that I thought the bullet you use, actually had a BC of ~.250. The predicted BC in the cad program listed it as .287 so, I was giving you the benefit of the doubt, spliting the difference at the .270 figure.

I don't doubt that the 311299 came in below Lymans numbers, as the drawings of it aren't at that level. I used it because it's a well known bullet, using that .377 BC.

I have my own theory about why blunt nosed bullets don't have the designed BC's when shot at HV, based on aerodynamics.

Now I will give you real life bullets. Your .250 BC XCB and the Ideal 320366. I did the ballistic testing on the PB (reamed GC) 320366 with Barry Darr on his M43, a few years ago.

First note, that the drawing predicted a BC of .457 and the high BC of the tested bullet was ,454. Very close figures. On several other Spitzers, his M43 and the TMT cad software, where also very close and in 2 cases, the M43 showed higher BC's than the drawings.

Also, if you'll look at the CBA match results, you'll find that the difference at 100 yards, between PB and Hvy/UnR are very close. Last year, at one of the Roseburg matches, I won the 4, five shot match, over those two classes but, only by .001 with a average of .601 to .602. Although I won that the match, my slow twist (15), low velocity (1470 fps), low RPM was only on par with the 11 twist, 1900 fps rifles.

XCB Bullet:

.454 BC 320366:

320366 PB Drawing:

M43 results:

Then if we shot this same bullet at 1900 fps (GC version) we get this, at 1000 fps slower.

 Frank

 

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OU812 posted this 16 March 2018

OU812

Your testing is looking pretty good so far. What cartridge?

LMG

 

Factory Remington 700 VS chambered in 223 Remington. Very easy on the shoulder and uses less lead and powder.

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Ken Campbell Iowa posted this 15 March 2018

slowest possible stabilizing twist benefits mj bullets also ... the benchrest score 30 cal guys mostly choose 16-18 twist for their 110-130 grain bullets.  ( fattest bullet to touch scoring rings with light enough recoil for their varmint class ) .

it would seem that even those perfect mj bullets aren't really perfect at muzzle exit ....  i believe their best jackets are about 0.0001 to 0.0002 out of round ; jacket wall thickness .  even with this " minute " error slower spin is better ... btw, a good swiss lathe can better that runout with solid bullets .

and of course... even a perfect bullet before ignition may not be so perfect by the time it is blown out the muzzle, especially a near-liquid one such as our castings .

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

precession from the spin .... can spin change precession for better or worse accuracy ?? ...

just some thoughts... ken

 

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Larry Gibson posted this 15 March 2018

OU812

The Broughton barrel is a 3 groove but with standard military style rifling.  It is not 5R style.  The barrel cleans up extremely easily.  A wet patch (Hoppe's #9), 10 strokes with a wet brush (Hoppe's #9),  2 dry pates, a wet patch (WD-40) and a dry patch and its spotless.

BTW; the Broughton barrel has 2800 HV rounds through it so far. 

Your testing is looking pretty good so far. What cartridge?

LMG

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Larry Gibson posted this 15 March 2018

Frank

About 45 years ago I started shooting the 311299 and the 314299 (when it was introduced) because of the very BC you quote.  Thought, like many others, it would be just the ticket for LR (600 yard) shooting with the M1903s.  I shot if every way from Sunday with just about every load possible.  Found it would hold 2 to 3 moa 200 yards but more like 3 - 4 moa at 500 yards if started out at 2000 to 2100 fps.  The problem was that bullet did not hold up well transitioning sub-sonic.  I had my 1st Oehler chronograph in '73 so the velocities were known.  Lyman's chart, based on the .377 BC and 2100 fps, showed the 311299 bullet should have stayed sonic through 600 yards.  The problem was it wasn't.  It was dropping sub-sonic right around 500 yards.  Obviously the BC wasn't correct.   On the old 5V targets, if holding well, I could expect 60 - 70% hits in the black.  That was okay for practice but on the Decimal target scores sucked. 

Fast forward to 10 years ago when I got the Oehler M43 which actually measures the BC by measuring the TOF.  I found the published BCs, which were calculated, to be grossly over optimistic.  At 2000 fps the actual BCs of the 311299, 314299, the 311466 and the 311291 were actually .050 to .070 less than what Lyman says they are.  I have also found the BCs of newer designed cast bullets that are computed to be optimistic also.  An example being the 30 XCB.  It's actual measured BC is .250, not the .270 as quoted in the bullet specification drawing.  The 311299 out of a 10" twist is closer to .3000 and out of a 12" twist is closer to .315, both at 2000 fps.

 

Feel free to disregard RPM vs. accuracy but every single book on ballistics and even some reloading manuals tells us the facts; with a given bullet the higher the RPM the greater the dispersion (group size) will be.  Yes, you can sort through all the CBA match results you want and cherry pick results to verify your belief.  The problem there is all the other variables thrown in you're not considering. 

If you want to really see and understand pick one shooter with the same exact .308W cartridge/load at 2200 fps with a 311299, shooting under identical conditions with 2 otherwise identical rifles with the exception of one has a 10" twist and one has a 14" twist.  Oh heck, the rifles don't even have to be identical.  Have the shooter shoot 10 shot groups with each, alternating if you will and not knowing which rifle is which, at 100 and 200 yards with each rifle.  Measure the groups and you will quickly see the difference the increased RPM from the 10" twist made in group size.  On second thought, you won't even have to measure the groups....it will be very obvious visually. 

As to "shooter fatigue" that certainly is a consideration but after 46 rounds I wasn't fatigued.  Some may be though but even if we shot CBA military rules for score at 600 yards that would only be 20 shots plus sighters.  If that would fatigue someone is questionable.

LMG 

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frnkeore posted this 15 March 2018

1. Something that needs to be considered in shooting HV cast bullets, is the diminishing returns if you do it with a bullet that is of low ballistic coefficient.

2. It also, will contribute to increased fatigue and uncalled or called error (flinch), do to recoil.

Note the increased LR wind drift, as compared to a 311299 @ 2200 fps. Wind drift, being the major foe that we have in LR matches. Even the short range drift isn't of much difference @ +700 fps increase.

The 311299 @ 2200 fps .377 BC:

XCB bullet @ 2900 .270 BC, I believe the actual BC is closer to ~.250:

Regarding RPM Vs accuracy. The PB class should shoot much smaller groups and higher scores than the Heavy or Unr classes, If it were true that RPM decreases accuracy. In truth, they are fairly close @ 100 yd but, the higher velocity Hvy & Unr have a edge @ 200. In good conditions, 200 yards, isn't to different though.

The 200 yard disadvantage, being because of the EXTREMELY bad velocity range that the PB class shoot in. Wind drift becomes less, as you decrease velocity, below 1400 to 1500 fps and not only that, wind drift becomes less as you increase velocity above that range. We try to over come the disadvantage, as much as possible, by shooting high BC bullets.

1450 fps .480 BC:

2200 fps .377 BC

The .480 BC is a little over optimistic, there are a handful that shoot BC's that high but, most bullets are in the .400 - .440 range.

Frank

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