Your custom barrel/build don't shoot. Next step?

[secondofangle]

I once read about an experienced BR shooter who said "If it don't shoot after 100 rounds, I quit wasting my time and get another barrel."

I have thought about that a lot over the years as I have tried numerous custom builds and on many occasions spent HUNDREDS of DOLLARS in ammo trying to find that goldilocks load that it likes.

Should I have just gotten another barrel?

Current situation is a 31" Kreiger 338 blank 1.25" straight contour that I had made for a DT SRS. I'll be damned if more than 10% of the 3-shot groups are better than 0.5-0.75 MOA at 100 yards. Trust me when I say I have ruled out shooter (installed a different barrel on the same chassis) and many other things. I have shot about 150-200 rounds through it.

So, is the most cost effective thing to a.) keep up with load development (I really really want it to shoot the 285 ELD-M); b.) have a differnt more experienced smith (this was the first DT barrel my smith did) rechamber and recrown it; or c.) order a Lilja or other barrel and start over.

Keep in mind that the blanks are about $350-400, the shop services are about $250-300 and the ammo is about $200 per 100 rounds. Thus I have already burnt up about $300 in ammo trying to make it work.

Thoughts?

 

[Ledzep]

Try at 300-400yd once on a calm day. More than once I've had a rifle that groups 3/4 MOA at 100, but is more like 1/4 MOA further out if the wind plays nice.

Try a different bullet. Yeah it sucks when what you wanted to work doesn't, but sometimes amazing changes in behavior occur when you load a different pill.

If both of those things fail, combined with everything else you've already done, I'd start looking at the rifle. Make sure the barrel is torqued on, look for machining defects in the throat and crown. Make sure the bedding is holding up.

If none of that works, look at a new pipe.

 

[Birddog6424]

Try at 300-400yd once on a calm day. More than once I've had a rifle that groups 3/4 MOA at 100, but is more like 1/4 MOA further out if the wind plays nice.

.

I've never heard of a rifle shooting loose up close and tightening up as it goes. I'm not sure I understand how a rifle can shoot .75 moa at 100 but a .25 moa at greater distance. I'm pretty sure that is in defiance of the laws of physics..

http://www.thetruthaboutguns.com/20...orn-do-groups-tighten-up-at-longer-distances/

 

[G17C]

I'll be damned if more than 10% of the 3-shot groups are better than 0.5-0.75 MOA at 100 yards.

What do the other 90% look like?

If it's roughly one shot out of 30 that is a flyer, my guess would be something with the ammo. I think any deficiencies with the rifle would manifest more frequently than that.

 

[SubOptimal]

It could just be that the barrel doesn't like that particular bullet. Try a different one.

 

[knockemdown]

Please describe your system for load development, re: powder(s) charge weight range, bullet jump/jam, etc.
You'll likely receive more focused responses if we know what you did and didn't try. As stated above, it may be as simple as switching bullet and/or powder...

Can you procure some quality loaded ammo to compare your reloads against?

Have you had a different shooter try your reloads? I can see how sparkin' off a .338 in a bullpup might not be the most enjoyable experience...

P.S. I'd also look to test loads @ 3-500 yds. Not because I subscribe to the bullet 'sleep' theory, but rather to stay realistic to the capability of that cartridge. IE, don't sweat what a .338 does @ 100yds, see how it's performing downrange...

 

[Erthal]

Hi

With Sierra 250 grains MK. the groups averaged 0.5 / 0.7 moa in my custom Stiller 338 LM rifle.. I spent 500 projectiles and was disheartened with the rifle. When I traded for Sierra 300 grains, I started to make groups of 0.2 to 0.3 MOA.
I gave up selling the rifle.

Try other bullets

 

[steve123]

Thought I had a bumm barreI, I hadn't run across a rifle that didn't like Berger hybrids until I got my 6mmFatRat upper. Out of a "what the heck moment" I decided to try 95's. Got some 95 SMK's in by mistake (wanted TMK's), with little load development they shot fantastic out of the upper! Went from 1.25" down to .75" at 100Y.

Had a 375CT that didn't shoot but MOA at 100Y, often slightly more, with Hooker 350 gr solids but the rifle would do well at distance. I spent a ton of money/$178 a bullet, at 100Y trying to get it to shoot decent, the day came I almost sent the rifle back but with the last of the days rounds I tried it at 400Y and turned in a 2.5" group, head scratching moment??? At times groups were less than MOA way out there but the best example was a 3 shot 5" group at 2100Y, Member DesertHK saw the pic right afterwards, he had already left. With another brand's 330 grain solid bullet it'd shoot less than moa at 100Y, fantastic at 1000Y - shot two separate 4-5" groups, but went to absolute crap by 1800Y. That rifle wouldn't shoot 350 SMK's worth a darn at any distance.

Had the barrel come loose on an AR - actually the extension, and on my old 6x47L bolt rifle the barrel loosened over time, long stories. If there's a screw it can come loose. loctite and/or torque wrenches are your friend.

Hope you get it ironed out soon!

 

[Ledzep]

I've never heard of a rifle shooting loose up close and tightening up as it goes. I'm not sure I understand how a rifle can shoot .75 moa at 100 but a .25 moa at greater distance. I'm pretty sure that is in defiance of the laws of physics..

http://www.thetruthaboutguns.com/20...orn-do-groups-tighten-up-at-longer-distances/

Now you have. I have had many loads that grouped the best at 100yd, but did not group the best at 300-400yd when the same loads were tested again. I don't load develop at 100 anymore. I load develop at 300-400 for group size, checking ES/SD, and only shoot at 100 to get my zero nailed down. The trend I have noticed, however... if it groups well at 300-400, it typically continues to do well out to at least the trans-sonic zone.

The physics of what's going on is absurdly complicated. That article waters the physics down pretty thin. The more assumptions you make, the simpler the physics/math gets... Doesn't mean it's right. You've got solid powder kernels turning into gas + solid (soot, carbon, whatever) at a variable rate crossing over sonic boundaries, generating variable pressures that are plastically and elastically deforming brass, bullet, steel (barrel), shock waves, harmonics, internal stresses, thermal stresses, rapidly inducing a 250,000-350,000rpm spin onto that little bullet before shitting it out into the atmosphere where you then get to play with viscosity, shear forces, magnus effect, etc. etc...

It's not really so simple as a parabolic arc with the addition of a drag coefficient and a perfectly linear dispersion cone.

 

[Birddog6424]

Now you have. I have had many loads that grouped the best at 100yd, but did not group the best at 300-400yd when the same loads were tested again. I don't load develop at 100 anymore. I load develop at 300-400 for group size, checking ES/SD, and only shoot at 100 to get my zero nailed down. The trend I have noticed, however... if it groups well at 300-400, it typically continues to do well out to at least the trans-sonic zone.

The physics of what's going on is absurdly complicated. That article waters the physics down pretty thin. The more assumptions you make, the simpler the physics/math gets... Doesn't mean it's right. You've got solid powder kernels turning into gas + solid (soot, carbon, whatever) at a variable rate crossing over sonic boundaries, generating variable pressures that are plastically and elastically deforming brass, bullet, steel (barrel), shock waves, harmonics, internal stresses, thermal stresses, rapidly inducing a 250,000-350,000rpm spin onto that little bullet before shitting it out into the atmosphere where you then get to play with viscosity, shear forces, magnus effect, etc. etc...

It's not really so simple as a parabolic arc with the addition of a drag coefficient and a perfectly linear dispersion cone.

Uumm, no. This isn't a "baffle them with bullshit" moment. The physics involved here are simple to understand.

All the factors you listed make for worse groups. Not better. Bullets don't curve back towards the target, which in a nutshell, is what you're saying.

 

[G17C]

IMO, good advice given above. In regards to precision vs. range and based on my limited capacity to understand;

While .75" groups at 100 yards might be disheartening, 7.5" groups at 1000 might not...

A load that consistently shoots .2 MOA at 100 is no guarantee it will do nearly as well at greater distances...

If I found myself in the same predicament as the OP (and since this is not a bench rest rifle), I would try different loads (and projectiles) at distances much greater than 100 yards.

Good luck with getting it sorted out to your satisfaction!

 

[Ledzep]

Uumm, no. This isn't a "baffle them with bullshit" moment. The physics involved here are simple to understand.

All the factors you listed make for worse groups. Not better. Bullets don't curve back towards the target, which in a nutshell, is what you're saying.

It's not as simple as "The bullet flies in a straight line unless otherwise affected by wind", and it's not a linear dispersion cone, ever. In basic theory, yes. In the real world, no. We're not talking about basic theory, we're talking about real-world events.

If that were the case, there would be no need for half of the inputs about the makeup of the bullet and twist rate that are in the more in-depth ballistic calculators. The wind blowing left/right wouldn't cause the bullet to rise/fall. There's torque and yaw effects going on that make it more complicated than a simple straight line.

What I'm saying is that to pinpoint exactly why and how a bullet performs irregularly like that, is extremely complicated. Maybe the chamber is cut off axis by 0.1 degrees and it damages the ogive/bearing surface junction and it takes a hundred yards for it to settle into a dynamically stable state after transitioning to the viscous atmosphere. Maybe one groove is bigger than the others. Fuck I don't know, and the amount of math/modeling you'd have to sit down and do to estimate the effect would be god damned complicated.

This is a great example. The display on the right is certainly not giving a smooth linear transition, especially within the first 100yd.
https://www.youtube.com/watch?v=KH9SCbCBHaY

The world is not perfect, nor simple. At any rate, you've got several people that have seen what I'm describing. Defies basic intuition, but physics is not the problem-- the physics are just more complicated than you initially think.

 

[lash]

LedZep, you will have to come up with some very real physics and scientific tests in order to convince me that a bullet will "correct" its path as distance increases under any circumstances. Just saying, "it's complicated" in a bunch of ways isn't doing it for me. If that were a real phenomenon, you can bet that the military would have done studies on it and published a white paper showing same. Find that paper and provide a link to it and I'll change my mind. Anything else is just mental masturbation.

Now, is it possible that in certain "real world" shooting scenarios, someone has shot a tighter group at distance than they were able to close up? Sure, I'll buy that. Any number of changing variables could allow this to occur in an occasional circumstance while out shooting for fun. Anything from how well and tight a person can hold at 100 versus longer range, mental challenges, and cross-wind or weather condition changes during a shooting session could give this appearance, among other things. But they did not occur because the trajectory "tightened up" after passing 100 yards.

 

[Supersubes]

It's not as simple as "The bullet flies in a straight line unless otherwise affected by wind", and it's not a linear dispersion cone, ever. In basic theory, yes. In the real world, no. We're not talking about basic theory, we're talking about real-world events.

If that were the case, there would be no need for half of the inputs about the makeup of the bullet and twist rate that are in the more in-depth ballistic calculators. The wind blowing left/right wouldn't cause the bullet to rise/fall. There's torque and yaw effects going on that make it more complicated than a simple straight line.

What I'm saying is that to pinpoint exactly why and how a bullet performs irregularly like that, is extremely complicated. Maybe the chamber is cut off axis by 0.1 degrees and it damages the ogive/bearing surface junction and it takes a hundred yards for it to settle into a dynamically stable state after transitioning to the viscous atmosphere. Maybe one groove is bigger than the others. Fuck I don't know, and the amount of math/modeling you'd have to sit down and do to estimate the effect would be god damned complicated.

This is a great example. The display on the right is certainly not giving a smooth linear transition, especially within the first 100yd.
https://www.youtube.com/watch?v=KH9SCbCBHaY

The world is not perfect, nor simple. At any rate, you've got several people that have seen what I'm describing. Defies basic intuition, but physics is not the problem-- the physics are just more complicated than you initially think.

I agree its complicated, and yes, ive heard that theory quite a few times. Always been hard for me to believe it though. A bullet, on a divergent path, doesnt just have to stabilize and begin flying straight, it actually has to steer back towards the center for that theory to hold up. So a bullet thats heading off to the left, needs to go right, a low bullet must go up, etc. I chalk it up to the shooter personally.



To the OP, have you contacted Krieger? The barrel is early in it's life, now's the time. At least get them thinking about it. I'm sure they'll recommend trying another bullet as the others have suggested, but youre in a better position than if you wait till the round count is up there. They may want to look at it now to make sure its dimensionally accurate, which would include the gunsmith machine work. I chambered a barrel recently that appears to be too big in the groove, based upon how the reamer cut(not a krieger). Would never have known had I not scoped it. Called the manufacturer, and they were very interested in it, and sent a call tag. It's there now being evaluated. Krieger and Bartlein are my personal favorites. Never owned or worked on one that wasnt a stunner, but im sure one day it will happen.

 

[Ledzep]

I don't claim to understand it, either. Don't get me wrong. But I've seen it several times in my own and others' rifles-- to the point that I changed how I do load development. There is work out there by Bryan Litz and others that suggests that there is a transition period that takes anywhere from 75-180 yards out of the muzzle for the yaw effects to smooth out.

When things move through a fluid (air, water, whatever), there are constant and variable forces on that object that come from viscosity and pressures. It's not as simple as a projectile in a vacuum flying in a straight line through space. Throw in some 300,000rpm spinning and some funky shit can happen.

https://www.youtube.com/watch?v=5zD7Le2mGFg

 

[Rhyno]

You know Litz tested this in his last book have one of them come in here and say something.

 

[Supersubes]

You know Litz tested this in his last book have one of them come in here and say something.

Pretty sure Litz has a standing offer to pay all expenses to the person who can prove this theory.