13 MOA warped barrel-accuracy?

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Gunsallin

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My new target rifle had a 13 MOA warped barrel. I won't mention the manufacturer because I have had good luck with their rifles. I only had 5 clicks windage left om my Nightforce NXS after zero (took 52 clicks windage to center shot on target). Rifle is in the box being sent back to the manufacturer for warranty work. I shot about 100 rounds just to check the accuracy...not that great of results. 10 shots 1 MOA at 300 yards. Other rifles from same manufacturer were 10 shot .5 MOA at 300 yards. Has anyone experienced something similar and what affect did it have on your accuracy.....just curious....I have never experienced a barrel that warped before.
 
Years ago I bought a Savage varmint gun in 220 Swift. Would keyhole bullets at 100 yards. Savage sent a package pickup to me and I returned the rifle. A few weeks later I recieved the rifle back. With good handloads this rifle is a very good shooter. Has taken many a prarie dog at very distant ranges. Don't know how sometimes a firearm gets out of the factory doing something like this, but in my situation, Savage did the right thing.
Ralph
 
I recently bought a 6mm Shilen Match barrel, that had almost 0.090" deflection (warped*). If my math is right, that works out to 12 MoA. It was chambered in .243 Win, and slapped on a stock Ruger M77 action (formerly a .220 Swift). So far, accuracy does not seem to be suffering. The barrel has only seen twenty rounds, but it printed 2 sub-MoA 3-shot groups during that initial break-in; and the aggregate, of fifteen rounds fired, was under 1.5" at 100 yards (including clean-bore shots).


* Shilen believes that straightening the barrels creates extra stress, and does not do it. So, it wasn't a "defective" barrel, in the sense that it was warped; but may have been defective in the sense that it was too far out-of-spec. It's just something most people never think to check, or have never considered to be possible.
 
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is it just me?

Maybe my expectations are lower, ........but a rifle that will shoot a 10 rd, 1MOA group at .....300 yds.............. doesn't sound like that much of a slouch to me.

If the rifle is shooting 1 MOA at 300, surely its doing better than that at 100?

How 'bout some details on your "target rifle".

Is it possible that the 13MOA you needed to get on target was a scope mounting problem, receiver tapped out of alignment, something like that?

If your shooting a NIghtForce, you're in the big leagues , so tell me some more, how are you sure its the barrel?
 
Any time a barrel is warped it will only shoot its best groups at one known distance unless the warpage is perfectly vertical. If it's warped to either side you can only get the rifle to shoot to POI at one distance. Any manufacturer who sells warped barrels knowingly is selling unacceptable products. Think about it: it's like regulating a double rifle barrel set to a known distance. Beyond that distance or before that distance the rifle will not shoot to where the sights are aimed.
 
Any time a barrel is warped it will only shoot its best groups at one known distance unless the warpage is perfectly vertical. If it's warped to either side you can only get the rifle to shoot to POI at one distance. Any manufacturer who sells warped barrels knowingly is selling unacceptable products. Think about it: it's like regulating a double rifle barrel set to a known distance. Beyond that distance or before that distance the rifle will not shoot to where the sights are aimed.
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With the exception of the double rifle reference; all I can get out of your theory, is that you think the bullets will be travelling in an arc. So... are you saying that warped barrels will shoot "curve bullets"? ;) Nearly every barrel in the world is warped in some way.

....If you're referring to convergent and divergent paths: path of sight line versus path of projectile (your double rifle reference would be "path of projectile versus path of projectile, in reference to line of sight"), it's still no different than any other barrel. In a worst-case scenario, with my barrel (0.090" deflection from perfect, at the muzzle), I will be 0.090" from the intended point of impact at 200 yards (if sighted in for 100, with PoA and PoI at the same point). At 600 yards, it will be a whopping 0.450" theoretical deviation from the intended PoI. Given that a 10 mph crosswind can cause more than double that at 100 yards, and 21" of drift at 600 yards; I'd call that 0.450" pretty insignificant.

And, with my new barrel, I only had to run my scope about 5 clicks to the right. The previous barrel maintained the same lateral PoI as far as I could shoot (600+ yards). So, I find it safe to assume my deflection is up-and-to-the-right, or down-and-to-the-right. If my calculations are correct, that means the affective lateral deflection is only 0.009". At 600 yards, I would only be 0.045" from the intended lateral PoI. A 10 mph crosswind can cause more drift than that, before the bullet travels 5 yards!

And, as I said before: Almost ALL rifle barrels exhibit some kind of deflection.
You do know that most barrels are straightened by hand, and by eye, right? They generally don't get 'corrected' by some super-duper, fantastic machine. It's done by some one that eye-balls a barrel, tosses it on a mandrel, aligns it by hand, and guesses at how much pressure to apply with with the straightening press. When it looks "good enough", it continues on its way to the production line. Some barrels might be lucky enough to be air-gauged afterward, but don't ever expect that from anyone but a high-end barrel maker (and never on a standard production rifle from the big brands).

Next time you take your favorite, "perfect" rifle to a gunsmith for work, have them chuck the deflection. You'll probably be quite unpleasantly surprised at the results.
 
It's pretty normal to be hypercritical of a new (and presumably expensive) purchase. But it really sounds to me like you have a mounting issue rather than a barrel issue, and that maybe you've either got a rifle that is less accurate than others you've shot in the same brand, or perhaps you just haven't found the right load yet. Either way, the accuracy potential is there.
 
10 shots 1 MOA at 300 yards.
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1 MOA is 1 MOA at any range.

If you are shooting 3" groups at 300 yards, that's pretty good, unless you are doing benchrest competition.

Is it possible that the 13MOA you needed to get on target was a scope mounting problem, receiver tapped out of alignment, something like that?
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I suspect this ^.

If your shooting a NIghtForce, you're in the big leagues ,
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That's assuming much. There are plenty of folks out there with very nice equipment ...... that can't shoot up to it, and haven't a clue why. You can not buy skill.

Just yesterday there was a fella on here, a competitive 3 gun shooter, apparently, that blew up a spendy AR with handloads he put together on his spendy Dillon progressive press ....... yet had no idea what a good crimp looked like, or what it was for ........
 
I'm wondering where the "13 MOA" came from. Apparently, in the only testing done, 100 rounds, the rifle was getting 10 shot groups 1 MOA at 300 yds. Is the 13 MOA an addition of all the MOA's of the 10 groups fired?
 
What's "52 clicks" at 1/4 MOA per click come out to? 13?
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Yes, 52 divided by 4 (4 clicks to every 1 moa) = 13 MOA.

But it's hard to say that it's due to the barrel. Could be the base or rings causing some or all of the issue regarding the # of "clicks" to get sighted in...
 
I'm still not certain how it was determined that the barrel was "warped" (absent the barrel looking like a Krummlauf device). My first suspicion upon having to input a large amount of windage to zero a scope is that there is either a mounting problem with the rings/base, or that the scope base holes are drilled off center of the receiver.
 
Ok, this is how I came up with 13 MOA.

I use a 12" bull target at 200 yards to boresight. I use a locking benchrest. I remove the bolt, stand back about a foot from the butt, look through the barrel, and make adjustments with the benchrest until the bull is centered in the end of the barrel. I recheck three times before making scope adjustments. I move the scope to center of the target and recheck again three times. Just like sights, the end of the barrel is centered perfectly on the target. I then make my elevation corrections from bore to 200 yards and fire a shot. I have used this method many times on many rifles and have not had to make a correction more than 8” from boresight. I fired my first round and did not hit a two foot target. I had to place butcher paper in back of the target. I fired again and hit the butcher paper 26” to the right and 4” high. I made sight corrections and fired again, hitting 1” from center. I locked the gun in the vise with sights centered on target. The front sight (end of the barrel) was pointed 4” above the shot that hit 26” to the right. Now tell me, if you made corrections with an out of alignment scope, wouldn’t your final corrections be somewhat lined up with the target after corrections? I couldn’t believe this so I broke down the scope and rings, remounted with a different scope and rings, conducted the same process and valllla, 26” to the right and just a smidgen high again. All of my other rifles after boresight and corrections I can at least see the bull in the end of the barrel, not over 2’ out of center.
 
FYI,

FYI,

I boresighted a new TRG-42 with same procedures after the boresighting procedures identified above…..2” from center after first shot…….I think my boresighting methods should be good enough to hit a 2 foot target.
 
Based on the fact that you haven't actually measured the barrel, to make sure it's actually warped... My money is on a damaged crown, not a warped barrel.
 
My new target rifle had a 13 MOA warped barrel. I won't mention the manufacturer because I have had good luck with their rifles. I only had 5 clicks windage left om my Nightforce NXS after zero (took 52 clicks windage to center shot on target). Rifle is in the box being sent back to the manufacturer for warranty work. I shot about 100 rounds just to check the accuracy...not that great of results. 10 shots 1 MOA at 300 yards. Other rifles from same manufacturer were 10 shot .5 MOA at 300 yards. Has anyone experienced something similar and what affect did it have on your accuracy.....just curious....I have never experienced a barrel that warped before
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Gun drilling is not perfect. Having talked with a barrel maker, he spins blanks on center to determine those which have less wobble. Barrels with the least wobble are used on target rifles.

If your barrel is shooting bullets so far off that you are using too much elevation and windage to zero the rifle, then you have a legitimate issue.

A bud of mine had a Krieger barrel that used most of his windage in his scope to zero. Since he was a long range shooter he needed that windage back. His rifle was rebarreled and everything was good.

The removed barrel with so much offset, someone wanted a cheap long range barrel. The gunsmith turned the barrel 90 degrees so that the barrel was shooting low. The barrel shoots tight groups and was cheap, so this worked out well for the second shooter.

Receiver fronts that are not trued can cause elevation or windage issues.
 
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