Accuracy Consistancy issues

[Ripdog33]

Well I Built a 308 with an Aero set. Love the fit. I used a SS Rainier Match barrel and was shooting great. I have a Bushnell DMR 3.5-21x50 on an Alamo four star mount. The rifle runs great, spits cases at the 4-5 o'clock in nice piles. Has a Spring co buffer spring and a Heavy buffers CAR-10. My dumb @$$ may have done this on my own but I decided to use the TUBBS Final Finish kit. What started out shooting easy quarter size groups with no real focus, is not making me crazy. I am getting a few touching then a few 3-5inches low or off to the right. Thinking it may be my scope or mount, I removed them and tried my irons. Even irons are getting odd spreads but holding around a 3in group.

No it isn't me, with a SBR and 2moa aimpoint and crap duty trigger, I can do far better than this.

I am thinking of sending in the scope for an evaluation on the lifetime warranty and even testing out an AD mount I have.

Just trying to get conformation on my thoughts that I probably ruined the barrel.

[LRRPF52]

Why did you use an abrasive lapping system on a Ranier Match barrel? They are already hand-lapped multiple times by the barrel maker. I think they use Shilen barrels, which are well known benchrest barrels with a long reputation for accuracy. Hand lapped barrels have a soft plug with bore polishing compound on them run through over and over until the bore is smooth. They are then inspected for dimensional uniformity in the bore, before being shipped to the barrel smith.

All you need to do is shoot them, unless someone really screwed up the chamber reaming, and left really bad tool marks in the chamber, which can be cleaned with a polish by someone competent.

[GH41]

I hope I am wrong but it sounds like you tried to fix something that wasn't broke. The barrel had a 1MOA warranty. Now it has a no MOA warranty.

[Ripdog33]

The ultra match barrels are Shilen. Rainier does not specify which blank the match is nor did they confirm the match barrels were lapped. I figured it wouldn't hurt and guess I figured wrong.

[LRRPF52]

What did the bore look like through the borescope before you did the fire lap?

I would consider the fire lapping method on a pitted or older barrel, but not on a new one.

[Ripdog33]

LRR, did not look at it with a scope but was rough to clean. took a lot of patches. much easier after but of course, lost accuracy.

Said screw it and ordered another barrel.

[Blak1508]

Any chance of your rail or anything contacting your gasblock and tossing flyers?

[Ripdog33]

Any chance of your rail or anything contacting your gasblock and tossing flyers?

No, I have the M5E1 set up which has the rail bolted to the upper so it's more like a Mono upper and has a solid 1/4 in between the gas block and rail. I had the bipod also so I highly doubt it was touching the bottom. I'm pretty sure I screwed up a perfectly fine barrel.

[LRRPF52]

One thing with AR10's and .308 gas guns is that they require more manly application of the fundamentals to get the guns to shoot consistently. The amount of reciprocating mass and initial recoil are enough to wreak havoc on your position, so they really do better when solidly bagged.

A lot of people will try to free-recoil them, and groups will be all over the place. Your barrel may be ok, and you just need more technique to get it to shoot. Use a rear bag and a heavy bag that compresses against the sides of the handguard so the gun can't move much at all. Use a good trigger like a Geissele, AA, or Hyper-Fire. Dry fire until your reticle doesn't move outside of an inch at 100yds. I work hard to settle the gun before I break a shot, so it's like setting in a mortar base plate. I don't want the first or any follow-on shot to disrupt the position, so I troubleshoot it with small movements that settle the reticle into the center of the aiming point.

.308's are generally hard to tame in this regard.

[JC5188]

One thing with AR10's and .308 gas guns is that they require more manly application of the fundamentals to get the guns to shoot consistently. The amount of reciprocating mass and initial recoil are enough to wreak havoc on your position, so they really do better when solidly bagged.

A lot of people will try to free-recoil them, and groups will be all over the place. Your barrel may be ok, and you just need more technique to get it to shoot. Use a rear bag and a heavy bag that compresses against the sides of the handguard so the gun can't move much at all. Use a good trigger like a Geissele, AA, or Hyper-Fire. Dry fire until your reticle doesn't move outside of an inch at 100yds. I work hard to settle the gun before I break a shot, so it's like setting in a mortar base plate. I don't want the first or any follow-on shot to disrupt the position, so I troubleshoot it with small movements that settle the reticle into the center of the aiming point.

.308's are generally hard to tame in this regard.

Along this same vein...when I first bought my AR10 carbine, I immediately tried to "triple tap" a target. I didn't get the third round out of the pipe. The gun came almost completely off of my shoulder. I was used to the softer (and considerably smaller) 5.56 guns. The size of the gun itself requires me to fully extend the stock and get as forward a c-clamp grip as possible. It is almost comical, the difference in size.

My AR10 compared to my 6920...




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