AR15 consistent grouping issue??

Also,from a reloading standpoint, various primers and seating depths have been tried along with detailed brass prep.
I can only conclude that it is either in the gas system(but I don't have a clue if the gas system would do this) or the barrel is "bad" or fitment/torque is not proper.
Never had anything like this...ever!
Going to get it shipped back and hopefully will find out what the issue(s) are. Thanks to all for the suggestions.

Gene
 
Originally Posted By: G AndersonOriginally Posted By: SnowmanMoOriginally Posted By: G AndersonOriginally Posted By: SnowmanMoI think that you have answered your own question. IF you have taken all the steps, including changing out optics and mount, and it still does it, then as Holmes said, if you have eliminated the impossible whatever remains however improbable must be the truth.

It seems to be a bad build, send it back. To do otherwise is just an exercise in futility and will simply frustrate you. Whether it's barrel torque, a bad barrel, that all sits with the builder and you shouldn't do anything about it.

As an armorer, I take great pride in the guns we send out the door. Every now and then we get one that acts up, and we encourage our clients to send them in to us so that we can get it fixed and to learn from it so that it doesn't happen again.

Good luck, please keep us posted on the progress.

At that point now...just wanted to try every conceivable thing to rule out something wrong with the build. I always start with myself first, reloading issues/techniques, bench issues/techniques before blaming a bad rifle/barrel. I've had a few finicky rifles before and eventually got them shooting great, but nothing like this.

Thanks and I will let you know what ends up happening.

Yeah, that's the way it sounded. But it looks like you dotted the I's and crossed the T's, except for the single load test.

I did the single load today...out of 5 groups, one did not follow the typical pattern...the other 4 did the same "2nd shot out" thing.
Just for future information, if the single load did change things...what would this conclude the problem to be and what would the ultimate solution be? Obviously, I wouldn't want a single shot AR...

Thanks

There could be a couple of possibilities if the problem had disappeared with the single shot test. One, it could be a loading issue where the cartridges are getting damaged going from the magazine up the loading ramps and into the chamber. I once saw a customers AR-15 that kept jamming and on further inspection we found that it tended to jam when loading cartridges from the left side of the magazine follower. A little ramp polishing and a minor spring adjustment in the magazine fixed that up. It could have also been an indication of a timing issue. AR's are sensitive to timing issues. The BCG's do not always go back with the same velocity due to timing. If the bolt is dragging while unlocking it could throw the whole BCG out of time and cause a feed issue that could be causing some inconsistencies like a magazine issue.

So now, sine you have done your due diligence and tested out the variables and the problem persists, it has to be something in the build. My suspects would be barrel, barrel torque, barrel interface or a problem with the upper receiver.

You eliminated the optic and mount, ammunition, and gas system/bcg with the single shot test, so that's all that's left. I once had a bull barrel .223 that suddenly lost it's ability to hold a group and found that the upper was fatigued. I discovered it while checking barrel nut torque. Seemed that when the barrel/upper interface heated up the upper would flex too much. Changed out uppers and it went right back to driving tacks.

Switching out lowers wouldn't change anything but I am glad that you did the test, just to rule out that one off anomaly.

Thanks for the updates, keep them coming.
 
Originally Posted By: SnowmanMoOriginally Posted By: G AndersonOriginally Posted By: SnowmanMoOriginally Posted By: G AndersonOriginally Posted By: SnowmanMoI think that you have answered your own question. IF you have taken all the steps, including changing out optics and mount, and it still does it, then as Holmes said, if you have eliminated the impossible whatever remains however improbable must be the truth.

It seems to be a bad build, send it back. To do otherwise is just an exercise in futility and will simply frustrate you. Whether it's barrel torque, a bad barrel, that all sits with the builder and you shouldn't do anything about it.

As an armorer, I take great pride in the guns we send out the door. Every now and then we get one that acts up, and we encourage our clients to send them in to us so that we can get it fixed and to learn from it so that it doesn't happen again.

Good luck, please keep us posted on the progress.

At that point now...just wanted to try every conceivable thing to rule out something wrong with the build. I always start with myself first, reloading issues/techniques, bench issues/techniques before blaming a bad rifle/barrel. I've had a few finicky rifles before and eventually got them shooting great, but nothing like this.

Thanks and I will let you know what ends up happening.

Yeah, that's the way it sounded. But it looks like you dotted the I's and crossed the T's, except for the single load test.

I did the single load today...out of 5 groups, one did not follow the typical pattern...the other 4 did the same "2nd shot out" thing.
Just for future information, if the single load did change things...what would this conclude the problem to be and what would the ultimate solution be? Obviously, I wouldn't want a single shot AR...

Thanks

There could be a couple of possibilities if the problem had disappeared with the single shot test. One, it could be a loading issue where the cartridges are getting damaged going from the magazine up the loading ramps and into the chamber. I once saw a customers AR-15 that kept jamming and on further inspection we found that it tended to jam when loading cartridges from the left side of the magazine follower. A little ramp polishing and a minor spring adjustment in the magazine fixed that up. It could have also been an indication of a timing issue. AR's are sensitive to timing issues. The BCG's do not always go back with the same velocity due to timing. If the bolt is dragging while unlocking it could throw the whole BCG out of time and cause a feed issue that could be causing some inconsistencies like a magazine issue.

So now, sine you have done your due diligence and tested out the variables and the problem persists, it has to be something in the build. My suspects would be barrel, barrel torque, barrel interface or a problem with the upper receiver.

You eliminated the optic and mount, ammunition, and gas system/bcg with the single shot test, so that's all that's left. I once had a bull barrel .223 that suddenly lost it's ability to hold a group and found that the upper was fatigued. I discovered it while checking barrel nut torque. Seemed that when the barrel/upper interface heated up the upper would flex too much. Changed out uppers and it went right back to driving tacks.

Switching out lowers wouldn't change anything but I am glad that you did the test, just to rule out that one off anomaly.

Thanks for the updates, keep them coming.

Thanks for the info...I had thought along those lines and did eject some non fired rounds to see if there was any damage to the bullets and they looked good. Interesting about the upper having fatigue issues...what would have caused this? Just a lot of rounds fired thru it or an over pressure situation?

Gene
 
I know it probably going to sound dumb, but have you shot any factory loaded ammo just to see if the problem is still there? I read all three pages of the process your going through but didn't see factory loaded ammo mentioned. We all get that un-explained out of the group shot and it will drive you crazy crazy. I shot a box of factory stuff just yesterday to rule out maybe my rifle was a POS. Turns out its my reloads.
 
Originally Posted By: pyscodogI know it probably going to sound dumb, but have you shot any factory loaded ammo just to see if the problem is still there? I read all three pages of the process your going through but didn't see factory loaded ammo mentioned. We all get that un-explained out of the group shot and it will drive you crazy crazy. I shot a box of factory stuff just yesterday to rule out maybe my rifle was a POS. Turns out its my reloads.

No factory stuff run thru it...is 6x45 ammo available in factory offering? Never really looked for any.
I am the first to admit that flyers occur every now and then and I "choke" more times than I care to remember on the last shot of a group, but we are talking almost 400 rounds now with various bullets, brass, primers, powders, seating depths, shoulder bump variations, etc...hard to imagine something not working thru all of the rounds fired.
I am leaning more toward barrel fitment/torque because of the predictable and repeatable group flyer from the 2nd shot repeatedly...this isn't a case of random "bad" groupings.
I just tried another complete scope and mount today(4th different scope and 3rd different mount)...same thing.
 
Sorry man, guess I had a brain fart and forgot the caliber. But I plan on keeping up on this post until you figure out the problem
 
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