I'm no stranger to pulling extreme accuracy from an AR-15 but this is my first 10. I really appreciate everyone taking the time and effort to throw their ideas out but pretty much what has been addressed in everything above is what I'd consider common information and accuracy tricks we've all figured out along the way. I keep hoping someone will discuss the gas system/bcg/lock up as it relates to accuracy mostly because my gut feel is that I have a gremlin in that area and know very little about how to define and resolve issues there.
Its jmo, but its worked for me and Ive yet to see an AR outshoot mine.
Its a 20" Wilson Combat SS Heavy profile. I understand the bolt won't begin to roll until the gas system feeds it but why wouldn't the bolt begin to move as soon as the powder is ignited? Also it seems not going into full lock up could cause something like this. I know I'm dealing in tight tolerances here but I've had the same thing happening with 155 Palma's and 168 ELDM's. Groups almost identical to the one in the pic. I'm at the point where I have to start looking at the obscure and unlikely.i doubt it.
time says it does not move till the bullet is out of the bbl.
how long is the bbl ??
Its a 20" Wilson Combat SS Heavy profile. I understand the bolt won't begin to roll until the gas system feeds it but why wouldn't the bolt begin to move as soon as the powder is ignited? Also it seems not going into full lock up could cause something like this. I know I'm dealing in tight tolerances here but I've had the same thing happening with 155 Palma's and 168 ELDM's. Groups almost identical to the one in the pic. I'm at the point where I have to start looking at the obscure and unlikely.
Are these groups at 100yds? I don’t see these as flyers. Looks pretty good to me. This isn’t a benchrest gun after all.
Agreed, I know very well how to load for match work and I haven’t taken this gun to that level yet but I’m ready to move it that way now. That being said I’ve never had a gun that would consistently group four and throw one even in the early stages. They usually walk to tight groups from larger rounded groups. I tested it with the heavier buffer weight tonight and the group was slightly larger with the one it threw was out further. Tomorrow I’ll try A kinder gentler method of feed and see what happens.it cannot go anywhere till the gas moves the carrier, which moves the bolt.
stick to the basics.
how sorted is the brass
how uniform are the primer pockets
get a seating die that seats to a given depth.
you have too many things INCONSISTENT right now, confirmed by the same lack of accuracy with other bullets.
your loading process is not correct for target shooting.
Yes 100 yards. Thanks, but not good enough! I’m planning on shooting this gun in the Regional and State F-TR matches coming up. It’s gotta be tight!Are these groups at 100yds? I don’t see these as flyers. Looks pretty good to me. This isn’t a benchrest gun after all.
i doubt it.
time says it does not move till the bullet is out of the bbl.
how long is the bbl ??
Im sure it’s not the best upper/lower but it’s 7071 and a matched set. It’s pretty tight but could use a little shim work, maybe .002 or so here and there to get it 100% tight. I’ve built a couple really tight 15’s that shoot very well and based on that experience I’ll say this gun isn’t loose enough to be throwing flyers. Bipod is a mystic precision and I have the choice of a couple rabbit ear rears. Wilson Combat heavy stainless barrel, seated in the upper. Fail Zero BCG. Starline SRP match brass. The gun weighs in at just under 14# and is front weighted below the handguard and behind the bipod to bring it to 18#. It sits like a rock on the target and doesn’t jump much at all. The weighting isn’t the issue, it’s tightened the groups. Originally I had no intention of this gun being used in a serious match but then came the F-TR Regional / State idea... why on earth would I settle for my proven open class gun when I have the time to beat myself up making this thing shoot, lol. I started with a set of RCBS small base and taper crimp dies but I need to at least get the seating die to my standard of Forster micro seaters when I start walking it out to 600. I’m starting to believe that single feeding from a mag at full spring force may be the issue. Mag feed doesn’t effect my 15’s but this is a different beast.+1. Gas system negatively affects accuracy when something is broken, loose, or otherwise really not right. I think you answered this already; but what is your 10 upper setup? What's your bench or shooting setup for groups?
-Mac
I’m an internal volume guy.Brass- check case weight of the flier. Best if brass has received full benchrest prep first & cleamed.
On 243 brass, a difference of 3 grs makes a difference. I sort by 3/10 grs.
Lol, I have never yet bought a top of the line bullet. Just can’t make myself do it.Try a few rounds with 175 Bergers or Lapua Scenars instead of the SMKs
Im sure it’s not the best upper/lower but it’s 7071 and a matched set. It’s pretty tight but could use a little shim work, maybe .002 or so here and there to get it 100% tight. I’ve built a couple really tight 15’s that shoot very well and based on that experience I’ll say this gun isn’t loose enough to be throwing flyers. Bipod is a mystic precision and I have the choice of a couple rabbit ear rears. Wilson Combat heavy stainless barrel, seated in the upper. Fail Zero BCG. Starline SRP match brass. The gun weighs in at just under 14# and is front weighted below the handguard and behind the bipod to bring it to 18#. It sits like a rock on the target and doesn’t jump much at all. The weighting isn’t the issue, it’s tightened the groups. Originally I had no intention of this gun being used in a serious match but then came the F-TR Regional / State idea... why on earth would I settle for my proven open class gun when I have the time to beat myself up making this thing shoot, lol. I started with a set of RCBS small base and taper crimp dies but I need to at least get the seating die to my standard of Forster micro seaters when I start walking it out to 600. I’m starting to believe that single feeding from a mag at full spring force may be the issue. Mag feed doesn’t effect my 15’s but this is a different beast.
There is some pretty good info on this post...one thing I am not completely clear on...if shooting good tight groups with an AR-10 is the goal what is the point of having an AR-10 if to get these good groups you have to jack around with loading them one at a time???
Well, I'm curious now. It sounds as though you've certainly been doing this for a while; but some of the items listed are not what I'd expect for minimum group size. I've done a few 10s and acquired a 7SAUM upper that I love! (And my 308 too, thanks Carl at accuracy systems).
10s and 15s are super mag sensitive depending on the components. You list your 15s as not sensitive; try a Berger 70vld from the mag and I bet you find that your 15s become sensitive.
We're back to the diagnostics.
#1. Try a 10 shot group, single feeding as others have posted, or with a bob sled.
#2. Shoot '5' ish full load mag groups.
Compare results. Post Targets here
Count your shots on the full mags and post the fliers with shot numbers
Give a full breakdown and retorque all screws on your upper.
FYI try an accuwedge for upper/lower fit. Cheap and easy to use.
-Mac
ok, for some fun I’ll post a couple of my ar 223 pics. The small diamond is 4 shots at 500 yards and the large silhouette is at 1000 yards with no concern for wind correction, just watching my water line. 73 ELDM’s over Varget. Both were mag fed starting with 10 rounds loaded. It amazes me sometimes how if you ask a very specific question in these groups you instantly become the worst trigger man, builder, and loader around when actually results like these pictures is my everyday norm. I did get what is probably the one good answer, to not let the spring drive the round to chamber at full force. Many thanks for that and all the good discussion.Well, I'm curious now. It sounds as though you've certainly been doing this for a while; but some of the items listed are not what I'd expect for minimum group size. I've done a few 10s and acquired a 7SAUM upper that I love! (And my 308 too, thanks Carl at accuracy systems).
10s and 15s are super mag sensitive depending on the components. You list your 15s as not sensitive; try a Berger 70vld from the mag and I bet you find that your 15s become sensitive.
We're back to the diagnostics.
#1. Try a 10 shot group, single feeding as others have posted, or with a bob sled.
#2. Shoot '5' ish full load mag groups.
Compare results. Post Targets here
Count your shots on the full mags and post the fliers with shot numbers
Give a full breakdown and retorque all screws on your upper.
FYI try an accuwedge for upper/lower fit. Cheap and easy to use.
-Mac