Last year I purchased an new AR10 7.62x51. The only factory ammo that would average just under an inch was Federal Gold Metal MatchKing 175 grain. 11 other brands and bullet weights ranged from 1 - 5/16" (Federal GMMK 168 grain) to as much as 3 3/8" (PMC Bronze 147 grain).
20 - 5 shot groups of Federal GMMK 175 grain have averaged just under an inch at .953. The smallest group had been 11/16" (.68") and the largest has been 1 3/16" (1.18"). Due to my age (75), I no longer reload and factory ammo is what I use.
Around the 500 round mark I started getting flyers on groups. It was never the same shot that was the flyer. I thought it was me causing the flyers. Almost every group now had a flyer. I would fire another round and most of the time it would group with the other shots.
Now the groups are horrible almost every group. I tried different mags, 2 other scopes and mounts but that didn't help, 4 different Lot Numbers of Federal GMMK 175 grain ammo but they all shoot the same. I let someone else shoot it and it shot the same for him.
Out of desperation, I tried loading a single round into the chamber and shot it each time, this way, as a single shot. The groups shown is what it could shoot when it was new. I've checked what I could on the rifle and just don't get it why it shoots like crap when magazine feed compared to shooting single shot. When magazine feed, it appears that the bullets aren't being pushed back into the case as the overall length is still the same and it appears the bullet runout isn't effected but not having any measuring tools anymore (except for calipers), I really can't tell for sure.
I'm open for any ideas on how to correct this.
Colored targets are 1".
Flyers starting around the 500 round mark.
Magazine Feed as it shoots now
Single feed in chamber, single shot. This is typical accuracy when it was new, last year.
20 - 5 shot groups of Federal GMMK 175 grain have averaged just under an inch at .953. The smallest group had been 11/16" (.68") and the largest has been 1 3/16" (1.18"). Due to my age (75), I no longer reload and factory ammo is what I use.
Around the 500 round mark I started getting flyers on groups. It was never the same shot that was the flyer. I thought it was me causing the flyers. Almost every group now had a flyer. I would fire another round and most of the time it would group with the other shots.
Now the groups are horrible almost every group. I tried different mags, 2 other scopes and mounts but that didn't help, 4 different Lot Numbers of Federal GMMK 175 grain ammo but they all shoot the same. I let someone else shoot it and it shot the same for him.
Out of desperation, I tried loading a single round into the chamber and shot it each time, this way, as a single shot. The groups shown is what it could shoot when it was new. I've checked what I could on the rifle and just don't get it why it shoots like crap when magazine feed compared to shooting single shot. When magazine feed, it appears that the bullets aren't being pushed back into the case as the overall length is still the same and it appears the bullet runout isn't effected but not having any measuring tools anymore (except for calipers), I really can't tell for sure.
I'm open for any ideas on how to correct this.
Colored targets are 1".
Flyers starting around the 500 round mark.
Magazine Feed as it shoots now
Single feed in chamber, single shot. This is typical accuracy when it was new, last year.
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