Hello everyone!
I find myself in a very strange situation (at least for me). My rifle went from 0.7" groups with Federal GMM to 3-5" groups with other match rounds which I bought when I ran out of GMM. At first I thought it was an issue with ammo QC, but now that it happened again with a different brand I'm not sure what to think anymore.
For the record, I live in Chile, South America, where .308 match ammo costs around 3 to 4 USD per round, and there is not much variety to choose from at any given time. We must buy whatever we can find, and because of local laws I can't sell this ammo to someone else if my rifle doesn't like it.
I'm going to describe this rifle's life so maybe someone can find a probable cause.
All group sizes mentioned here are 5 rounds, shot at 100yards, either prone or from a bench, rested on a bipod or a sandbag. I don't really shoot for groups too often, only now and then just to test new ammo and to check everything is funcioning properly. I shoot mostly at longer ranges (300 to 900 yards), at steel targets 2-3moa in size.
The rifle is a .308 Remington 700P with 5R rifling, 1/10 twist, made in 2018. It has a Sig Sauer Tango 4 Scope on top and a Harris Bipod. I am it's first and only owner.
The first rounds I fed this rifle were Winchester 168gr SMK. Groups started at 1" and got to 0.8" for the last few (I only bought 40 rounds of these).
I tried cheaper ammo with mediocre results as could be expected (3.5" with 150gr bulk ammo, and 1.5" with some hunting 180gr rounds).
Then I bought 200 rds of Federal GMM in 175gr. I got 0.7" groups consistently, and perfect long range performance.
At some point I added a large muzzle brake that I got from another shooter and I suspect it is a knockoff, but it performed really well without any accuracy issues that I could notice.
Running low and unable to find any more of the Federal GMM, I bought 300 rds of Remington Premier Match 175gr SMK, confident in the performance that SMK rounds had had in my rifle. They performed really well in the beginning, with consistent 0.6" to 0.7" groups.
Then I got a KRG Bravo stock, which I installed myself carefully following the instructions.
Some time later, after several boxes of the Remington ammo I started getting lots of fliers and some groups opened up to 5". I would sometimes get 2 or 3 rounds to land perfectly and a couple fliers, other times I would get all 5 rounds all over the place.
I cleaned the barrel, re torqued all screws, tested without the muzzle brake, gave it to other shooters to test, from the bipod and from sandbags, but thr groups still looked like shotgun patterns.
Then I found a partial box of GMM that I still had lying around, and shot a 0.7" group with them.
After this, of course I suspected the quality of the Remington ammo, and inspected the boxes and expended cases. I found out that I have 2 different lots, one from 2016 which I already expended, and one from 2019 from wich I still have 8 boxes. I found several cracked cases in the 2019 lot boxes (unfired rounds, with a crack in the neck where the bullet sits).
Convinced at this point that it was an ammo issue, I bought 300rds of Hornady Superformance ELD Match 168gr, which AFAIK have good reputation for PRS and NRL competition purposes. I tried them last saturday just before a match, and to my dismay I got the same result, 5" groups without any apparent reason (about half of the shots hit where intended and made a decent group, and the other half ended up 2 or 3 iches away). I ended up shooting the match with the Remington ammo, after inspecting and discarding all rounds with cracked cases. The results of course where not satisfactory, I missed lots of easy shots, and the corrections made upon observed impacts didn't get me any closer to hitting the target.
Later I talked with other shooters, who said they had (or heard of) the same issues with Hornady Superformance ammo (allegedly caused by their extreme speed, around 2800fps) and recommended getting rid of it, or at least rebuilding them in a press (I don't have a press, nor access to one).
Should I assume it's the ammo fault again? Maybe my rifle just doesn't like it? Maybe there is something else in the rifle that's acting funny?
Possible solutions I'm considering:
1) Test more kinds of ammo (really hard to do here as I expained earlier)
2) Try the Erik Cortina EC Tuner/Brake and see if I get good results with the Hornady ammo
3) Go back to the original stock
4) Try it without the brake
5) Change the scope for a Leupold Mk5
6) Reset everything to factory specs and build the rifle again starting from the scope.
I should probably do all of them, but I'm kind of hoping there is an easy fix that I just didn't see and will solve the problem without spending a fortune on additional accesories and boxes of ammo just for group testing.
Thanks in advance for any help you can provide.
Regards,
Stefan
I find myself in a very strange situation (at least for me). My rifle went from 0.7" groups with Federal GMM to 3-5" groups with other match rounds which I bought when I ran out of GMM. At first I thought it was an issue with ammo QC, but now that it happened again with a different brand I'm not sure what to think anymore.
For the record, I live in Chile, South America, where .308 match ammo costs around 3 to 4 USD per round, and there is not much variety to choose from at any given time. We must buy whatever we can find, and because of local laws I can't sell this ammo to someone else if my rifle doesn't like it.
I'm going to describe this rifle's life so maybe someone can find a probable cause.
All group sizes mentioned here are 5 rounds, shot at 100yards, either prone or from a bench, rested on a bipod or a sandbag. I don't really shoot for groups too often, only now and then just to test new ammo and to check everything is funcioning properly. I shoot mostly at longer ranges (300 to 900 yards), at steel targets 2-3moa in size.
The rifle is a .308 Remington 700P with 5R rifling, 1/10 twist, made in 2018. It has a Sig Sauer Tango 4 Scope on top and a Harris Bipod. I am it's first and only owner.
The first rounds I fed this rifle were Winchester 168gr SMK. Groups started at 1" and got to 0.8" for the last few (I only bought 40 rounds of these).
I tried cheaper ammo with mediocre results as could be expected (3.5" with 150gr bulk ammo, and 1.5" with some hunting 180gr rounds).
Then I bought 200 rds of Federal GMM in 175gr. I got 0.7" groups consistently, and perfect long range performance.
At some point I added a large muzzle brake that I got from another shooter and I suspect it is a knockoff, but it performed really well without any accuracy issues that I could notice.
Running low and unable to find any more of the Federal GMM, I bought 300 rds of Remington Premier Match 175gr SMK, confident in the performance that SMK rounds had had in my rifle. They performed really well in the beginning, with consistent 0.6" to 0.7" groups.
Then I got a KRG Bravo stock, which I installed myself carefully following the instructions.
Some time later, after several boxes of the Remington ammo I started getting lots of fliers and some groups opened up to 5". I would sometimes get 2 or 3 rounds to land perfectly and a couple fliers, other times I would get all 5 rounds all over the place.
I cleaned the barrel, re torqued all screws, tested without the muzzle brake, gave it to other shooters to test, from the bipod and from sandbags, but thr groups still looked like shotgun patterns.
Then I found a partial box of GMM that I still had lying around, and shot a 0.7" group with them.
After this, of course I suspected the quality of the Remington ammo, and inspected the boxes and expended cases. I found out that I have 2 different lots, one from 2016 which I already expended, and one from 2019 from wich I still have 8 boxes. I found several cracked cases in the 2019 lot boxes (unfired rounds, with a crack in the neck where the bullet sits).
Convinced at this point that it was an ammo issue, I bought 300rds of Hornady Superformance ELD Match 168gr, which AFAIK have good reputation for PRS and NRL competition purposes. I tried them last saturday just before a match, and to my dismay I got the same result, 5" groups without any apparent reason (about half of the shots hit where intended and made a decent group, and the other half ended up 2 or 3 iches away). I ended up shooting the match with the Remington ammo, after inspecting and discarding all rounds with cracked cases. The results of course where not satisfactory, I missed lots of easy shots, and the corrections made upon observed impacts didn't get me any closer to hitting the target.
Later I talked with other shooters, who said they had (or heard of) the same issues with Hornady Superformance ammo (allegedly caused by their extreme speed, around 2800fps) and recommended getting rid of it, or at least rebuilding them in a press (I don't have a press, nor access to one).
Should I assume it's the ammo fault again? Maybe my rifle just doesn't like it? Maybe there is something else in the rifle that's acting funny?
Possible solutions I'm considering:
1) Test more kinds of ammo (really hard to do here as I expained earlier)
2) Try the Erik Cortina EC Tuner/Brake and see if I get good results with the Hornady ammo
3) Go back to the original stock
4) Try it without the brake
5) Change the scope for a Leupold Mk5
6) Reset everything to factory specs and build the rifle again starting from the scope.
I should probably do all of them, but I'm kind of hoping there is an easy fix that I just didn't see and will solve the problem without spending a fortune on additional accesories and boxes of ammo just for group testing.
Thanks in advance for any help you can provide.
Regards,
Stefan
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