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Posted: 3/8/2010 5:05:24 PM EDT
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Is it common for a new match barrel to shoot not-so-good groups at first then start giving tighter groups?
Here's the background info: I put together a DMR-type AR using a White Oak Armament 18" stainless SPR barrel with 1-7" twist...I think the barrel has a Wylde chamber. The upper receiver is a Larue Stealth and the handguard is Larue Tactical LT15-12 Free Float handguard. Considering the parts used, the rifle should be a tackdriver...but after a couple of trips to the range, I'm a little disappointed with the accuracy I've been getting. I've been using some Winchester Q3131A...the Israeli-made M193 stuff from several years ago and it's been giving me 2" - 2.5" 5-shot groups at 100 yards. Not bad for mil-spec M193 55gr. FMJ ammo. With PRVI-Partizan 69gr. Match ammo, it's a different story. I'm having trouble keeping 5 shots in 4" at 100 yards. To say that I'm bummed out about this lack of performance would be an understatement...especially since I'm sitting on about 2K rounds of it. I know what kind of accuracy this ammo is capable of from reading the range reports of other shooters using it. I'm just kind of stumped why my rifle isn't grouping better with this high quality ammo. Total number of rounds through the rifle right now is around 140 - 160. I know there are a lot of experienced shooters that frequent this board, so that's why I posted here. I'm up in the air as to whether to switch to a different kind of ammo or sell the upper and start over with something different. Any advice or insights would be greatly appreciated... |
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Is it common for a new match barrel to shoot not-so-good groups at first then start giving tighter groups? Here's the background info: I put together a DMR-type AR using a White Oak Armament 18" stainless SPR barrel with 1-7" twist...I think the barrel has a Wylde chamber. The upper receiver is a Larue Stealth and the handguard is Larue Tactical LT15-12 Free Float handguard. Considering the parts used, the rifle should be a tackdriver...but after a couple of trips to the range, I'm a little disappointed with the accuracy I've been getting. I've been using some Winchester Q3131A...the Israeli-made M193 stuff from several years ago and it's been giving me 2" - 2.5" 5-shot groups at 100 yards. Not bad for mil-spec M193 55gr. FMJ ammo. With PRVI-Partizan 69gr. Match ammo, it's a different story. I'm having trouble keeping 5 shots in 4" at 100 yards. To say that I'm bummed out about this lack of performance would be an understatement...especially since I'm sitting on about 2K rounds of it. I know what kind of accuracy this ammo is capable of from reading the range reports of other shooters using it. I'm just kind of stumped why my rifle isn't grouping better with this high quality ammo. Total number of rounds through the rifle right now is around 140 - 160. I know there are a lot of experienced shooters that frequent this board, so that's why I posted here. I'm up in the air as to whether to switch to a different kind of ammo or sell the upper and start over with something different. Any advice or insights would be greatly appreciated... Loose barrel nut? Loose nut behind the trigger? 
Seriously, you haven't yet given us enough to diagnose if it's a problem or not yet... |
| I don't think some of you read that the OP is achieving 2-2.5" groups with M193 55gr. It sounds like your barrel may just not like that PRVI 69gr, which is odd, but not impossible. I'd try some different types of match ammo, perhaps some Black Hills, in the 69-79gr range, and see if you can't get the groups to tighten up. |
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What kind of firing have you done with it (numbers of groups shot, std dev so forth)?
Not all barrels will like X flavor of bullets used. Some people have had great success with some factory 69gn match loads and others not so much. If you can, try a variety of load types other than the std milspec stuff and see if your rifle likes any of them more. If it groups better, you know it's load sensitive and will need to find the right combination for your rifle, maybe even hand load some for max effect. If the groups remain terrible, then you've got some issues 
Did you purchase the ammo before the rifle because of its rep or did it work well with another rifle you own? Generally most shooters don't buy stuff in bulk until they know there barrel is inclined to it. On an off chance, you could also lend some to a friend and see what they group with it, how knows, you may have gotten a goofy batch? |
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What other info do you need? Atmospherics, magazines used, type of trigger, type of rest, scope/scope mount, your (honest) level of experience... Stuff like that! This was three different range trips. All were 65*F - 75*F with moderate humidity...RRA 2-stage Match trigger...Harris bipod w/bean-bag support under the buttstock...Burris XTR-14 scope in a Larue LT104 mount...I'm a moderately experienced shooter, I have a precision .308 that I regularly shoot and get 5-shot 3" groups at 500 yards with. I have enough experience to know this is a rifle or ammo issue, not a shooter issue. |
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I don't think some of you read that the OP is achieving 2-2.5" groups with M193 55gr. It sounds like your barrel may just not like that PRVI 69gr, which is odd, but not impossible. I'd try some different types of match ammo, perhaps some Black Hills, in the 69-79gr range, and see if you can't get the groups to tighten up. Actually I did. If a barrel nut is loose, it stands to reason that it will be "more loose" after shooting a bit. The fact that he shot Privi after the 55gr stuff just means that the info given is not conclusive... |
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What other info do you need? Atmospherics, magazines used, type of trigger, type of rest, scope/scope mount, your (honest) level of experience... Stuff like that! This was three different range trips. All were 65*F - 75*F with moderate humidity...RRA 2-stage Match trigger...Harris bipod w/bean-bag support under the buttstock...Burris XTR-14 scope in a Larue LT104 mount...I'm a moderately experienced shooter, I have a precision .308 that I regularly shoot and get 5-shot 3" groups at 500 yards with. I have enough experience to know this is a rifle or ammo issue, not a shooter issue. Fair enough. I had to ask to try and eliminate possibilities (or brings up things that would jog your memory). I have a similar setup as you (16" barrel, though), except my Privi shoots sub MOA out to 300 yards. After that it seems to open up a good bit. I have specific mags that I use when going for group size, and using a Larue mount definitely means its not a scope mount issue. |
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I don't think some of you read that the OP is achieving 2-2.5" groups with M193 55gr. It sounds like your barrel may just not like that PRVI 69gr, which is odd, but not impossible. I'd try some different types of match ammo, perhaps some Black Hills, in the 69-79gr range, and see if you can't get the groups to tighten up. Actually I did. If a barrel nut is loose, it stands to reason that it will be "more loose" after shooting a bit. The fact that he shot Privi after the 55gr stuff just means that the info given is not conclusive... Actually,I alternated the 55gr. & 69gr. back & forth....the 55gr.M193 is grouping tighter for sure. |
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I don't think some of you read that the OP is achieving 2-2.5" groups with M193 55gr. It sounds like your barrel may just not like that PRVI 69gr, which is odd, but not impossible. I'd try some different types of match ammo, perhaps some Black Hills, in the 69-79gr range, and see if you can't get the groups to tighten up. Actually I did. If a barrel nut is loose, it stands to reason that it will be "more loose" after shooting a bit. The fact that he shot Privi after the 55gr stuff just means that the info given is not conclusive... Actually,I alternated the 55gr. & 69gr. back & forth....the 55gr.M193 is grouping tighter for sure. This is what I assumed when I replied, which is why I believe it's an ammo issue, not a gun or shooter issue. |
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I don't think some of you read that the OP is achieving 2-2.5" groups with M193 55gr. It sounds like your barrel may just not like that PRVI 69gr, which is odd, but not impossible. I'd try some different types of match ammo, perhaps some Black Hills, in the 69-79gr range, and see if you can't get the groups to tighten up. Actually I did. If a barrel nut is loose, it stands to reason that it will be "more loose" after shooting a bit. The fact that he shot Privi after the 55gr stuff just means that the info given is not conclusive... Actually,I alternated the 55gr. & 69gr. back & forth....the 55gr.M193 is grouping tighter for sure. This is what I assumed when I replied, which is why I believe it's an ammo issue, not a gun or shooter issue. You know what they say about assuming...which is why I asked. |
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