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Posted: 5/21/2011 9:24:06 AM EDT
About to make my first ar purchase , saw an awesome deal on a PSA upper with a 1:7 twist. Probably wont be doing much shooting past 100 yrds ( at first) and will be shooting primarily 55gr cheapo ammo. Any great or truly noticable accuracy difference in shooting 55gr in a 1:7 bewtween 50-100 yrds compared to a 1:9? Thanks in advance
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Most likely you will not notice a difference. If you do notice a difference it will most likely not be because of that difference in twist rate.
There are so many things that impact accuracy that for the most part I think people overemphasize slight differences in twist rate. |
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1x7 will shoot anything a 1x9 will, plus the heavy stuff that the 1x9 won't. Some people argue that 55gr will shoot more accurate in a 1x9, but I have had no problems getting exellent groups out of my 1x7 with everything I put through it. I preffer the 1x7 I thought 1:7 was better at stabilizing the heavier stuff (better for accuracy), and that the lighter ammo couldn't handle it quite as well, sometimes fragmenting prematurely or tumbling (keyholing on targets). |
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1x7 will shoot anything a 1x9 will, plus the heavy stuff that the 1x9 won't. Some people argue that 55gr will shoot more accurate in a 1x9, but I have had no problems getting exellent groups out of my 1x7 with everything I put through it. I preffer the 1x7 I thought 1:7 was better at stabilizing the heavier stuff (better for accuracy), and that the lighter ammo couldn't handle it quite as well, sometimes fragmenting prematurely or tumbling (keyholing on targets). old wives tale. 55 shoots great in my 1/7's |
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1x7 will shoot anything a 1x9 will, plus the heavy stuff that the 1x9 won't. Some people argue that 55gr will shoot more accurate in a 1x9, but I have had no problems getting exellent groups out of my 1x7 with everything I put through it. I preffer the 1x7 I thought 1:7 was better at stabilizing the heavier stuff (better for accuracy), and that the lighter ammo couldn't handle it quite as well, sometimes fragmenting prematurely or tumbling (keyholing on targets). old wives tale. 55 shoots great in my 1/7's My understanding wasn't that it wouldn't work well, but that it was pushing the engineering limits. I'm sure in either case, there are better ammo and barrels that can make any such concerns not even worth mentioning. |
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One more quesiton  , how would ya'll rate PSA products, looking at purchasing all parts from them for my first build, without a rear site, the final price delivered for complete upper, LPK with MAGpul accesories, and stripped lower comes to 671.From what ive read here their uppers and lowers are excellent |
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1x7 will shoot anything a 1x9 will, plus the heavy stuff that the 1x9 won't. Some people argue that 55gr will shoot more accurate in a 1x9, but I have had no problems getting exellent groups out of my 1x7 with everything I put through it. I preffer the 1x7 I thought 1:7 was better at stabilizing the heavier stuff (better for accuracy), and that the lighter ammo couldn't handle it quite as well, sometimes fragmenting prematurely or tumbling (keyholing on targets). old wives tale. 55 shoots great in my 1/7's My understanding wasn't that it wouldn't work well, but that it was pushing the engineering limits. I'm sure in either case, there are better ammo and barrels that can make any such concerns not even worth mentioning. I have read about the 1/7 key holing, but that was with 40-45grn varmit ammo, not 55grn. At 100yrds I have never had key holing and I even shoot cheap under powered 55grn through a 1/7. |
| I have rifles in 1/7 , 1/9 and 1/12 and for the most part its all arbitrary my 6940 shoots 50 grain federal just as well as my howa 1500 and my bushmaster will group 75 grain hornadys just as well as my colt and what is really suprising is that all of my 223 rifles group well with sierra varmint master 60 grain bullet pushed with 2230 powder . 1/8 barrel would be an excellent compromise. |
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For absolute accuracy you want just enough twist to stabilize a bullet. But from what I can figure you wont be measuring groups with a micrometer so go with want you want. As for blowing up bullets, its tough to twist the jacket off a bullet at 5.56/.223 velocities. Get up to a fast twist .22-250/.220 Swift and use light bullets with twist rates built for 90gr VLDs and yes you can twist off the light jacketed varmint bullets. A sidenote, Ive shot more than a few rounds of 77gr stuff out of a Smith and Wesson AR. None of it hit the target sideways. |
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Quoted: This. I've shot as low as 45 grain once with no ill effects out of a 1/7. For absolute accuracy you want just enough twist to stabilize a bullet. But from what I can figure you wont be measuring groups with a micrometer so go with want you want. As for blowing up bullets, its tough to twist the jacket off a bullet at 5.56/.223 velocities. Get up to a fast twist .22-250/.220 Swift and use light bullets with twist rates built for 90gr VLDs and yes you can twist off the light jacketed varmint bullets. A sidenote, Ive shot more than a few rounds of 77gr stuff out of a Smith and Wesson AR. None of it hit the target sideways. It is my understanding that 1/7 will always be able to stabilize the heavy stuff, while 1/9 may or may not. Kind of determined on an individual basis. I've never shot a 1/9 twist AR15, so that's just what I've read on arfcom. |
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About to make my first ar purchase , saw an awesome deal on a PSA upper with a 1:7 twist. Probably wont be doing much shooting past 100 yrds ( at first) and will be shooting primarily 55gr cheapo ammo. Any great or truly noticable accuracy difference in shooting 55gr in a 1:7 bewtween 50-100 yrds compared to a 1:9? Thanks in advanceOne more thing....... your right you did see an awesome deal on a PSA upper and so did I. $399 
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, all i need to do is pick up a stripped lower locally.
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