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Posted: 6/28/2006 2:43:47 PM EDT
| I posted a range report a couple of days ago after shooting my new Rock River for the first time. I shot some old WalMart special Winchester 45 gr varmint ammo (at the time, I wasn't sure what grain they were) that I had in my safe. The accuracy was ALOT better than expected. I shot again yesterday at my "home range" (not the best, but a place to shoot) using some Winchester 64 gr power points, Federal 77 gr HP, and Winchester 45 grs again. I moved up to 50 yards to try out the new ammo. The cheap 45 gr Winchester ammo grouped ALOT better than the other ammo. My question here is this; what is SUPPOSED TO BE the optimal grain bullet for a 1-9 twist barrel? |
| I'm surely no expert, but I read an article in shooting times that suggested 75 gr to be the heaviest you should shoot in a 1-9 twist, and 45 being the lightest. Any heavier than that and supposedly you will have a problem stabilizing the bullet which affects accuracy. |
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My take on it is that every barrel and chamber is different. Bullet shapes vary from manufacturer to manufacturer and the optimum weight for your rifle may well be 62 grains, 55 grains, or the 45 that already has proven itself to you. The best thing you can do is test the different loads and gather data. Then and only then will you know what works best. For a 1/9, I'd stay at 62 or less. The 69 and up work better in the 1/8 & 1/7 bbls. Good luck. |
| When speaking in terms of purely optimal weight to twist, the 75/77 grain bullets are probably the best. The minimum amount of twist to stabalize is what you are looking for. However, the individual loading may suck in your rifle, so handloads to tune the load to your barrel might be necessary. Or try different lots of other manufacturers product, and different bullet weights. Also most rifles while having one favorite load will shoot other loads very acceptably. Good luck, and good shooting. |
69gr bullet is the optimal bullet weight for your 1:9 twist barrel. In this particular case, I attribute your accuracy to those winchester 45gr hollowpoint loads. That is the most accurate factory 223 ammo I have ever seen. It's what I would grab if I wanted to accuracy test a 223 rifle. I don't think you will find any other factory ammo that matches it in accuracy. I have seen that ammo shoot sub 3/8" groups @ 100m in a friend's heavy bolt gun. Not bad for FACTORY ammo...  The ammo CONSISTENTLY shoots very accurate in all guns I have tested it in. When I have customers wanting to accuracy test their guns, it's what I recommend to them as well. |
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Federal's gold medal match GM223M is loaded with a 69gr sierra matchking hollowpoint bullet. Midway has it. |
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