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9/22/2017 12:11:25 AM
Posted: 7/10/2003 10:30:56 AM EDT
What are the required twist rates for barrels of different legnths to shoot accurately some of the new heavier loads like 69,75,77, and 100gn stuff?
Link Posted: 7/10/2003 10:33:02 AM EDT
69gr requires a 1:9 75gr & 77gr can shoot OK out of a 1:9 (depends on the barrel) but they work better in 1:8 or 1:7. 80gr? definately 1:8 or 1:7
Link Posted: 7/13/2003 11:39:27 AM EDT
After having read most of the AR15 accuracy books (by: zediker, martin, feamster etc.) I've found in my tiny little mind that not only is the twist important, but so is the chamber dimensions. That's why a Bushy varminter should shoot better than a regular bushy with some bullets. They have different chambers. The free bore before the bullet hits the lands and grooves counts for much. Another wild thing about bullets: It's not the weight after all, but the shape, the ogive. So some bullets of the same weight but with different ogives would shoot better with different twists. My brief and twisted understanding of a somewhat complex subject. M4-AK
Link Posted: 7/13/2003 7:40:58 PM EDT
Not only is the above important but so is barrel lenght since it directly related to velocity. All things being equal a slower rounds will need a faster twist to remain stable.
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