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Posted: 12/10/2009 12:29:14 PM EDT
| I just purchased a Bushmaster Target AR-15 with a 20" barrel. I want to develop an accurate round for it. I am using once fired LC brass, CCI 450 primers and Hodgedon 335 powder. The rifle has a 1 to 9 twist. Which bullet would be one of the best to use for accurate shooting. What is the heaviest bullet I can use? |
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Quoted:
What is the heaviest bullet I can use? Depends. The Privi 75gr HPBT on Widener's and Burger 73gr LTB HPBT, along with the Nosler 77gr HPBT can all be stabilized with a 1/9" twist. Thing is you need to actually measure your twist to see if it really 1/9" or slower because button rifling can be +/- a couple tenths of an inch. Faster, no issues. Slower.....issues. As ireload said, the Sierra 69gr MK is the heaviest bullet that is commonly available. It is a fine bullet. |
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Start with the 69 grain MK. Your rifle might shoot 75 grain bullets and it might not; 9 twist is right on the cusp of adequate rate of turn for typical bullets of this weight, and the bullet length of one bullet may cause it to shoot poorly while another of the same weight but a little shorter shoots okay.
The Privi bullets are cheap, not accurate, no matter their name. Every bullet in .224 diameter suitable for use in .223 Rem is easy to find, but you might have to look in two or three places to find them. The Berger is easily available through Sinclair and other suppliers. |
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I get the best groups ( at 200 and 300 yards ) in my Bushmaster AR15, 20 inch, 1/7 twist match barrel with this load( I tried many many powders bullets and primers ) LC case 77 gr Sierra MK CCI # 41 primer ( is a magnum primer ) 23.6 gr Varget ** 2.260 coal ** center of a sweet spot at 55 deg. to 110 deg. ( colder temp. add powder ) If you try the longer bullets ( single loaded ) Bushmaster barrels like 20 to 30 thou. off the lands |
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Even after you pick a bullet weight.......note that........brands will make a difference too.
Experiment..........find out what YOUR rifle likes. Aloha, Mark PS..........I trust that you've already looked at the Ammo Oracle, RIGHT? The majority of shooters, though, typically shoot bullets of 50 to 69 grains in weight (note that the 62gr SS-109/M855 bullet is as long as a 71 grain lead core bullet) and should select 1:9 twist barrels. At typical .223 velocities, a 1:9 twist will stabilize bullet lengths equivalent to lead-core bullets of 40 to 73 grains in weight.
If you havene't.......... http://www.razoreye.net/mirror/ammo-oracle/AR15_com_Ammo_Oracle_Mirror.htm |
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