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#1
04-11-2003, 08:37 PM
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52gr. A-max problems
I have a 220 swift AI and have shot 55gr v-max with satisfactory results. I decided to try the 52 a-max. I went out the first day and loaded them with the same load I use with the 55's (45gr. RL15 @ 4250fps)
They shot bad, and I don't mean 1.5" groups compared to .5". I mean an 8" group. Now I was thinking something had to be wrong, like my scope is loose or something. I went home and inspected all parts of the rifle. Eveything checked out fine. Day two. Thought that maybe it was a fluke so I loaded some more this time just a tad hotter, they were around 4330fps. Shot my group, same result. [img]images/icons/mad.gif[/img] I was prepared this time and brought some of the ole trusties along, shot them into a nice little hole. So what do you think is happening with these bullets? [img]images/icons/confused.gif[/img]
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Timing is everything 
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#2
04-11-2003, 09:14 PM
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Re: 52gr. A-max problems
They are destabilizing because of the twist rate in your gun.
I had a similar situation with 55Gr Balistic Tips shooting fine but Sierra's Keyholing Like yours are doing or gonna do shortly. Sierra said switch to a different part# from thier line and they will shoot just fine in the 14 twist but that bullet, that was shorter than the BT in length (both plastic tipped bullets) but it stabilized differently and would not fly out of my gun. My brothers 223 shoots em just fine.
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If you have something that you disassemble and reassemble enough times, sooner or later, you'll have two!
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#3
04-11-2003, 09:22 PM
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Re: 52gr. A-max problems
Thanks,
My gun is a 16 twist, and I thought that it could be a stabilty problem but I did not think there could be that big of a difference between the two bullets.
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Timing is everything
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#4
04-12-2003, 12:19 AM
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Re: 52gr. A-max problems
Could be core to jacket separation. The 52 has a slight boat tail design and will not handle rpm as high as the 55.
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#5
04-13-2003, 07:24 AM
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Re: 52gr. A-max problems
MTBA, Just got my A-MAXs, I noticed they say on the box 1in14 twist, should work good in my VS 223. ALL, anyone tell me if H335 and Benchmark will work about the best for the 223 with these bullets? Put, lets say .005"-010" off the lands. Need some input from the pros out there, never shot the rifle yet, range opens up the 26th. Jay
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#6
04-13-2003, 04:19 PM
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Re: 52gr. A-max problems
I did notice the twist rate recomondation, but they were shorter than the 55's and with the high velocity of my gun I thought the rpm's might be high enough. Guess I was wrong. Oh well.
You should have good luck with H335 or W748 in your 223.
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Timing is everything
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#7
04-13-2003, 05:37 PM
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Re: 52gr. A-max problems
I shoot 52 AMAX out of my 223 with a 9 twist at almost 3300 fps with good results and out of my 22-250 at almost 3700 fps with a 12 twist also with good results.
.223: 3300 f/s with a 9 in/rev twist rate = 264,000 rpm They don't blow up at this RPM. 22-250: 3700 f/s with a 12 in/rev twist rate = 222,000 rpm Still ok ... 220 Swift: 4250 f/s with a 16 in/rev twist rate = 191,250 rpm 4330 f/s with a 16 in/rev twist rate = 194,850 rpm These are pretty high rpm, almost what I was getting out of my 22-250 ... I would think a 1 in 16 twist should be able to stablize a 52 Gr AMAX as long as they are going fast enough. Bullet RPM is a function of forward velocity. I'm sure stability is way more complicated than this, but one would think this would be ok ... Doug
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doug
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