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Discussion Starter · #1 ·
Anyone have any success with the sierra gameking 55 grain hollow point boat tail out of a 1/7 twist 20 in barrel. im building a bravo company ar 15 in 5.56 nato 223 I know all guns are different just wondering if anyone has tried or had any luck thanks:)
 

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IMHO with a barrel like the one your running a heavier bullet would be a better choice. I'd be looking for something in the 65-69gr range.
 

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kershal:

The only way to know if this particular combo works is to try it but I can tell you what didn't work for me:

I tried 52 gr hunting bullets in a 1 in 8 inch twist and the rotational forces of the spin caused them to disintegrate before even reaching the target. I then tried some 55 gr varmint bullets that made it to the target but accuracy was not good enough. When I went to the heavier bullets the result were excellent for accuracy. This, of course, was in a match barreled AR in 223.

So I think it better to match the bullets to the twist. If you MUST use the lighter bullets test them before making hundreds.

If anyone doubts my experience you can search here back a few years ago when I was asking for help on this issue. The consensus was slower better bullets or give the gun the correct heavier bullets.

LDBennett
 

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Exactly as LDBennett says about those lighter bullets in the faster twist rate barrels. While a 55 grain FMJ bullet is generally the work horse for the 5.56mm NATO military round, those light wieght prairie dog bullets can blow up from a fast twist rate barrel.

I'm not a computer whiz, but here is a site to check out and see for yourself:http://www.razoreye.net/ammo-oracle/AR15.com

This is a great site for this often asked question, and packed with information about the M193 vs M885 loads in the 5.56, as well as twist rates , bullet drop, etc.
 

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Discussion Starter · #5 ·
thanks LD Bennett and jim brady
ar 15 s are new to me ive always used a bolt gun 1/9 twist . you hear a lot of different ideas about what does and doesn't I saw some sierra 65 gr gamekings at midway in stock but not a lot of data in my load books for them but I do have data for the 69 gr gamekings but there not in at midway oh well I could always look at the 300 blackout with a different barrel looks like im going to have fun on the range well that's what reloading is all about right thanks again guys.
 

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Kershal - I just walked back in from testing a Bushmaster M4 with a 1:9 barrel to check accuracy and function with 55 grain M193 FMJs, and also to check the zero difference when using a CMMG .22 conversion kit and CCI Tactical .22 ammo.

As I was checking the zero for both at 25 yards, both the .22 LR and the 5.56mm 193s shot about 1 inch groups, with the .22 LR grouping about a half to 3/4 inch lower than the full power loads. I was just shooting from the prone position, and not off of a rest or bench.

I wasn't sure how well that faster twist would work with the lighter bullets, but they seemed just fine. It shot the 62 grain M885 rounds maybe slightly better, but not that much of a difference. These are FMJ bullets, and I'm thinking those are sturdier than the typical prairie dog bullets.
 
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