Neck sizing for an AR?

klf

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Jun 30, 2011
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Has anyone tried with any success neck sizing for an AR? I single load each round and fire them in the same rifle. Your feedback would be greatly appreciated.
 

bigwheeler

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Oct 18, 2008
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Re: Neck sizing for an AR?

As long as your upper has a charge button. You'll gain nothing for all your effort
though. A lot of bench shooters have gone to bumping the shoulder a thou for accuracy so don't let that myth suck you in. Brass gets beat up in an ar anyway so
not bumping a thou or 2 is not going to change what it costs to shoot by a hoot or
a hollar or a counterfeit dollar.
I tried it years ago in the AR10t. It worked fine, I gained nothing. The ar15 does
not have the bolt mass the 10 does though.
 

turbo54

Mr. 7mm
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Dec 10, 2010
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Re: Neck sizing for an AR?

Try it. It won't work in any of mine. DON'T let the bolt carrier slam down on the cartridge when attempting to chamber the round....or you'll be beating your charging handle with a mallet to get the cartridge back out.

It is highly unlikely you'll get away with neck sizing only.

To answer your question more directly : yes, we've tried it and it doesn't generally work.
 

MontanaMarine

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Dec 9, 2001
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Re: Neck sizing for an AR?

Way back when, I used to reload 223 with a Lee "pound 'em in with a mallet" reloading kit. This was for an AR15 and I never had a malfunction.

Nowadays I full-length resize the 223 stuff because I have a couple of AR15s and I don't want to go to the trouble of segregating ammo and brass.
 

gvanhyning

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Re: Neck sizing for an AR?

I have reloaded for a 6.5 Grendel and I can tell you from personal experience that each and every case must be full length re-sized. I had to pay particular attention to insuring the full length sizing die completely bottomed out. The result in not doing so is a round that will chamber but not fully. The bolt assist will not help either and the result is a stuck round. The best way to clear this is not with a mallet, as suggested above, but just slam the butt on the ground or anything solid. This allows the weight of the bolt carrier group to do all the work. Good luck.
 

Graham

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Oct 30, 2007
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Re: Neck sizing for an AR?

Don't do it. You need to FL size for a gas gun. Your AR will bump the shoulder whenever you chamber a round anyway.
 

klf

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Jun 30, 2011
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Re: Neck sizing for an AR?

Thanks ALL. I think I will stick to full length resizing and skip the aggravation.
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