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neck sizing in an ar15

nori11

Private
Minuteman
Feb 20, 2009
14
0
45
norristown,pa
im looking at buying a match grade ar barrel and most come with a matched bolt. im being told by some vetern shooters i can neck size with that setup.is there any more opinions on this logic.
 
Re: neck sizing in an ar15

I FL size my gas gun ammo.
With boltguns one can feel by force needed to close the bolt when neck sized only brass needs to be bumped back, something you can't do on an AR.

I'd neck size only for mine if I wanted to practice malfunction drills during matches........
 
Re: neck sizing in an ar15

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body"> I'd neck size only for mine if I wanted to practice malfunction drills during matches........
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And avoid crimping too?
 
Re: neck sizing in an ar15

I have necked sized only many times But eventually you run out of room,Or worse create more of a chance for slamfire.
Ive had this explained to me by a Veteran LR shooter.
He took the time to explain this simple fact to me when I had already made up my mind that there was no issues with Neck sizing only.He did me a favor even though I was stubornand unwilling to listen at 1st.

In reality and gas gun needs room to cycle properly.
If you keep ignoring the fact the shoulder displaces little by little after firing you create a bigger risk of slamfire.

Hey,,I got away with no issues for quite some time but why take the chance?
I didn't notice much if any improvements in my ar15 anyways.
I now use a redding body die and Lee collet die together.Actually I find my modified FL die works excellent as well(I drilled out the neck portion creating a body die
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).

In all reality I think using a FL die with carefull adjustments works fine in my own personal experience(only bumping the shoulder to a minimum say .002-.004).

For specialty use I think matching everything properly to your chamber and throat would be best for accuracy.Wouldn't that also require single feeding each round anyways?

So for normal magfed ammo it makes most sense to keep dimensions/sizing on the safe side IMO.

Like ive said,,,I have neck sized only along with mag feeding and neverhad any issues with cycling and reliability but that was just me.
Now I check to make sure my fireformed brass is at least bumped .002 back.
Its a semiauto NOT a bolt gun.
The AR doesn't have the leverage to close the bolt 100% properly if there is much interferance.
AR15's can and do blow up,I'm going to try and make sure I don't give mine a reason to
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.

 
Re: neck sizing in an ar15

Strip the bolt, put it back in the carrier and adjust your FULL LENGTH DIE until the
bolt will just close on your brass with no resistance. I do about 10 cases to get an
average reading. Then I put a piece of scotch tape on the head of a few cases and
make sure it takes some force to get the bolt to close. That is as tight as you are
going to reliably run an AR IMHO.
 
Re: neck sizing in an ar15

I necksize for my AR and have no issues at all and my loads are hot.
 
Re: neck sizing in an ar15

I neck-only size for my AR15 all the time. However, to address teh issues BuckyBrew brings up, I run the cases through the Case Micrometer to check the sholder position before neck-only sizing.

I especially agree that a gas gun needs clearance for the action to cycle properly, and than long or thick cases are asking for bad things to happen. So, if you are not going to measure the case don't neck-only size for gas guns.
 
Re: neck sizing in an ar15

Seems like a contradiction to me since supreme accuracy isn't the primary purpose for the AR15 platform. I would give neck sizing a try in comparison to full-length resizing to see if you experience any profound difference in accuracy. Logically neck-sizing should be more accurate since you are always using the same brass in the same chamber.

 
Re: neck sizing in an ar15

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 1911.it</div><div class="ubbcode-body">Seems like a contradiction to me since supreme accuracy isn't the primary purpose for the AR15 platform. I would give neck sizing a try in comparison to full-length resizing to see if you experience any profound difference in accuracy. Logically neck-sizing should be more accurate since you are always using the same brass in the same chamber.

</div></div>
The other point He made(Can't remember his exact name J keplar I believe
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) is neck sizing only will NOT give you consistent results if only because your brass is slowly stretching and thinning and considering the brass life along with having to fireform from a FL sized brass to begin with your better off trying to stick with a standard FL dimension instead of chasing your sizing.

In other words the gasgun was designed to cycle reliably with brass sized within spec.
What will you gain by 1st fireforming the brass(results on target will differ from neck sized only)?
You will be constantly chasing brass dimensions when you could just do your loadup within standard sizing dimensions from a FL die.
That would give you a better/consistent load IMO.
Consistency is what is most important anyways.

I havn't found much gain if any by neck sizing only in an ar15.
Maybe for specific LR single feeding(like mentioned),but I have not seen any gain and a FL diehas got me to MOA at 600yrds mag feeding and I have a piece of mind knowing i'm NOT pushing the safety factor.

Again,I know Neck sizing only does work and I would probably still do it if I was hand feeding each round for a specific LR accuracy attempts,BUT for anybody who doesn't have the tools to measure the shoulder displacement (Mitchalsup said) your taking chances and for the little if any gain its not worth it.
 
Re: neck sizing in an ar15

You need clearance for a gas gun to run without problems, especially if you are shooting CMP style matches. I have found that by bumping the shoulder back just .003-.004 in a full length sizing die with a neck sizing bushing (Redding)you will have no problems. To check this process properly you need to get a 223 micrometer from RCBS. Fire a round then check it, set your die to bump it back and you're GTG. This has given me flawless functioning while shooting 3000+ rounds a year.
 
Re: neck sizing in an ar15

I have not FL sized any of my brass for my AR guns yet, but I haven't loaded any once fired brass either. So my question is on how to properly set the FL sizer die. I will be using FL die with the redding competion set. My guess is the best way to do this would be to lift the case all the way up to the end of the stroke, then tighten the die down on the case. Then turn in very small increments to bump the shoulder .002 to .004. Now my second question comes with the use of the head space gauges. I see LE wilson makes them for specific calibers, while hornady makes them by size that work with multiple calibers. I guess I don't understand what part of the case comes in contact with the gauge. It has to be between the neck and the shoulder, but does it not matter where it touches, otherwise why else would you be able to use different calibers? Anyway the .223 and .308 gauges are easy to find but I need one for the 6.8 spc. Anyone know where to find one or what size to use, or will I have to drill one out?
Thanks to anyone who has the patience to read this
 
Re: neck sizing in an ar15

The Wilson gaugesare a quickdrop in gauge and there awesome for quickly double checking your brass as you go.They check from the datum point on the shoulder to the head of the case(NOT THE NECK).
It gives you the min/max by feel with your fingers(Believe it or not its very accurate) .This case also checks your Cartridge Overall Length(COL) fortrimming the necks if needed(also by min/max and feel by touch.
The RCBS precision mic is better used for fired cases in your chamber and setting up your dies to bump the shoulder and bullet seating depth.

You measure the headspace of your fired casesand use the gauge to adjust your dies to desired shoulder bump(usually around .004 in an ar15)
This die also measures from the datum point on the shoulder to the head but allows you to measure the difference between before and after fired cases in your chamber and adjusting your dies for the proper headspace.

I use both Wilson headspace gauges and rcbs precision mic and wouldn't have it any other way.
The wilsons are a quick drop in and out gauge for double checking,and the rcbs is handy for recording bullet seating depths between different bullets in your rifle as well as checking before and after shoulder displacement for die adjustments.
If your carefull you can simply use the wilson gauge and get proper sized brass by checking your fired brass and adjusting your dies until the brass drops in the gauge and the head is within the min/max on the gauge(very easy to see and feel).
I prefer both forkeeping track and for the rcbs gauges ability to help seat bullets to whatever you want while keeping track of how far you are from the lands(Its a mic and you can keeptrack of measurements).

GET BOTH!
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Not sure about the Hornady