neck size cases in ar

9

98 220 swift

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Is it possible to neck size the cases that was fired in the same ar. Rifle is only used for target so reliability is not a major concern. But I still don't want to have alot of failure to chamber problems a few every now and then would not be a issue. Figure it could help get some more accuracy. I used a lee collet die on a few cases that had been fired from the same rifle. The bolt closed fine on the empty cases. Does anyone else do this?
 
Anything is possible, but I always full-length size cases that are going to be fired in an autoloading or pump rifle. That's just me.
 
Cases fired in the same rifle I would expect no problems. I do not have an AR, but I neck size 6mm Remington and 30-06 for my bolt rifles and never have had a problem (50 years of reloading), so I do not see why you would. As I understand it a semi-automatic rifle has slightly bigger chamber dimensons than a bolt rifle to accomodate the auto loading action. Essentially I think more 'Slop' is to your advantage. load a few magazines worth and see how it goes. Just make sure the cases were previously fired in your AR. Report back your results. It would be good information for others interested in the same thing.
 
If you full size with .001 headspace will be better then neck sizing only even in your AR used for accuracy. I'm a bench rest shooter that use to neck size fire formed cases. The common problem with F/L sizing is over sizing fired cases. When resizing fired cases with a full size die & size to the minimum, you have the best of two worlds. Accuracy without hard chambering. If you must neck size fire all cases with the same headspace measurement. Cases after firing may get wider & not longer could cause.003 headspace. As to your question, you could neck size. Just check in a case gauge or RCBS Precision mic for headspace measurements.
 
While it is possible, it will not do anything to improve accuracy. Why?, because unless you have a match chamber in your AR (which are few and far between, Bushmaster made one for their Varminteer rifle with a 26 inch bull barrel) your cases will spring back to almost their original size even after being fire formed.

AR chambers are reamed to accept a large variety of different mfg's rounds in a semi-auto mode in most cases as 5.56 ammo which has slight different dimensions than what you will be using with 223 dies. You in effect be resizing the cases to 223 dimensions and not exact 5.56.

While neck sizing fire formed cases works very well for bolt action rifles with tight chambers, it is of questionable value for semi-auto's.

To help improve your accuracy, you efforts would be better spent on replacing an AR's trigger group with a Match (adjustable) trigger or spending your money on a percussion made bolt group and stainless steel firing pin.

Making better and more consistent reloads (amount and type of powder) will go far in improving accuracy. Neck sizing will be at best minimal in your search for a better round to fire out of your AR.

I full length resize in small base dies my cases for 223/5.56 to insure there will not be any feeding issues.

Good luck and strive for more consistent reloads in your pursuit.
Stay safe.
Jim
 
I can't believe I'm the only one so far that thinks it's a stupid idea . The cases in a semi or at least all my AR's don't come out with a consistent fire formed , "case head space" . Unlike my bolt guns that come out exactly the same or pretty darn close . When neck only sizing bolt guns at some point you still need to FL size the case back down . That number varies but lets just say every 4 firings you'll need to FL size because the case stretched to the point it's hard to chamber .

Now remember we're talking about a bolt gun being hard to close the bolt on after 3 firings . They have leverage to do so and it's still hard to do it after just neck sizing 3 times . The BCG of an AR does not have the ability to force the bolt closed like you are able to do with a bolt gun . Couple that with not all the cases are going to have a consistent case head space ( measurement from head to datum point ) so you don't know from cases to case how close you are to being over sized .

But OK lets say it works on all your once fired from your rifle cases the first time . You now have had them go through the firing process and be inconsistently expanded twice now . At this point it's very unlikely any of the cases have not grown to very close to max case head space and a few likely are now longer do to the cases being extracted while still under some pressure twice .

So now you've fired them once , neck sized and loaded them once and now are about to neck size and load them again . oh no but wait are you sure each case you are about to shoot for the third time is your case fired from your gun each of the previous 2 times . They were likely flung from your rifle and you had to go pick them up . Are you 100% sure a piece of brass from someone else gun did not make it into your rotation ???

Just does not seem worth the effort to me .
 
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Neck Tension

The lee collet die may not produce enough neck tension for an AR. Resulting in bullet movement on chambering. Neck sized brass are larger in the body. The fat brass slows feeding in some magazine, not all, when i neck sized for my M16A1. Alternate between fl & neck sized may work, but not a good idea with light neck tension. http://www.exteriorballistics.com/reloadbasics/gasgunreload.cfm From Sierra.
 
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[QUOTEThe lee collet die may not produce enough neck tension for an AR][/QUOTE]

I plan on using the fcd die to crimp the bullets so the neck tension should not be a issue.

Why?, because unless you have a match chamber in your AR
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rifle has a .223 Wylde chamber. It is a 24" bull barrel. It is a fairly tight chamber.

If you full size with .001 headspace will be better then neck sizing only even in your AR used for accuracy
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I will look into this as well. I will take some measurents of the fired cases and the full length sized cases.

I tried the neck sized cases in my S&W M&P 15 as well the bolt closed fine. I plan on giving it a try after my next range visit so I can mark the cases so I know for sure they came out of my rifle. It shouldn't be that hard. I will use rem cases and 99% of the .223 cases at my range are LC or some off brand stuff.
 
I have several "tight chambered" AR's and will assure you that sooner or later, you'll tie up your rifle with a case that ALMOST but not quite allows full lock up. When that happens, you're going to be kicking your own butt as you gingerly stick a cleaning rod down the bore of a loaded rifle to whack the stuck round loose.
Trust me, I'm not scared by many things but performing the described procedure makes me give strong thought to using only factory ammo instead of reloads.
 
Cases don't have head space, but neck sizing only for a semi is still a bad idea. Probably far worse for an AR that demands SB sizing to start with. Semi's do not have the camming strength a bolt action does, so no neck sizing for 'em.
 
Cases don't have head space,
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I know that and is why I added the word case to the term . I went back and read my post and could see how it could be read as saying head space only so I edited it . "case head space" has been used to describe the length of a case from head to datum line for many years if not decades . This has been hashed in every possible way .

. Hornady uses the term head space in describing that same measurement and don't even bother distinguishing the difference .
http://ads.midwayusa.com/product/47...4qnQdzGBFG9CM22tV_z864KuER3DA1YYG0aAnpO8P8HAQ

The Hornady Lock-N-Load Headspace Gage is a great tool for increasing the accuracy of your loaded ammunition. The Headspace gage measures from the case-head to the datum line on the case shoulder to allow proper brass resizing for a precise fit with the rifle chamber.
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Now if Hornady does not know head space is only a chamber measurement who am I to argue .
 
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I saw it attempted with an AR10 type .308.
We think the guy was advised by somebody who thought he had a bolt action.

He got to watch the rest of us shoot that day, because his rifle would not function.
 
Question here. twice now I have read you must use a SB die to size AR brass.
Why is that?. I just got mine about 4 Months ago now ( It is more of a Bench rest set up). I have put well over 600 rounds down it now. All Brass was previously fired in my Bolt rifle and sized on a Regular FLS Die. Never have had and issue. Chambers every round just fine with no problem.
 
I can't believe I'm the only one so far that thinks it's a stupid idea
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...No MetalGod, you are not alone in thinking that neck-sizing in a gas gun is a sure way to load the dice against you.
...twice now I have read you must use a SB die to size AR brass.
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No. But if you use unknown range brass -- or purchase surplus/military "once-fired" brass that may have come from a machine gun -- then you are advised to '1-time' SB size it to ensure base dimensions are normal from then on...
 
"MOBUCK. Learn how to "mortar" your AR so you dont accidentally blow your hand off."

I think NOT. I may not use the cleaning rod down the bore but I'm surely not going to use the "mortar" method. That may be acceptable in a combat situation but I haven't been there for decades.
 
4Runnerman : I've loaded a few thousand rounds for 4 different AR's and 3 different manufactured chambers . None have I used a small based die on . They have there place for sure , I'm just glad I've not needed one yet .
 
Metal-I am with Ya there, I have 2 SB dies now that do nothing other then sit on the shelf and collect dust. I needed one of them when I went from a stock barrel to a Custom Super Match Barrel. Have not needed them since.
 
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