Sanity Check - AR Headspace Issue

[CuddlyBear]

Hey guys, having an issue with a new AR-15 I just put together and wanted to run it by the community.

Mods - feel free to move this to the reloading sub if you think that's a better place for it.

The gun-
Anderson Lower/Aero Upper
Ballistic Advantage 18" .223 Wylde 1/8 Fluted SPR Barrel, rifle gas
PSA Premium BCG (HPT/MPI)
A2 stock/rifle-length receiver extension and rifle-size buffer

Factory .223 ammunition, in this case Wolf Gold .223, chambers and runs fine.

My .223 hand loads are giving me an issue. They are mixed headstamp brass, 24gr of H335 under a 55gr Hornady FMJ at 2.200" and a S&B SR primer. This load runs just fine as a light plinking load in all my other rifles with 5.56 chambers and my mini-14 (.223).

I had several hand loads that either refused to chamber or chambered with resistance in the rifle in question. After shooting I noticed an abnormal/excessive amount of brass buildup on the bolt face, and some of the spent brass had rings around the shoulder. Several cartridges in particular wouldn't chamber at all - I set these aside and measured them when I came home from the range. I observed that the top of the shoulder of the case, measured from the case head, was about .01" longer than the spec listed in my Lyman 49th edition manual. The rounds in question chamber and cycle freely by hand in my 5.56 chambered rifle.

I observed that this particular BCG from PSA has a thicker than usual phosphate coating.

My theory is that, for one, I did not adequately set the shoulders back on these cartridges when reloading them. This is being compounded by the tighter chamber in this particular gun, and the thicker phosphate coating on the bolt slightly reducing overall headspace.

My plan of action is to:
1. Allocate my stock of these handloads to the rifles that chamber it normally, and stop shooting them in this gun
2. Purchase a .223 case gauge and check my brass that will go into this gun going forward


Is this the right approach? Is there anything I'm missing here? Am I going to blow my hands off? Is shrimp the worst top ramen flavor?

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[KKG]

First off, because of the design there shouldn't be a head space issue. But there is something wrong and it seems to be head space related. Are you using small base dies? You might want to stick with a single batch of brass for use in this gun. Making everything the same couldn't hurt. It'd think about getting a Head Space Gauge SET before I'd mess with a case gauge. That's my suggestion.

 

[Geardo]

ARs CAN have headspace issues. Especially in lower teir components. Sounds like yours is just too tight. Worth it to buy some gauges or find someone who has em.

My 2nd AR was too tight.

 

[CuddlyBear]

I am using regular, not small base, RCBS .223 dies. As far as getting a set of headspace gauges, do I need Go, No Go, and Field? Or would just picking up the Go and No Go gauges be sufficient?

I've not tried swapping the bolt for a different one to see if that changes it, either, but I suppose doing any of that without headspace gauges is just a guess.

The PSA bcg is low tier but the barrel is certainly not... my understanding is headspace is mostly set when the barrel is pressed into the extension. Maybe I could take some 400-grit to the bolt face and knock a little of the excess phosphate down?

 

[Geardo]

The PSA bcg is low tier but the barrel is certainly not... my understanding is headspace is mostly set when the barrel is pressed into the extension.

In my headspace issue, the bolt face to lugs dimension was off, and causing the issues. The .223 wylde chamber was fine. I measured the dimension myself twice, and it was confirmed by the MFG, who promptly replaced it.

 

[308]

Are you using a full resize die for your brass? I had problems using the wrong dies for both .308 and .223 where what you described happened.

The M1A was especially sensitive to my reloads and I ended up with a few of those notorious pigpiles

 

[CuddlyBear]

In my headspace issue, the bolt face to lugs dimension was off, and causing the issues. The .223 wylde chamber was fine. I measured the dimension myself twice, and it was confirmed by the MFG, who promptly replaced it.

That is interesting. Do you have a resource you can point me to for the correct measurements?

 

[CuddlyBear]

Are you using a full resize die for your brass? I had problems using the wrong dies for both .308 and .223 where what you described happened.

The M1A was especially sensitive to my reloads and I ended up with a few of those notorious pigpiles

Yes, full length sizing with a standard .223 die

 

[Member 34319]

Are you trimming your brass to correct case overall length prior to loading?

Overall loaded case is one thing, but if your unloaded overall case is too long, you will have problems chambering that round.

 

[Geardo]

That is interesting. Do you have a resource you can point me to for the correct measurements?

Last time I just poked around on google images. Nothing official. Can't seem to find it now. Best bet is probably to measure against the other bolts you own.

 

[Stomper]

Try a different bolt from another AR to see if the problem persists before tearing apart everything else.

 

[CuddlyBear]

Thanks for all the replies.

My process is to set my calipers to the max allowable length for the cartridge OAL, and use that as a go/nogo for trimming. So, anything over max gets trimmed to 1.75. The ones I measured were within .01 of that from case head to mouth.

I will give some other bolts a shot in the rifle tonight and see if that changes anything.

 

[oli700]

Try a different bolt from another AR to see if the problem persists before tearing apart everything else.

this is the logical answer at this point ....

 

[Mygrainman]

I'm willing to bet it's a sizing issue. I ran into the same thing before I switched to a small base sizing die. You must get one of these..they are less than $20 and on the shelf at most big box.. you'll use it a lot more often than go/no-go's.



And get ready to pull and resize some brass. I have several hundred to do myself.

 

[DirectDrive]

Hey guys, having an issue with a new AR-15 I just put together and wanted to run it by the community.

Mods - feel free to move this to the reloading sub if you think that's a better place for it.

The gun-
Anderson Lower/Aero Upper
Ballistic Advantage 18" .223 Wylde 1/8 Fluted SPR Barrel, rifle gas
PSA Premium BCG (HPT/MPI)
A2 stock/rifle-length receiver extension and rifle-size buffer

Factory .223 ammunition, in this case Wolf Gold .223, chambers and runs fine.

My .223 hand loads are giving me an issue. They are mixed headstamp brass, 24gr of H335 under a 55gr Hornady FMJ at 2.200" and a S&B SR primer. This load runs just fine as a light plinking load in all my other rifles with 5.56 chambers and my mini-14 (.223).

I had several hand loads that either refused to chamber or chambered with resistance in the rifle in question. After shooting I noticed an abnormal/excessive amount of brass buildup on the bolt face, and some of the spent brass had rings around the shoulder. Several cartridges in particular wouldn't chamber at all - I set these aside and measured them when I came home from the range. I observed that the top of the shoulder of the case, measured from the case head, was about .01" longer than the spec listed in my Lyman 49th edition manual. The rounds in question chamber and cycle freely by hand in my 5.56 chambered rifle.

I observed that this particular BCG from PSA has a thicker than usual phosphate coating.

My theory is that, for one, I did not adequately set the shoulders back on these cartridges when reloading them. This is being compounded by the tighter chamber in this particular gun, and the thicker phosphate coating on the bolt slightly reducing overall headspace.

My plan of action is to:
1. Allocate my stock of these handloads to the rifles that chamber it normally, and stop shooting them in this gun
2. Purchase a .223 case gauge and check my brass that will go into this gun going forward


Is this the right approach? Is there anything I'm missing here? Am I going to blow my hands off? Is shrimp the worst top ramen flavor?

Very common to have this happen when trying to run reloads through several different rifles.
Each rifle is an individual.

It is rare to have a headspace issue with an AR but I always check them for my peace of mind.

If I had to run mixed brass between rifles, I would use a small base sizer die and full length re-size every time.

There are some differences between .223 and 5.56
Make sure you understand that.

 

[DirectDrive]

AR15 Headspace Data

New Rifle Headspace: 1.4646" to 1.4706"
SAMMI headspace gauges to use: 1.465" and 1.470"

Unsafe Rifle Headspace: 1.4736"
Use the Colt M16/AR15 Field Gauge: 1.4736" or,
The US military gauge: 1.4730"

 

[ron]

Common reloading problem with ARs and M1As. The shoulder of the brass is
not sized to spec. You should be able to chamber and remove the round with
no resistance. Measure your sized brass and adjust the sizing die to bring the
reading to less than "0" with a RCBS Precesion Mic. I use a standard RCBS
full length sizing die. Die might be adjusted to 'cam over'. The RCBS Precision
Mic can be used to measure brass or loaded ammo. Measure the brass before
and after sizing.

https://www.brownells.com/reloading...n-mic-cartridge-headspace-tool-prod33476.aspx

 

[CuddlyBear]

The bolt out of my carbine gives me the same results as the bolt in the rifle at issue. I definitely think this is an ammo problem at this point and will be working up some loads specific to this rifle going forward in addition to picking up some of the told and gauges mentioned here. Thanks again!

 

[v0lcom13sn0w]

when in doubt, small base or full length die.make sure you "cam over."also try factory ammo.

MY ars dont like neck sized brass.

 

[DirectDrive]

The bolt out of my carbine gives me the same results as the bolt in the rifle at issue. I definitely think this is an ammo problem at this point and will be working up some loads specific to this rifle going forward in addition to picking up some of the told and gauges mentioned here. Thanks again!

Assuming the AR is 5.56. is the other rifle chambered in 5.56 as well ?