.223 reload malfunctions

[elwoodcg]

Problem:
I've had an inordinate number of my .223 reloads fail to fully chamber in my AR's lately (maybe 5-10% of the rounds). The bolt seems to strips the round off fine but the round fails to chamber fully (bolt not locked in battery). Hitting the forward assist doesn't help move the bolt into battery. I've been able to remove the stuck cartridges (live rounds) by pulling hard on the charging handle but several have been stuck to the point where they had to be mortared out.

Background:
I've been reloading for a couple years now on a turret press. Mainly doing low-volume loads with good bullets and Varget. I recently bought a Dillon 650 and am working up some "blaster" reloads with mixed brass, a mid-range load of TAC, and Hornday 55gr FMJBT bullets. I've never experienced this type of malfunction in my previous reloading. The new variables here are the 650 and the bullets. I doubt the bullets are the issue.

The primary rifle I've tried this load in is a DDM4V5 which has been 100% reliable with my previous handloads and several types of factory loads. I also tried some in a new DD MK18 and experienced some of the same issues but ran great on factory 5.56 ammo. Various PMAGS were utilized.

Observations:
I held onto 4 of the rounds that failed today. I checked them in a Dillon case gauge expecting the to be too long but 3 were definitely in spec and 1 was borderline on headspacing. OAL was fine on all rounds. The bullets themselves all have "bite" marks towards the tips like they've been gouged by the feed ramps or something. The bullets have cannelures but I don't crimp. Maybe I need a slight crimp?

Sorry for the long post. Any help figuring this out would be much appreciated.

[Steel head]

What is your case length?
Trimmed em recently?
Same dies in you 650 as before?
What do your fired cases measure in the case gauge leading to how far are you bumping the shoulder back.

I had a similar issue, it was longer than spec cases getting into the crimp area of my seating die which was set to not crimp with an in spec case.
I never crimped 223/5.56 myself.

[elwoodcg]

See preliminary answers below. Thanks.


What is your case length? 1.761, 1,761, 1.762, 1.760.
Trimmed em recently? No. These are once fired and passed a case length gauge.
Same dies in you 650 as before? Yes. RCBS small base .223 dies.
What do your fired cases measure in the case gauge leading to how far are you bumping the shoulder back. I'll post after I measure some of the spent cases.

I had a similar issue, it was longer than spec cases getting into the crimp area of my seating die which was set to not crimp with an in spec case.
I never crimped 223/5.56 myself.

[sinister]

Your chamber is your ultimate chamber gage.

Clear the weapon and remove your upper from the lower. Will a round drop fully into the chamber, and when you raise the muzzle does it drop out on its own?

You've removed all case lube prior to firing?

[Tzed250]

My DD barrel and BCM bolt have what seems to me to be very tight headspace. After sizing LC brass so it was just below the long step on a Wilson case gage the rounds would not chamber reliably. I needed to adjust the die down to the point of a heavier cam over to move the shoulder back. With the brass sized to the short length on the case gage I've had reliable chambering.

[elwoodcg]

They do not appear to be fully chambering and I needed to bump the upper on the floor to get them to drop free. My 5.56 factory loads dropped right out. I think the shoulder dimension is too wide. All measure .356 vs the spec of .3543. My 5.56 factory loads measure around .347 at the shoulder. Does that sound like the culprit? If so, any recommendations on remedies? What would cause this?

[Steel head]

I would also ensure that your seating die is backed out enough not to crimp.


They do not appear to be fully chambering and I needed to bump the upper on the floor to get them to drop free. My 5.56 factory loads dropped right out. I think the shoulder dimension is too wide. All measure .356 vs the spec of .3543. My 5.56 factory loads measure around .347 at the shoulder. Does that sound like the culprit? If so, any recommendations on remedies? What would cause this?
My factory and resized is in the .350 range and fired cases .355 so either your dies need adjustment or are otherwise not sizing the case down enough or there may be some other issue.
Not sure if possible but maybe a hard seating bullet could open the shoulder dimensions.
I have shmushed a shoulder with a bad crimp.

[Colt guy]

My DD barrel and BCM bolt have what seems to me to be very tight headspace. After sizing LC brass so it was just below the long step on a Wilson case gage the rounds would not chamber reliably. I needed to adjust the die down to the point of a heavier cam over to move the shoulder back. With the brass sized to the short length on the case gage I've had reliable chambering.

This is what I also think is going on. In other words measure the shoulder and bump it back.

[elwoodcg]

I think I have this worked out, guys. After a bit of googling, I think the shoulder bulge is due to my seating/crimp die. I'll back it off and skip the crimp altogether. If I ever feel the need to crimp, I'll buy a Lee factory crimp die. This is all starting to make sense, especially after reading Dillon's logic on why a combo seating and crimp tie is a bad idea (opposing forces don't mix). Thanks for the replies.

[Steel head]

a combo seating and crimp tie is a bad idea (opposing forces don't mix). Thanks for the replies.

This, same for pistol or rifle.
I have a loaded round I keep that I shmushed the shoulder so much it looks like an 223 improved case.

[SWThomas]

Sounds like a sizing issue to me. Case gauges are pretty worthless IMO. A bump gauge and a digital caliper is my preferred way. A freshly fired case will drop right into a case gauge and look normal most of the time.

[GunnutAF]

Steel head
Well look like your trim length is to long! 1.760" is the MAX case length! Trim you case to 1.760" or below and yes .001" could be the difference between chambering or not! Especially if you have a tight chambered AR. Trim your case down to 1.755" and I'd bet money you'll have no more problems. Full length resize as well- as you should for all AR use.

[ramairthree]

if it is just one gun, I would say out of spec chamber. I have one 556 chamber for alpha sports or redx arms or something that came tighter than my 223 Wilde barrel.

I have also found the typical Wilson type gauges , while great for pistol rounds or oal on rifle bottle neck rounds, will let a lot of stuff slide on 556 and 300aac when it comes to shoulder tolerances. These shoulder issues, when ammo related, I have seen cause your symptoms if
Not enough lube, case,shoulder gets stretched out of spec on upstroke from sizing,
non FCC type crimping squeezing shoulder out too far diameter wise,
Previous good lots from your die, but dies has gotten a quarter, half turn or whatever loose and shoulder not bumped back enough

[Steel head]

Steel head
Well look like your trim length is to long! 1.760" is the MAX case length! Trim you case to 1.760" or below and yes .001" could be the difference between chambering or not! Especially if you have a tight chambered AR. Trim your case down to 1.755" and I'd bet money you'll have no more problems. Full length resize as well- as you should for all AR use.

My trim length is GTG, when I had issues like the OP I didn't check the cartridge I set my seating die with, it was an oddball shorty and when I started putting some in spec cases through it, SHMUSH SHMUSH SHMUSH was the end result.
I now have a dedicated case for setting my seating die.
Reloading lesson #1523 was learned the hard way as always.
Pistol dies for seating/crimping seem to have a mile of leeway compared to rifle dies in that respect.

[varmint49]

Small Base Dies will help when you are reloading for any Auto.

[elwoodcg]

Guys, as I stated a few posts up, this issue is resolved. Steelhead nailed it and Sinister helped too. I re-inspected all my loaded rounds and culled those with bulged shoulders. I backed out my seating die to ensure no crimp is being applied and it's working like a charm. Mods, feel free to lock this thread if you want since there seems to be a couple posts that don't relate to my particular issue.