Somethings up with my 5.56 reloads

[karnaaj]

I've been reloading 5.56 for 7-8 years now and up till recently it's gone well. But now I can't get my recent reloads to chamber in any of my 5 AR's. The bolt won't close all the way and the rifle locks up to the point that I have to mortar it to get the cartridge out. It doesn't happen every time but 3 out 4 tries its no good. I haven't changed out anything in my setup but I'm guessing the brass isn't getting resized properly. Any suggestions?

 

[murf]

trim the cases back to minimum and make sure your sizing die is fully sizing (not partially sizing) the cases.

murf

 

[BUGUDY]

I had that problem once with 6.8. I got screwed up between using carbide vs steel sizing dies and set the steel sizing die the same as a carbide, which did not fully size my brass.

 

[VoodooMountain]

Trim to length

Check shoulder (meaning your die may need to be re-adjusted)

Make sure your ram is coming up all the way and your brass is being fully sized. Sounds simple but I've had a couple of lee dies that were quirky.

Check your ejector and make sure it isn't hanging up. I would only expect this on a new bolt but you never know.

Get a case gauge as well

 

[joem1945]

Second checking case length. Also check the extractor to see if it's gets bound up, maybe remove it for closer inspection. Did you change bullet manufactures or type , style of bullet? I trim all my cases to 1.550 and have no problems with chambering.

 

[rcmodel]

Crimp buckling the shoulder is the usual cause.

Completely color a round that stuck with a black marker, and try to chamber it again.

Where the black rubs off is your problem.

I'd almost bet you are over-crimping with the seating die.

(If you crimp with the seating die, either on purpose, or by accident, every case must be trimmed to the same length, or the long ones will buckle the shoulder imperceptibly and lock up the gun.)

rc

 

[moxie]

And, of course, there's no reason to crimp 5.56mm used in an AR anyway. So if you are crimping, try not crimping.

 

[karnaaj]

I do crimp with a Lee FCD but maybe I am crimping a little with the seating die. I'm going to try a sharpie and see what happens.

 

[karnaaj]

OK. I just blackened two cartridges. One that chambers properly and one that doesn't. They both came out looking the same. I got my calipers out and measured every conceivable dimension and they all came out to within 1 or 2 thousandths of each other. I'm at a loss.

 

[murf]

is any of the sharpie rubbed off the cases?

murf

 

[karnaaj]

A little bit right around the lower part of the shoulder all the way around.

 

[murf]

if it's at the body/shoulder junction, you aren't sizing the case enough, or the crimp is pushing this area outward. i'm not sure if these are loaded rounds, or just the sized case, so try chambering just the sized case with the sharpie coating and see if any rubs off, again, at the shoulder. if you are chambering a loaded round, delete the crimp and retry the sharpie test.

murf

 

[Hungry1]

OP, it sounds like you're having the same problem that I recently experienced. My cases weren't being resized properly. I had cleaned my resize die and didn't set it up properly.

http://www.thehighroad.org/showthread.php?t=774415


I recently purchased a Dillon 223 case gauge. Useful tool,

 

[GLOOB]

When the ram is all the way up with a case in the die, shine a flashlight through the side to see if the shellholder and die are touching.

 

[moxie]

And forget the crimp!

 

[steve4102]

It doesn't happen every time but 3 out 4 tries its no good. I haven't changed out anything in my setup but I'm guessing the brass isn't getting resized properly. Any suggestions?

If you haven't changed anything, you are correct, you are not sizing completely.

How can this happen you say, I haven't changed anything?

AH, but you have, you have changed your brass. Not physically, but metallurgical.

Repeated firings and sizing causes Brass to become harder and stiffer. This is called "Work Hardening". Work hardening cause the brass to "spring Back" after being sized. So what is sized will not remain sized and will spring back.

There are a couple solutions for "work Hardened" brass.

One is to adjust the sizing die deeper into the press to compensate for the "spring back".

Another is to Anneal the case mouths and bring the brass back to it's original softer state.

Or you could scrap your brass and start over with softer brass.

 

[karnaaj]

When do you guys do your trimming? After resizing or before?

 

[steve4102]

Always after, always. The case will grow after sizing. Trim after it grows, not before.

What manuals do you have?

 

[karnaaj]

I have the Lee, Hornady and Speer.

 

[GLOOB]

You have reloaded 223 for 7-8 years and you don't know how to trim rifle brass? Time to start reading those manuals.

 

[HKGuns]

I highly doubt trimming is your issue. I've never encountered a piece of brass that was too long to chamber. Take your sizing die down another 1/2 turn and get a case gauge to check your brass.

 

[Kaldor]

I highly doubt trimming is your issue. I've never encountered a piece of brass that was too long to chamber. Take your sizing die down another 1/2 turn and get a case gauge to check your brass.

That may be, but I think Ill trim after sizing with every firing. Once you get setup for it, it doesnt take that much extra time. Id rather do that than replace a rifle, or an eyeball...

I run my sizing die bottomed out on my shell plate, then back it off a 1/4 turn.

 

[W.E.G.]

You must use a CASE GAGE to measure the dimension of the base of the cartridge to the shoulder of the case.

Otherwise, these and other problems will always haunt you.

 

[GLOOB]

I run my sizing die bottomed out on my shell plate, then back it off a 1/4 turn.

There's your problem. For most sizing dies, you're supposed to bottom it out, and then turn down an additional 1/4 turn. This is because when there's an actual unsized case in the die, it stretches the press, creating an unwanted gap between the shellholder and die. The force of sizing a rifle case is so variable (workhardening, fired size, amount of lube) that the only way to get consistent sizing is to have this hard contact. (Some folks partial resize with a floating die, but this only works with matched headstamp cases fired from the same gun, and it usually requires some fine tuning or annealing as those cases are fired a bunch of times). Some brands of older straight wall carbide pistol dies are supposed to be floated else the carbide ring might crack or fall out. But there's no headspace to worry about in a straight wall cartridge. Essentially all steel rifle dies are supposed to get hard contact between the die and shellholder.

Since you're floating your die, you are partially sizing. And when your brass gets work hardened, it is getting longer, yet, due to the compounding of press flex and work-hardening. Getting hard contact between die and shellholder takes out most of this variability, leaving only a little bit* of springback to provide variation in your cases. If you're shooting a bolt action and using only your own cases, you might want to just tweak your die down a little farther until things work. But if you're firing an autoloader and/or using mixed brass, just set your die for FLRing, correctly. If you do the flashlight check I suggested, you can verify that your die is set, correctly.

*It is only a little, so long as you are using cases that are fired from guns that are in spec. If you try to use cases fired in an out of spec chamber or machine gun, you can still have issue of hugely out of spec cases after FLR, due to a crazy amount of springback that can occur.

If you have a lot of ammo to fix, you might consider getting a body die.

 

[moxie]

Absolutely!

RCBS states adjust steel rifle dies 1/8 to 1/4 turn AFTER the die bottoms out. This should give you a "pop" or cam-over when the press lever is all the way down. This takes the play out of the system. This is the only way you're going to size a case completely. Backing the die off is backwards.

You don't have to trim after every firing. Not every case grows every time. You should MEASURE each case after sizing to see IF it needs trimming.

SIZE>MEASURE>TRIM (if needed)