Overseat primers?

[chamokaneman]

So I've been loading 9mm for a little bit now...probably not more than a hundred rounds or so. I bought a Wilson case gauge and while I believe its more for finished rounds I have been doing some checking to see if case dropped/didn't drop at different stages of the process.

On my first batch I had a couple cases at the end that just wouldn't quite drop all the way although they had dropped earlier in the process...seemed like something was going on with the rims. They plunked in my barrel OK so I shot them, no problem.

Yesterday I was working on a tiny batch and noticed on several they would drop after they'd been resized but not after I'd seated primers. I punched them back out and tried to resize them again but the last little bit of the rim wouldn't drop.

I prime with a Lee Handheld primer tool. Just wondering if anybody has ever found that seating too firmly can cause unwanted changes to the case head?

 

[Erief0g]

Not had that issue.

Occasionally need to wipe out case guage do to residual case lube and some possible powder kernels that might hold it up.

I only case guage finished cartridges.

 

[Demi-human]

Yesterday I was working on a tiny batch and noticed on several they would drop after they'd been resized but not after I'd seated primers. I punched them back out and tried to resize them again but the last little bit of the rim wouldn't drop.

I prime with a Lee Handheld primer tool. Just wondering if anybody has ever found that seating too firmly can cause unwanted changes to the case head?

Is there any debris or burr on the hand priming tool that could be damaging the rim of the brass?

I think Arnold in his prime could damage a piece of brass with a hand tool, but I seriously doubt any mere mortal could do it.
It may be putting a nick in the base, but it is not moving the size of the head.

I give the ‘ol priming tool a cleaning out too, when you make sure the gauge is clean and dry.

I would like to point out that, like you experienced, your barrel is the ultimate gauge. It passed them all, so are they really “not good”?

 

[CQB45ACP]

You say you are testing the cases at “different stages of the process.” What stages are they specifically? If the steps include after you have expanded but before you’ve seated the bullet and crimped, that would cause your problem. You might also have a bulge at the base and there may be other issues such as cleanliness, etc., but for sure that’s a showstopper.

 

[Ks5shooter]

Dirt build up in dies ,maybe? Cleaning a die can be a quick cheap fix.

 

[tightgroup tiger]

Check for very small burrs on the rim of the case. That's the only thing I can think of. Priming a case won't expand the head. It also won't keep it from dropping all the way into the case gauge. You may have had a small burr and the shell holder pushed it out sideways when you primed. I have a S&W 9mm that like to put small burrs on the rim, and because I use an ultrasonic to clean cases with, they don't get polished off.
I've found quite a few that wouldn't go in my gauge because of a small nick on the inside of the rim.
I keep a riffler file on my bench to fix them with.

 

[IALoder]

I've had something similar happen when hand priming. There was a sharp edge on the "shell holder" ( I use and rcbs universal hand primer) that would catch the case head and pull a little burr on the rim every once in a while. Look for sharp edges and knock em off once found. Haven't had a problem since.

 

[chamokaneman]

Lots of good advice. The main thing I was wondering about is if I could actual bulge the base a little by cranking on the primer too much. Sounds like no. I've never thought to clean my priming tool or check the shell holder.

 

[chamokaneman]

On the first batch I was talking about I did notice a nick on a couple rims. Kind of took them down with a little nail file kind of thing but they never did gauge. Just shot them anyway.

Always trying to learn a little more.

 

[Walkalong]

The main thing I was wondering about is if I could actual bulge the base a little by cranking on the primer too much

I can't see how.

Damage the rim some with a poor fitting shell holder perhaps. Using a Lee? They make two that "work" with 9MM, one fits much better than the other. You don't compete in strong man competitions do you?

 

[higgite]

The most common causes when I see what OP is seeing are:
1. A burr on the case rim, often caused by an extractor. No big deal.
2. Dirt or powder specs in the case gauge. A dry chamber brush usually cleans it up.

 

[mdi]

Anytime there is a fit issue, measure. Measure your case to see where it is too big. But in your case perhaps your "extra pressure" with the priming tool is warping/bending the rims. BTDT especially when priming on my Co-Ax. You have isolated when the problem happens so measure and closely inspect after priming (I have to "hard seat" Winchester SP primers to work 100% in one of my 9mm pistols and occasionally will bend a rim).

I had a similar problem with my Garand brass and a case gauge. I fought the problem for quite a while and even bought new sizing dies. It turned out the cases were hitting the Op Rod hump on their way out of the gun, just enough to stop the cases from fitting gauge, but they would chamber and fire well. Put the gauge away and use the plunk test now (yes you can plunk test rifle ammo).

 

[WestKentucky]

I need to buy case gages. I have some strange things happening with 7-30 and some of them just refuse to fit the barrel. I don’t think it’s priming doing it, but there’s something happening on the casehead.

 

[gifbohane]

I keep a dozen or so Q tips near the Wilson case gage that use at the end of the process. If a round does not seat I give the Q tip a few swirls inside the gage and 95 percent f the time it clears out the crap that was stopping the round from seating in the Wilson.

 

[bullseye308]

I keep a dozen or so Q tips near the Wilson case gage that use at the end of the process. If a round does not seat I give the Q tip a few swirls inside the gage and 95 percent f the time it clears out the crap that was stopping the round from seating in the Wilson.

If there is a burr or anything strange it will catch on the qtip and leave evidence. If everything is clean and smooth no fibers will be left.

As far as case gauges go, they are great for setting your dies close, then using the barrel to set them. If you have multiple of the same caliber, load for the one with the tightest chamber and all should be good. Or, like a few of us, I load for each specific pistol(6 different 9’s) for the best accuracy in each one. All my loads but one work in all of them, one is just tight and short.

 

[Riomouse911]

The Lee priming tool will break (or your thumbs will) long before you can damage a case head.

I will be buying my third Lee hand-prime in just over twenty years. Not made of the strongest materials, they do work well but will wear out eventually.

I agree with the others, it’s most likely crud inside the gauge.

Stay safe.

 

[chamokaneman]

I can't see how.

Damage the rim some with a poor fitting shell holder perhaps. Using a Lee? They make two that "work" with 9MM, one fits much better than the other. You don't compete in strong man competitions do you?

Never in any danger of a proud primer Definitely am gonna take a look at the sheller holder.

 

[CQB45ACP]

Never in any danger of a proud primer Definitely am gonna take a look at the sheller holder.

And what’s the verdict OP? Inquiring minds want to know the cause.

 

[hdbiker]

I bought an original Lee hand priming tool, with the screw in shell holders back in the early 70's. I used it so much I wore out the threads in the aluminum body. Was lucky to find a good used body at a gun show parts table. Back in business. I've been lucky to find all the shell holders I need To prime all the dozen or so calibers I reload. I still love and use to this day. hdbiker

 

[FROGO207]

I have the Lee screw in type, the Lee old style hand prime, a couple of ram primers, and the origional on press primers. Never have I been strong enough to bend or booger up a rim so that a case would not fit a gauge or chamber. Just sayin'. The brass might be expanded and not fit the gauge but if it chambers I use it.

 

[herrwalther]

You are more likely to crush the primer than distort the case head, especially using a hand tool.

 

[Klaatu Barada Nikto]

Check for very small burrs on the rim of the case. That's the only thing I can think of. Priming a case won't expand the head. It also won't keep it from dropping all the way into the case gauge. You may have had a small burr and the shell holder pushed it out sideways when you primed. I have a S&W 9mm that like to put small burrs on the rim, and because I use an ultrasonic to clean cases with, they don't get polished off.
I've found quite a few that wouldn't go in my gauge because of a small nick on the inside of the rim.
I keep a riffler file on my bench to fix them with.

This has been my experience as well. So much so that as I'm moving toward the case gauge I'm unconsciously running my index finger around the rim.

 

[chamokaneman]

And what’s the verdict OP? Inquiring minds want to know the cause.

I'm going to say it's burrs on the rim.

I was loading some more this evening and had 3 out of 50 that wouldn't drop that last little half/quarter thickness of the rim. They were at the upper end of the width a rim is suppose to be (.384-.394) but still within specs and I could feel the slightest little bit of burr also. Tried to roll the case rim around a bit I pulled the barrel I shoot them in right quick and they plunked in there fine so they're getting shot. Next time I need to a do a batch start to finish I may take more measurements and write things down better and come up with something better.

I did clean the case gauge with some alchohol and it was pretty dirty so cleaning it may have kept the numbers lower. That's going to be part of the routine from now on.

 

[chamokaneman]

Tried to roll the case rim around a bit

Tried to sand off the burr by rolling the rim on a piece of light sand paper a tiny bit but didn't seem to make any difference so I press on plunking them in my barrel

 

[CQB45ACP]

Tried to sand off the burr by rolling the rim on a piece of light sand paper a tiny bit but didn't seem to make any difference so I press on plunking them in my barrel

After going through all that, I just can’t imagine the rim’s the problem then unless you’re using some beat up old crap brass.

So let me recap for my own sanity...These are loaded and crimped 9mm rounds that won’t fully drop in a now completely cleaned case gauge but drop perfectly fine in your barrel AND you have in fact fired the offending rounds successfully in your pistol? You’ve got a bad gauge. Edit: that is of course a flawed conclusion. But, try this with your next round that doesn’t fit in gauge...turn the round just a little and try again and then again. I have two gauges Hornady and RCBS. Everything fits the RCBS almost everything fits the Hornady—when it doesn’t, a little turn always works telling me it’s....