Primers not seating?

[mmelnick]

I just loaded up a batch of 7 mag rounds using Federal magnum primers. I noticed that the primer actually sits back farther than the end of the shell casing. If I set it on the table the primer will hit the flat surface before the casing. It is only sticking out by a hair, but I tend to send the bolt home pretty hard to ensure consistency. I'm worried that I might set the round off while chambering.

I will obviously only chamber a round at the range with the gun pointed in a safe direction. But I would also like to know if this is normal with magnum primers. This is my first time using them.

The round on the left in this picture is an unfired factory round. You can see how the primer is fully inside the primer pocket. The one on the right is how mine came out. It's hard to tell in the picture but it is not fully inside the pocket. Is this normal or safe?

[Swampman1]

Unless my eyes are deceiving me, the one on the right looks flush, the factory one looks deeper than normal. But if the primer hits the table first...not seated deep enough.

[jwrowland77]

If the primer is hitting table first, seat the primer a little deeper.

I load for a 7mm RM also, and first time, noticed I really hard to squeeze the hand primer, but if all the way in, you can feel the anvil set. It does take a little pressure, but as long as you seat the primer slow and easy, you'll be good.

[mikld]

Normally I don't eyeball, or measure primer depth. I just make sure the primer is all the way to the bottom of the pocket. I can tell by "feel" when the primer is seated. And yep, if the case wobbles when set on the head, it's too high...

[mmelnick]

The photo looks flush, but it's not. It's just BARELY protruding. It did feel like it seated all the way. And all 20 that I loaded up are exactly the same. But yes, it rocks on the primer when I sit it on the table.

I wonder if this particular type of primer just won't work with these particular shells. The shells are reloads of the cheapest factory ammo I could find.

Maybe these casings just can't accept magnum primers. I'll have to get out the calipers and measure the depth.

Is it safe to try and shoot therm as is?

[snuffy]

All this, and we still don't know anything about the equipment being used to seat those primers.

Lot's of reasons why thet're not seating below flush. The reason you suspect is NOT the reason, a magnum primer is NOT taller or thicker than a standard primer. You're simply NOT applying enough force to seat them deep enough.

Oh, and the bolt will NOT fire a primer that's out too far. That's what the firing pin is for, a sharp blow in the center of the primer cup.

[cw308]

Do you use a uniformer on your primer pocket. I use a uniformer every time to clean the pocket and haven't had a problem seating primers.

[mmelnick]

To answer your questions...

It's an RCBS press with an automatic primer feeder. And no, I was not using a uniformer. To be honest I've never even heard of one. I'll look into it for sure though.

[Rangefinder]

Several things come to mind.

IF you're using NEW brass, they could have shallow pockets slightly out of spec. Judging by the photo, if that's the case, it's not a problem. Just use a uniform-tool next time you load them to square up any possible nubs, burrs, etc in the bottom before priming.

IF it's not new brass, try running them through again to snug them up where they should be. If you aren't seated all the way, the impact of the firing pin will be partially absorbed by the force seating the primer and you'll get possible light strikes resulting in misfires.

[William T. Watts]

Those primers are yellow unless my eyes are lying, all my federal primers are stainless/white (match, large Rifle and large Pistol! I have used Winchester and R-P in the past that were yellow.. This would be a classic case (no pun intended) for uniforming primer pockets, I use a Sinclair tool in a small electric drill! William

[snuffy]

http://www.midwayusa.com/product/338...mer-tool-large

This one is for rifle only. It would cut a large pistol primer pocket too deep,(because rifle primers are a little bit taller).

If you're using that RCBS press to prime, be sure it's mounted to a stiff strong table, that table has lots of weight, (or it's bolted to the floor), then put some muscle into priming those cases. Or grab the back of the press with your off hand to brace it, then pull your hands together. Don't worry about "setting off the primer". A steady pull on the handle will NOT set off a primer. Slamming the handle however, might!

[243winxb]

I use this RCBS priming Ram http://www.midwayusa.com/product/416...m-priming-unit

[m&p45acp10+1]

I concur what snuffy said. I will add that a hand priming tool would be a good investment to make. The Lee AutoPrime XR with the shell holder set can be had for under $45 from most places. The other work as well, and cost more. Though I would advise getting one. It makes priming much easier. I have been reloading with one since 2008. I would not want to be without one now. I do not use mine much anymore since I now have Lee Classic Turret press with a primer feed system. Though I do still sometimes use the hand primer for my rifle calibers that I have already sized/decapped, and trimmed, as well as tumbled off the case lube. I do this becasue those rounds get loaded single stage batch style.

[mmelnick]

Cool, thanks for the info guys!

[David Bachelder]

Did you try to chamber them? If you have proud primers there's a chance the bolt wont close. I have had this happen before.

[mehavey]

The Lee AutoPrime ...makes priming much easier.

+1 ...AND you feel the primer seat home exactly.

See also the RCBS Universal Priming Tool used as well.
What you pay extra at the start is saved in not having to buy shellholders.

[GeauxTide]

If the cases have been fired, I use the RCBS primer pocket tool to scrape out the residue that the case cleaner didn't get. I also use a Lee Primer Seating tool

[JimDandy]

If you're using that RCBS press to prime, be sure it's mounted to a stiff strong table, that table has lots of weight, (or it's bolted to the floor), then put some muscle into priming those cases.

I can reiterate this. I just did 100 rounds of 45 Auto on my Ammo Plant. Had 5 cases not get primed because of the "bench" I'm using. I thought it would work out pretty well to put it on a wheeled table and just lock down the wheels. But the wiggle as the locked wheels rotate around, not even roll is enough to throw off the extra "oomph" on the downstroke to not seat a primer if you don't work twice as hard at it. I'm about ready to either dump the wheels and find a cart I can put on and off the bottom when I want to move it, or get rid of the wheeled idea entirely. For now, I'm going to start priming by hand.

[stubbicatt]

+1 on the recommendation to get a hand priming unit, or a dedicated RCBS bench mounted APS unit. I really like the APS priming, both because the primer strips advance automatically to the next live primer, the primers never get cocked or seated upside down, and because the plastic strips strike me as safer than loose primers on a tray in the unfortunate event that the one being seated should detonate.

[Colorado Redneck]

Seating primers correctly can be frustrating. Using the primer attachment on a Rock Chucker didn't always get the primers seated correctly for me, no matter how much oooomph I put into it. Primer Pocket Uniformer solved my problem with 38 Special brass.

With the RCBS hand priming tool, I can squeeze the handle till it will go no further (use both hands) and sometimes (rarely) still have a primer seated too shallow. Perfection is unachievable, in me estimation.

[mehavey]

Perfection is unachievable...

Not according to my wife.
I'm her un-ending challenge.

[mmelnick]

Everything came out better in my next batch. Thanks for the tip about the uniformer.

[cw308]

Seating primers isn't hard when you uniform the primer pocket, I'm glad you didn't use more force to seat the primer. Primer should bottom not jam in position. Be safe Chris

[hooligan1]

I always clean primer pockets thoroughly before I prime. I use an RBCS hand prime tool, CCI 250 primers is the only primer I use for the Magnificent 7..., And I've never seen any problem.... the photos dont show enough to reach out at me..... just make sure when you prime the primer goes All the way Home.