Priming issue with .308

[SuedePflow]

I'm just recently getting into handloading .308. It's also my first time loading anything with large primers.

Anyway, I have my brass, sized, trimmed, chamfered, and cleaned. I decided to load my initial test rounds last night and ran into an issue with priming. I'm using CCI 200's and an RCBS hand primer (part number 90200). It's seating the primers way too deap. They seem to be sunk in about .025" below of being flush.

This is happening with Hornady brass and my LC brass. It's almost as if the rod in the priming took is too long. Can anyone else confirm the length of the larger priming rod in their RCBS priming tool? Mine is coming through at 1.875" long.

 

[ironworkerwill]

Deep is good.Too deep I don't know.... Pics? .004'' is good

 

[steve4102]

It's not the priming tool or the "rod".

Primers should be set to bottom out in the pocket.

If your primers are set to deep, then your pockets are to deep.

Did you uniform or remove a Primer crimp? If so, with what?

 

[notaglockfanboy]

The primers should set just below flush of the case head. Did you use a primer pocket uniformer on the brass?? If so , you may have reamed the pocket out too much. Do they fire in your rifle??

 

[SuedePflow]

Primers should be set to bottom out in the pocket.

If your primers are set to deep, then your pockets are to deep.

Did you uniform or remove a Primer crimp? If so, with what?

That makes perfect sense to me.

But the fired primers that are coming out of these cases are set perfectly. And I'm not doing anything that is deepening the primer pockets either. I did remove the crimp with one of these but it doesn't even touch the bottom of the pocket. I just don't understand how the pockets are too deep for these primers...

How deep should the primer pockets be? I'll measure mine tonight. As well as the thickness of the primers themselves.

 

[SuedePflow]

I also primed two LC cases last night without doing any prep on the pocket whatsoever, and had this same issue.

 

[Reloadron]

Well this is primer and primer pocket dimensions:



I would measure several cases and note the pocket depth. For large rifle you want between 0.125" and 0.132". Most of the cases I have laying around hit around 0.127" pocket depth which is average. Next measure your primer thickness, my CCI 200 are about 0.125. You seat a primer till it bottoms out so with what I have right now my primers would be about 0.002" to 0.003" below flush after a final push seating them.

Ron

 

[FROGO207]

Are they large PISTOL primers and just marked wrong?? The LPP is shorter than the LRP and putting them in a rifle pocket will show them to be short.

 

[ironworkerwill]

Yep, that looks most probable.

 

[30Cal]

I have to cut pockets to get primers to 0.010" below flush with my LC90 308 cases. If it's not the cases, it's the primers.


Is the 0.025" a measurement or is that eyeballing it?

 

[bangswitch]

Before loading a large lot, test fire a sample of these with the deeper-seated primers and see how they work. I'm betting they'll do okay. LC brass will have a slightly deeper pocket, the primers should seat at about the depth you measure; at least I get the same with the Winchester Large rifle primers on my LC 7.62 brass. Deeper is much better than too shallow; deep seating decreases the likelihood of slam-fires in autoloaders with free-floating firing pins.

 

[SuedePflow]

Well, I measured three random primers and three random pockets last night.

The primer pockets ranged from .124"-.127" deep.
The primers measured .124"-.126".

I also measured the primed cases to see just how far the primers are sunk in. They're weren't as bad as I originally thought. Most of them are .005"-.006" below flush. Is that acceptable?

The worst one was at .010" below flush. Here's the best pic I could get with my phone of that one:

 

[JimKirk]

Normal to me (.005"- .006")... my Forster Co-Ax seats primers .005" below flush ... unless there is a abnormal primer pocket ...

 

[ironworkerwill]

.005 is plenty good. Lyman's 49th says .004 is where you want it.

If you have .002 head space and are at .010 deep then your firing pin will need to travel .012 just to make contact with the face of the primer. Minimum protrusion should be bout .035, so with the deepest one at .o10 and min FP at .o35 would give you .o23'' impact depth(in a perfect world).

I think you are ok.

 

[gamestalker]

Well, since you measured how deep they're seated, and now know that we're only talking about .005" - .006", the only other thing to focus on is making sure they are completely seated to the bottom of the pocket.

The most important and pertinent factors in seating primers, are:

A. They must be completely seated to the bottom of the pocket

B. They should be seated to at least flush, but never higher than flush

GS

 

[ironworkerwill]

BTY, I also assumed you bottomed them out.

 

[SuedePflow]

Thanks for the assistance, guys. I'll try to get out this coming weekend to test some of these initial loads to make sure everything fires OK.

 

[30Cal]

Think you're going to be just fine.