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Old 05-13-2011, 05:06 AM   #1
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Primer seating depth....

I have always wondered when I seat new primers in their pockets why some seat deeper than others. Do the pockets vary in depth that much from mfg. to mfg. ? Do the primers vary that much in thickness? Do the pockets sink as you reload them more and more? Sometimes they are so deep that the firing pin stikes them but not deep enough to ignite them. Is it a combination of all the above?
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Old 05-13-2011, 07:07 AM   #2
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Re: Primer seating depth....

Well, Mr. Wolf, you're going to have to be much more specific because I don't see that at all.

It is surely true that there are variables in all the components but I've never seen a primer pocket "sink" to any degree to be noticeable.

Give us some examples of all the components you're using, caliber, load, etc. and we'll try.

It also occurs to me that putting a large pistol primer in a large rifle pocket will do that.
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Old 05-13-2011, 11:23 AM   #3
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Re: Primer seating depth....

Mr. Petty
Most of the pistol ammo is .45acp and 9x19. I use various brands of brass, Rem., Win., S&B, Fed. etc. I vibra-clean them in walnut and use RCBS carbide dies. I NEVER use rifle primers on my pistol cartridges or vise versa. Primers are usually CCI or Winchester. My loads are NEVER MAX. or HOT. I usually stay 20% below MAX. or use beginning load listed. If you need even more specifics let me know. Thank you.
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Old 05-13-2011, 01:47 PM   #4
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Re: Primer seating depth....

All of that sounds just fine.


While you will see some variation in both pockets and primers it shouldn't be enough to cause misfires.

If you have a dial or digital caliper you can measure both of those elements. I'd also suggest saving any misfire cartridges to see if a make of brass or some other thing is a constant. Carefully disassmeble those and measure etc.

Check your primer seating operation to be sure there isn't excessive force. Normally the primer should be slightly below flush
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Old 05-14-2011, 05:10 PM   #5
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Re: Primer seating depth....

"...usually stay 20% below MAX. or use beginning load..." Hi. You don't have to do that. You should work up the load for a handgun using data from your manual. That's how you find the most accurate load for your pistol. A starting load or 20% below max may or may not be the most accurate. Accuracy being the purpose of reloading. Helps that it tends to be less expensive as well.
Primer pocket dimensions are set to SAAMI specs. Primers are all the same size(a Large pistol from CCI will be the same dimension as a Winchester), but some cups can vary in thickness. Rarely makes any difference though.
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Old 12-30-2011, 04:42 AM   #6
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Canis Lupus/ Charlie I too have noticed differences between some cases and others with the same primers. The industry likes .004" below case head last I heard.

I have seen more brass that was not deep enough in the pocket dimension and I had to use a Sinclair primer pocket uniformer to recut the bottom of the primer pockets on some 308 cases to get the primers to seat below the rims.

It strikes me that you might not have enough striker protrusion which should be at least ..040" to .060 and I have seen encased strikers not protrude because of glass blasting dust build up inside the striker bushing on a Ruger revolver.

Next off you didn't tell us if you are using revolver/ rifle or????

I have also seen another condition where a primer gets blanked and a disc is dislodged from the primer and go into the striker opening and prevent the striker from coming forward. This is generally caused by a weakened striker spring where it still has enough energy to set it off but not enough to hold the primer in during the pressure curve peak reading.

I had this happen on my 7615 or almost did. I was having M193 primers wanting to reverse flow into the striker opening. When I sent rifle in I told them about it and they did not change it so when it got back I got Wolff hammer springs and replaced it and now have striker energy higher than M16/M4 specs! ! ! ! No more reverse flow either.

As well Gruenig and Elmiger rifles no longer come with large diameter strikers for the medium bolt face guns. The reason being the 6MM BR uses small rifle primers and the large striker was getting blanked primers at a high rate so they went to small diameter striker nose dimension and the problem went away immediately. A G&E has a tremendous striker spring design.

As well looking at a indent on a unfired primer does not tell the story as we are all used to looking at fired primers.

Also what is your misfire rate in say 500 rounds?

Last edited by Hummer; 12-30-2011 at 05:24 AM.
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Old 12-30-2011, 05:13 AM   #7
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Hummer,

i'm wondering if his striker spring and/or firing pin length may be so marginal, that any deviation in fodder causes some FTF????

yours, sw
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Old 12-30-2011, 05:30 AM   #8
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Could well be. Very few folks know how to check striker energy and even fewer have the tools to do so.

I have the tools for 5.56, 308 and 30.06. Last holder I bought was like 2002 and it was 160.00 if I remember correctly.

Also the gage material was like a buck each 30 years ago. fortunately I have a lifetime supply of them.

I have had three four new rifles in last 7 years or so that had insufficient striker energy new out of the box.

My rule of thumb is one misfire is way too many so I check my target guns at the start of the season to make sure the springs have not taken a set.

If you don't have the tools the cheapest way to it is remove striker spring as new and measure the free length and record it. At end of season do it again and record it. Can't say for sure but from what I see when they shorten about 1/4" the energy is marginal.

When I guy springs I always get the next higher energy level or the middle one Wolff makes. I don't replace with factory springs at all.
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Old 01-03-2012, 05:25 AM   #9
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Sheesh...the way these spammers keep popping up, you'd think they were getting some hits...
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