Primer Seating

H4831

H4831

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At the range there was the odd one of my 45-70 loads that the Marlin lever would not completely close on. At home I measured everything about the cartridge, couldn't find any reason why it wouldn't completely chamber.
Then noticed a very slightly protruding primer on the two that wouldn't seat. Pull the bullet, dump the powder, close my eyes and give the primer a solid push on the press. Primer in, reload and at the range it went in OK and fired.
Noticed it takes extra push on the press handle every time to seat the primer completely flush. Even with all this extra care, had one more the lever wouldn't close on. Very slightly protruding primer. Remembered that all of my earlier loads were loaded light and I used large pistol primers. Didn't have this problem.
So, started measuring things. Win large pistol primers are .119", top to bottom.
Fed. large rifle, which I have been using, are .127" high.
CCI large rifle mag, .125".
Used the tail of the digital calipers to measure the depth of primer pockets in cases.
W-W 243 case, .126 deep.
30-06 Federal case, .127 deep.
New Remington 45-70 cases, .115" deep! Meaured several, all same.
Don't think this is only Remington cases, either. Have some "no name," just the two stars on the cartridge face, connected with an arc. Didn't have one available to test at the moment, but they were the first that wouldn't completey seat in the Marlin, so quit using them.
We always say to test every cartridge in the chamber, before going on a hunt or a shooting match. But, the aggravting part of this is that I can only test them in the chamber at the range. By leaving the action open, one can safely drop the cartridge in the chamber. When it hits bottom with a sharp clunk, you know it goes in the chamber and tipping the rifle up will remove it. But with the protruding primer the cause, one must close the action completely, seeing that the lever fully closes. This is altogether too dangerous to even think of doing in the basement, so is done at the range.
The rifle seems so tight on headspace that a primer protruding so slightly that it can oly be detected by sliding a sharp edged instrument over the case head to check, will find it. In other words, I visually inspect every primer, but even so, have missed seeing one or two that wouldn't load.
It seems amazing that the primers I am using have to be compressed about .o13 to properly seat.
Has anyone else encountered anything like this?
 
My pistol brass do that some times.
But, unlike you, I'm no expert. On my Dillon, when primers arent seated correctly, I can't index further (550B) so that's a big help. When it happens I just press harder, not extremely hard though, don't want a blown primer in such a consrict place (Also doing this in the basement, in the furnace room actually)

When it happened the first time, I deprimed the brass and cleaned the primer pocket, I thought that could be the culprit, but it didn't do any better. Also, my pistol brass is mixed and I've had this happen to several headstamps.
2 stars brand like you
some military brass
federal
winchester

I haven't kept track of it so I don't know if a hard to prime brass does it everytime, but I know it happens frequently
 
This has somewhat happened to me with Fed NT brass and IVI brass. Before I knew to swag the pockets I have gotten a few primers mangled in the primer pocket, which subsequently jammed in my lee hand primer. The only way to get it out was by really squeezing hard to get the primer to seat (very carefully of course) but I have never had one go off.
 
H4831; No I haven't encountered that with RP or WW 45-70 brass. I just went down and measured some of mine to see how they compare to yours. The pockets on the several of each I checked measure .127 close to the edge of the pocket side. It appears you may have some brass that is out of spec for pocket depth is my best guess.
 
H4831: You mentioned you had previously used large pistol primers which I also do with select light loads; that is, round ball at velocity well below 1000. I have to wonder if the primer pocket could set back to match the pistol primer if presure was adequate to move the brass. You might make a guess at that knowing what your previous loads were. I have kept my round ball brass separate from brass used for higher pressure loads as I do not resize the round ball brass. I don't have any of that brass in a discharged state to measure it to check for set back.
 
The height of a primer includes a protruding anvil, which will be lowered until it is flush, when it gets seated.

Still though, the primer pocket in that brass is way too shallow - surprising! A primer pocket uniformer would clean that up, if you like buying lots of extra tools.

I make a point of running a fingertip over the primer, to confirm by feel that it is properly seated to below flush. It takes very little practice to get a good feel for a primer that is proud (protruding), flush, and properly seated several thou below flush.
 
BIG, BIG SURPRISE!
Have now checked the 45-70 brass with the two stars and arc. The depth was .131! I originally had two of those that wouldn't load, but it is obvious it wasn't because of primer pocket depth.
My Remington are obviously away out of the tolerance range. I guess it is time to contact Remington.
And Stocker, all of my 45-70 loadings are actually very low in pressure, well below the range of large pistol primers, so I could use them. One favourite load for general shooting, with the 420 grain bullet, is 33 grains of 4198. This is listed as probably under 20,000 cup. The speed shoud be maybe 1450 fps.
Another, at about 1600, is 45 grains of 4895. The pressure on this one is likely about 28,000. Even this low pressure will give the bullet a muzzle energy of about 2,400 foot pounds. By the same token, I load the 44 magnum with pistol primers, for loads that are 38,000 to 40,000 cpu.
 
The brass with 2 stars and a line are...............Starline!
I have 500 of them in .45/70 and when primers are seated (WLR) they are averageing .008 below the case. I haven't had one fail to go off yet.
 
The Starline brass I have used has pretty snug primer pockets. The Winchester primers seat pretty easy but I have found CCI and Federal require a bit more pressure to seat properly. I have never tried Remington primers in them.


H4831. The Starline brass also may not be the best choice for low power 45-70 loads. They designed these cases for stout loads and on their website warn that they may fail to fully expand to chamber diameter unless the case mouths are annealed to soften them a bit.
 
H4831: You are probably correct regarding set back of the cup bottom of the case. But, the deeper cup on a rifle primer tends to support the bottom of the case a bit leaving no room for movement. The 44 mag case has the shallower cup I believe so it wouldn't be a direct comparison. It was a thought that may have no basis in fact- I don't really know. I do think your RP brass is out of spec either as made or????
 
'Boo said:
H4831. The Starline brass also may not be the best choice for low power 45-70 loads. They designed these cases for stout loads and on their website warn that they may fail to fully expand to chamber diameter unless the case mouths are annealed to soften them a bit.
Click to expand...


The best load that I've found with 405 grain cast bullets is 32 grains of IMR 4198. Chronographs at 1365 fps and no smudge stains on the cases after firing. I'm guessing that they're expanding in the chamber just enough to seal everything off. I believe the pressure on this load is around 17,000 psi.
Nice gentle load, my 115 lb. wife will even shoot them.
 
Stocker said---I do think your RP brass is out of spec either as made or????

Look, I know a bit about brass and reloading. Don't make out like I buggered the brass cases.
These are new, never primed or loaded Remington 45-70 cases I am measuring and talking about.
 
Boo, I noticed that the Starline brass was much heavier than the Remington brass. I was keeping them seperate and it will work perfect to keep them for the heavier loads and use the Remington with pistol primers for light loads.
 
sniper58 said:
The best load that I've found with 405 grain cast bullets is 32 grains of IMR 4198. Chronographs at 1365 fps and no smudge stains on the cases after firing. I'm guessing that they're expanding in the chamber just enough to seal everything off. I believe the pressure on this load is around 17,000 psi.
Nice gentle load, my 115 lb. wife will even shoot them.
Click to expand...

Your load is very close to my load mentioned, 33 of 4198 with the 420 bullet. I too, found it to be mild, but excellent for accuracy.
When you get over 400 grains, 15 grains difference in bullet weight is really a nothing.
 
sniper58 said:
The best load that I've found with 405 grain cast bullets is 32 grains of IMR 4198. Chronographs at 1365 fps and no smudge stains on the cases after firing. I'm guessing that they're expanding in the chamber just enough to seal everything off. I believe the pressure on this load is around 17,000 psi.
Click to expand...

Yes, but you are shooting yours in the "fraternal twins" :yingyang: #1s with tight chambers. My Marlin - and other lever actions I suppose -have a little more generous chamber dimensions.


sniper58 said:
Nice gentle load, my 115 lb. wife will even shoot them.
Click to expand...

Never - never - underestimate the strength of a small woman. ;)
 
H4831; Sorry , missed the line in the first post that referred to measuring new brass and thought this was previously used brass you had found the problem in. I was actually thinking in terms of improper heat treatment rather than anything you had done.
 
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