30-30 Primers Backing Out

[papajohn428]

Hi Folks!
Got a new gun, a used 30-30 Marlin 336-RC, looks almost unfired, at least on the outside.  But I fired a couple boxes of PMC ammo thru it to get a feel for it, and the fired primers are backed out, probably about .008" past the top of the pocket.  I'm not used to rimmed rounds with shoulders, so help me out here.  If the shell headspaces on the rim, I'm guessing there's a headspace problem with the rifle or it wouldn't do this.  I've seen revolvers do this with primer-only loads, anybody know of a fix for this?  BTW, these weren't wimpy loads, this PMC stuff is pretty stout for a 30-30!  My 35 Remington doesn't leave bruises, thanks to the recoil pad, but this gun doesn't have one, and off the bench, it stings!  :eek:  

Papajohn

[SAWgunner]

That sounds kinda weird.  One would think that is the primer backed out of the primer pocket, then it would flatten like a high pressure load.  Is the face of your bolt scored enough to allow the primer to back out after you fire?


SAW

[Rustyinfla]

You could try sending a few of the fired rounds back to PMC along with the box end flap where the lot number is. They might be able to tell you something from that. Be honest and up front with them, you might even express concern for their company by sending the stuff back to them. A call first would tell you who to send it to. I did this with some Federal stuff years ago when I had a .30-30 Contender.

          Rusty <><

[De41mag]

papajohn;

It's not unusual for 30-30 rounds to do that. A lot of fellas on the H&R/NEF forum, have had that happen to them, with the 30-30 barrel.
Also I had that problem with a Ruger Mod. 77 MKII in 7.62X39. Using American made ammo. Sent the rifle back to Ruger but they said it was normal for lower pressure rounds like the 30-30 and the 7.62X39 to  back out slightly.
I've heard that you can make a primer back out in a cartridge by just firing an empty case with just the primer inserted, no bullet or powder.
I would just shoot that Marlin if I was you.
Good Shooting.

Dennis  

[SAWgunner]

I assume the primer was not protruding too far out of the primer pocket.?  I have never heard of this, which is why I am asking.


SAW

[papajohn428]

It did it on all of them, So I'm thinking there is enough room between the bolt face and the chamber opening when the gun is in battery to let it happen.   I know there is a lot of variation in rim thickness from brand to brand, so I guess it's necessary.  I have Collet Dies so case stretching isn't a big concern.  I guess it's just a quirk of the gun and caliber.  As long as it's not dangerous and the rifle shoots okay, I can live with it.  Thanks for the replies!

Papajohn

[New Hampshire]

My friend had a Marlin that did it as well.  As De41Mag said it is not that unusual for such a low pressure round.  You see, what hapens is that the primer backs out at the onset of firing because all the pressure at that moment is focused through the flash hole.  Under normal circumastances the higher pressure rounds will then have the case back down on to the primer, thus no high primers.  But since the pressure curve of the 30-30 is so low, in many guns the case does not have enough "oomph" to get back down around the primer.  At least this is how it was explained to me.  As far as I know or have ever seen there is nothing unsafe about this.
Brian M.

[jerkface11]

I agree with newhampshire the only high primers i've ever had were with low pressure.

[brasskeeper]

Have the rifle checked by a gunsmith

[longwalker]

I have a winchester model 94 in 30-30 it does the same thing and always has. I gunsmith told me it is not uncommon for the low pressure rounds to do so. I shoot 150 grain bullets through it.

longwalker

[45 2.1]

It sounds like the rifle has excessive headspace, have it checked by a gunsmith with the proper gauges.