Spent casing indicating a problem?

ruger338 · Jan 8, 2013

I have a Remington Model 700 (was an ADL but now has a detachable magazine) in .300 RUM
I noticed first that the primer shows a much deeper hit from the firing pin than I have ever seen with my other rifles or pistols. It actually has a raised lip around the dimple that is fairly substantial.
In addition at the very end of the neck it has a groove after being fired that is about 1/16th of an inch wide going all the way around the casing with the exception of 4 very small interruptions in this groove at North, South, East, West locations when looking straight on.

The rifle shoots great, the rounds cycle through just fine. But I am not sure that I could trim these casings up for reloading.
As an additional note, these are all factory loads so far. I have put less than 40 rounds through it at this point.

Thoughts? Not sure where to begin and I don't yet have a gunsmith here in Eugene. I currently use a man out of Olympia, Wa but that is a long distance to go.

tpigskin · Jan 8, 2013

From what you've described above, the raised lip on your primer is a flow of metal between the firing pin and its hole in the bolt face. This normally indicates excessive pressure and is a warning sign on your load. As to the groove, have you miked the case for OAL? The case may be overlength for your chamber. Do you have pictures you can post?

Mark W. · Jan 9, 2013

Did the rifle originally come as a 300 RUM? or did you have it recut?

I totally agree primer metal flow is almost always due to over pressure only other time I have seen this was with a firing pin hole that was much larger then it should have been in the bolt face and even then it was with a pretty stout load.

The groove could be as suggested a short chamber or long case neck or a problem with the chamber throat.

gophishhhh · Jan 9, 2013

i would expect to see some primer defrormation with the 300RUM unless you are handloading down on the conservative. I am assuming that the factory ammunition is remington ammo. The grrove you are describing is common on the Remington rifle cases. It is created during the manufacturing process and should be nothing to worry about. I beleive you will find that if you slightly kiss the mouth of the with a case trimmer (keeping within OAL specs) that the "interuptions" will clean up pretty easy.

deadshot2 · Jan 9, 2013

Take a look at the edge of the primers on the fired cases. Is there a slight radius still visible? If so, you merely have an oversized firing pin hole. This can be corrected. Best place is Gre-Tan Rifles. Greg Tannel will close and re-drill the hole and the excessive "volcano rim" will go away. For some reason, Remington really is in love with large firing pin holes and to make matters worse, they add a chamfer to the edge of the hole. On my 700 I don't bother with the "crater", I just look for primers that are spread out so much they have no radius remaining. A note however, Winchester Primers will spread far more than others so every load will look like it's overpressure.

Oregonhunter5 · Jan 11, 2013

Gunsmith
Pisco in Coquille
Look them up. Fast!
They know there bubblegum.

DieselScout · Jan 11, 2013

If you cannot find a gunsmith, you could get a Go and No-Go gauge from Pacific Tool and Gauge and make sure they work in your chamber. I had a problem with a .22-250 and it was the first step. Turns out there was dirt in an already tight chamber causing the problem.

millwrt52 · Jan 12, 2013

The crater you see on the primer is the results of Remington beveling the firing pin hole to alleviate primer piercing. They did this from 2008-2010. Their thinking was, the primer would flow some extra metal there and would stop the possibility of blanking the primer, much like a paper hole punch. The marks on your fired necks are more than likely the remains of a factory crimp. Of coarse without pics it's hard to tell.

ruger338 · Jan 13, 2013

thanks to all that responded this rifle was purchased in late 2010 so it does have the large beveled firing pin hole (seems dumb but that's me and lack of a quality product like old days) the rim on the case is a amplified crimp mark from the factory load i looked over many factory rounds loaded and spent and this round really makes that crimp very evident after being fired .

deadshot2 · Jan 14, 2013

ruger338 said:
it does have the large beveled firing pin hole (seems dumb but that's me and lack of a quality product like old days)

Every generation of "Engineers" have their own ideas of how things should be done.

I had a similar discussion with Hornady on a hand priming tool. Their answer was "our engineers, for reasons too many to go into, have decided that that feature is necessary". I removed the feature and instantly the problem with the tool was gone.