7.62x54R Overpressure??? - Pistolsmith
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Old 09-23-2007, 07:50 PM   #1
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Join Date: Jul 2003
Location: Wabash IN
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7.62x54R Overpressure???

Hi All,

I sure could use some help here.

I don't know much about overpressure situations. My new-to-me M44 Mosin-Nagant was exhibiting a "sticky bolt" while shooting some Russian surplus ammunition from 1986.

It has no problem shooting heavy ball from Hungary made in 1951. The action is very slick using that stuff and I can reach over and operate the bolt handle with no problem (I'm a lefty). The ammunition is copper washed steel.

The Russian stuff is light ball. It has a laquered case mouth and primer, and the case is not laquered. It is copper washed steel as well.

When I first fired it I could hardly get the bolt open. I then came to the internet forums and found that the Mosin-Nagants have "sticky bolt syndrome." I followed the steps to correct this.

While it helped somewhat, the problem still existed.

I took a closer look at my spent cases. This is typical of what I found on the Russian stuff.


At first I thought these were a couple scratches, perhaps manufacturing defects.


I then noticed that the case is cracked, with light visible through the crack.

The rifle is OK. It's sturdy, if not purdy

Can someone tell me if this is a sure sign of overpressure? I don't know what else to look for; I've never seen an example of a flattened primer.

The bands which go around the cases look to be from some sort of annealing process. Looks like other heat treated metal I've seen.

Also, this ammo blows moisture of some sort back. Is this indicative of anything?

Overall, what exactly am I looking at gents? Over pressure, or is this typical of Russian stuff?

Personally, I think hard extraction + random case ruptures = overpressure.

The case code is "60" at 12:00 and "86" at 6:00 for those who may be wondering. I do not have a lot number.

Any help is appreciated.

Thanks,

Josh <><
 
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Old 09-24-2007, 08:59 AM   #2
 
Join Date: Mar 2007
Posts: 305
You might take a mic to the stuff that is exhibiting overpressure signs and ruptures against the older ammo that is running fine, noting differences in case measurments at the neck, shoulder, ect. Warsaw pack manufactured ammo is, probably, not subject to the same scrutiny as US manufactured ammo, almost certainly not up to SAAMI specs.


Take this advice with a grain of salt, as I will admit I've no expierence with M44's, only telling you the first thing that occured to me when I saw your post.
 
Old 09-24-2007, 10:43 AM   #3
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Thanks All,

So far as I know zinc is not involved. The cases are advertised as copper washed steel with red laquer sealant.

I do not have the pic of the SPAM can it came out of... but I do have some other pics for ya'll:


Head-on primer view, comparison fired and unfired.


I'm attempting to show the primer depth here. I don't know if this is normal.


Case length comparisons.

Is it just me or does the OAL of the Russian stuff look to be shorter than the Hungarian heavy ball? Photos don't do it justice; the unfired Russian case is definitely shorter in length to the shoulder and to the mouth.


Circled is the bulge which will not let me chamber one of these spent shells.

The bulge is present on every fired case I've examined, and is the reason it's not extracting properly. The laquer has very little to do with it and there can't be any cosmoline left in the chamber anyway, after the cleaning I gave it over the course of two days. Remember, this involved a 20 gauge brush and drill as was recommended.

I was told that the burn rate can change over the years. The ammo is moved around and while it may start out as granules or flakes, the continuous movement gradually makes it finer. Does this make sense?

Any more comments? It's only doing this with the Russian light ball.

Thanks,

Josh <><
 
 
Old 09-24-2007, 02:42 PM   #4
 
Join Date: Nov 2001
Posts: 951
Problems?????

Josh, The headspace on that rifle could wrong, the Russians weren't known for buildin' as fine a rifles as the U.S. or the Germans.

If I remember correctly from your earlier posts You are young and need to shoot cheap, Try to find Boxer primed cases, fireform them to Your chamber, buy a cheap Lee tool and load to less than than max charges. You can reload these a lot of times.

And if that fired brass came from one of my rifles, lookin' at the primers, I'd say there are signs of excess pressure.

Bill Caldwell
 
Old 09-24-2007, 06:34 PM   #5
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Location: Wabash IN
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Hi Mr. Caldwell,

I'm not exactly young; I'm 30 in November. But you're right; I did decide to go back to college.

I'm a fairly experienced amateur gunsmith (will be sending off for my license to work on others when time and money permit). I just don't have that much experience with rifles.

I can tell you however that the chamber is fine, as well as the headspacing. When I picked out the rifle from several on the rack I was able to bum some go/no-go gauges and it's in spec.

This ammunition is the only stuff that looks like this, or sticks. Since working on it everything else is very functional.

I've decided to go with my gut and not tempt fate. Those rounds that are left will be going into storage against a day when I may not have any others. This is mostly because I don't have a bullet puller nor am I likely to aquire one anytime soon! :cry:

I am however seriously considering reloading for 9mm and 38 SPL; I may as well do the 7.62x54R as well!

Thank you sir,

Josh <><
 
Old 09-25-2007, 08:04 AM   #6
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Location: Wabash IN
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I had the chamber checked today as some were concerned about a loose chamber. While it is a bit loose, it is in tolerance and should shoot any quality stuff just fine. This Russian stuff is the only crap giving problems because it's short.

Josh <><
 
Old 10-06-2007, 03:15 PM   #7
 
Join Date: Aug 2006
Posts: 5
My M38 has the sticky bolt problems with wolf, havn't shot anything out of it since.

I did scrub the bore since then, I happened upon some Winchester Metric ammo. It's brass cased and boxer primed, so I'm going to shoot this tomarrow and see how the action does. the ammo is 180grn soft point.

If my rifle still has problems, then I'm done with it. If it runs fine I'll do some reloading.
 
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