Mosin-Nagant Overpressure?

[franklin_m]

Just fired my first ever reloads for Mosin-Nagant. 180gr FMJ over 42.5 grains of IMR4895 & CCI 250 primers. Barrel slugs at .313. These bullets were .311. New PPU brass. Books say this should be middle or lower middle.

Do these primers look like theres initial signs of an overpressure?

Thanks
https://uploads.tapatalk-cdn.com/20200124/5604662035b41977c2f81d6faa13bbc0.jpg

[redhawk0]

Not to me. They look to be within the normal range.....when its over pressure the rounded edges, of the primer where it meets brass, will fill in. (have a right angle in some extreme cases)

redhawk

[franklin_m]

Not to me. They look to be within the normal range.....when its over pressure the rounded edges, of the primer where it meets brass, will fill in. (have a right angle in some extreme cases)

redhawk

Thanks. I was worried about that little bit of "cratering" ... most easily seen on the middle one. That rolling up of the metal at the edge of the divot created by the pin.

[LAGS]

That Cratering around the Dent in the primer is from an Oversized hole in the bolt face where the firing pin fits.
It is a common problem or should I say Condition on Mosin Nagants.
I have never had an issue with any of mine that had a Wallered out hole , or an undersized firing pin.

[redhawk0]

Yeah...LAGS is right. I get cratering like this on several of my older firearms. The primer hole gets larger, or sometimes even out of round due to use/age. Some of the older shotguns had primer hole "inserts" that could be replaced (O/U and SxS) Some revolvers too. What you're showing is totally normal and you're good to go.

redhawk

[franklin_m]

Thanks guys. These are literally my 21st, 22nd, and 23rd reloaded shells. The first 20 were in a Remmy 700 .30-06. I'm just trying to be super cautious. Results were decent enough, and better than the MilSurp! See pic:
255302

[Remiel]

If you are interested there is a guy that for a bushing job to mosin bolt heads to fix the cratering issue. His name is Grimstood Desh, I found him in the mosin modders on facebook.and he has a channel under his name on you tube

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[44magLeo]

On mine most anything I throw together for a load shoots better than the surplus stuff. I think the main reason is we are more accurate with the powder. I have torn down some surplus rounds and measured the powder charges. Some vary as much as 1 gr. Keeping the charge within .1 grs has to help.
Might want to try Hornady's bullets. They are .312. They shoot well in mine. They are 150 gr SP's.
I also have some Speer 150 gr hot core at .311 and some Seirra 180 gr GK at .311.
Leo

[Remiel]

Here's a link to his video on a savage bolt bushing job. https://youtu.be/OtPmU7diLME

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[Larry Gibson]

That is a mild pressure load.

I have pressure tested (Oehler M43 PBL with Finn M39) a bit of 7.62x54R, both milsurp and commercial, and found Winchester 180 factory, Norma 150 & 180 factory and most "modern" milsurp will run 43,000 to 52,000 psi. I load 46 gr H4895 (Norma cases w/WLR primers) under the Sierra 180 gr .311 SP and 46.5 gr H4895 under the Sierra 174 gr .311 MK. they rune 46,500 psi and 44,200 psi out of my Finn M39.....[2606 and 2666 fps muzzle velocity].

Your load is fine.

[LAGS]

I did make a firing pin Sleeve Bushing for one of my Rather well Worn bolt heads.
It wasnt much more than a section of Brass Tubing silver soldered into the trued up firing pin hole.
It worked fine , and never came loose.
A friend of a friend is still shooting that rifle as far as I know.

[Mr_Sheesh]

I would REALLY rather see a reasonable amount of reality checking, almost to the point of mild paranoia is fine, in new reloaders - Pretty sure others here feel the same. :)

A low pressure load won't damage your gun - or you - and won't make you a statistic or create any problems, provided you put enough powder in that it's not a dud. Good to see you checking as you learn! :)

[franklin_m]

I would REALLY rather see a reasonable amount of reality checking, almost to the point of mild paranoia is fine, in new reloaders - Pretty sure others here feel the same. :)

A low pressure load won't damage your gun - or you - and won't make you a statistic or create any problems, provided you put enough powder in that it's not a dud. Good to see you checking as you learn! :)

Thanks. I'm naturally very detail and process oriented. Plus I'm not doing huge numbers, so no pressure to "churn and burn" when it comes to reloading. I tend to check, recheck, and check again. The Remington rounds were perfect. Nice primers, didn't get flattened, and clean firing pin marks. So when i saw these at the range yesterday, I thought it wise to get a second, third ... etc. opinion.

[rmcc]

Just an FYI, sometimes you will get primers that back out from TOO low pressure in your load. Coupled with a little extra headspace (even though within normal range) and low pressure, the cartridge case sticks to the chamber walls and is still holding after the pressure threshold within has dropped. The result is a backed out primer and the first thing you think of is HIGH pressure! Another sign is a lot of soot around mouth of case in a low pressure load. OOPs. I digress! Welcome to a lifelong, rewarding pastime!!

rmcc

[swheeler]

franklin_m I think your loads are probably fine and what others have said about the bolt head being wallered out is probably the culprit. I still "read" primers but think in reality it is akin to reading tea leaves;-). I was wondering what the inside neck diameter of one of those cases measured, that would make you a good starting point for cast bullet diameter. You possibly could use one of the Remington cases to measure also but would have to make sure all of the crimp got blown out to full diameter, they usually don't.

[Catch22]

Thanks. I'm naturally very detail and process oriented. Plus I'm not doing huge numbers, so no pressure to "churn and burn" when it comes to reloading. I tend to check, recheck, and check again. The Remington rounds were perfect. Nice primers, didn't get flattened, and clean firing pin marks. So when i saw these at the range yesterday, I thought it wise to get a second, third ... etc. opinion.

I tend to be the same way. Been dealing with that kind of thing as I develop my 45 ACP loads and analyzing what I'm seeing.

The only thing I'd have to add to what others have said is to ask if you've checked your firing pin protrusion. I'm betting it's fine, but some folks don't realize that it can be adjusted on a Mosin and how to check it.

[franklin_m]

Everyone ... thanks for the advice, I'll do all of the above. Actually, there is a bit of smoke coloring around the necks, both on the Remmy and the Mosin. Given that I'm in the middle / low middle range for powder in each of those loads, I'll measure now, then bump them up a bit and measure after that firing. I'm using Lee Hand loader for these two, which neck size only, this will minimize variables some as well.

[Larry Gibson]

franklin m

The lee loader is fine as are your loads. Bumping the load up a bit with 4895 might improve the accuracy. To many who only shoot at short range because of range restrictions (50, 100 or 200 yards) find such loads entirely adequate. I shoot at longer ranges with mine and prefer to develop loads that match and are regulated to the rear sight range settings. For example the 180 gr Sierra SP load mentioned replicates the Finnish "D" load of the '30S which the rear sight on my M39 is regulated to. I use the 174 Sierra MK load in my M91/30 sniper rifle. With the PU scope properly zeroed to it I regularly shoot out to 1000m with it and can consistently hit an "E" target (US military kneeling target).

Were I to hunt with a MN I would use the 180 Sierra SP load or for factory; Winchesters 180 gr SP load which is loaded with a .311 bullet over extruded powder. It runs 2556 fps at 45,900 psi out of my M39. It runs 2615 fps out of the M91/30 sniper and shoots right at moa for accuracy. As your MN appears to be a M44 the Winchester load runs 2415 fps out of my Type 53 (Chicom version of the M44)

BTW; the Hornady 150 gr .312 SPs are excellent and very accurate for duplicating the "L" type ammunition.

And .31 cal cast bullets also shoot very, very well in MNs.

[franklin_m]

Larry,

Thanks so much. Actually I want to hunt with it next season. I think it would be cool to use a vintage rifle to harvest some venison. My biggest challenge is I have more vintage rifles than seasons and tags!

[Adam Helmer]

franklin,

Why are you using CCI 250 (magnum) primers for such a mild load of IMR 4895 powder? Where did you get that data? Your primers look ok to me.

Adam

[GregLaROCHE]

Why not only prime a couple of cases and pop them off to see if they look the same?

[franklin_m]

Why not only prime a couple of cases and pop them off to see if they look the same?

I'll try that too. Getting ready to go on business trip, will have to try when I get home. Great idea though!

[franklin_m]

franklin,

Why are you using CCI 250 (magnum) primers for such a mild load of IMR 4895 powder? Where did you get that data? Your primers look ok to me.

Adam

Rookie mistake on my part. Went to Wally World and bought only large rifle primers they had. I was in another gun store (big reloading supplier) and he said not to worry about it. So I’ll use them up and then probably switch.

Any recommendations? I have Remmy 700 30-06, Lee Enfield, 2 Mosins, and 6.5x55 Swedish Mauser.

Thanks
Frank

[44magLeo]

Have you shot any factory loads in your rifle? If so how do the fired primers look?
If not buy a box and see. It easy to find the steel cased ammo. These will be full power loads. Even these will show you what the fired primers look like.
If they look like yours, then don't worry too much. Load, shoot, enjoy.
On primers, CCI tends to be a bit erratic with QA. the diameter and thickness varies a lot. Some seat fine other too tight, others to loose.
I've been using Winchester LR for my loading. These work well and readily available around here.
Remington or Federal have worked well for me over the years.
If you find you like reloading I'm sure you will get a bench mounted press soon. Working with a bench mounted press is less effort and a lot faster. Which lets you sped a little less time at the loading bench and more time at the shooting bench.
Most die makers make neck size dies. Some work like your Lee loader does. A close fitting body and sizes just the neck. Some use interchangeable bushings that do the actual neck sizing. With this type of die you can get bushings of several sizes to try different neck tensions to see how that effects you loads.
Lee makes collet type neck size die. The collet squeezes the neck around a mandrel. I use these myself with very good results.
Lee doesn't make a 7.62x54R collet die, but they can custom build one. You send them a few fired cases and bullets and they build a die to match your rifle. I plan on doing this myself. I think that if enough people requested them they may do a production run on them.
A standard set of dies work well. Most get good results from them.
On some cartridges Lee makes dies sets that have both the full length and neck size dies as well as the factory crimp die. This gives the option to size either way.
Even if you just neck size eventually the cases will get expanded enough to be stiff to chamber. Then you just FL size then go back to the neck size.
Leo

[smithnframe]

Did you check the headspace?

[roverboy]

Did you check the headspace?

I was gonna ask the same question.

[franklin_m]

I bought it back in 1994 and have shot it off and on with MilSurp. Never had it head space checked, but it is a good idea. Will do that when I get back from this trip. Cheap insurance if nothing else.

[44magLeo]

Buying head space gauges is one way to do it, scotch tape is another.
With a sized case put one layer on the head of the case. Put case in chamber and slowly close bolt. It may want to stop as you start to move the bolt handle down. If it closes without any resistance add another layer of tape. Repeat till you get to a point the bolt handle wont quite close without a bit of resistance.
Now measure the amount of tape you have on the case. If you measure .008 then you have .008 headspace. If it measures .014 your about maxed out. This should be done with a new case. A fired case can be used but it may not be as accurate.
A case on the first time it is fired fire forms to your chamber. It now is a perfect fit in your rifle. If you neck size this case and load it will have near perfect headspace.
If you full length size then you could add headspace. Proper die adjustment can prevent this. When adjusting a FL die thread it in to about 1/4 from the shell holder. Lube a case. Smoke the neck. Size this case. As you size the case the smoke gets pushed down the neck. Try in rifle It should chamber ok. Turn die in 1/8 turn size, try in gun. repeat. As you screw the die in it sizes more of the case. as the sides of the case get squeezed the shoulder gets pushed forward. At some point the case may hard to chamber. This means the case length from head to shoulder is longer than the bolt head to shoulder in the chamber. This is fine at this point. Now screw the die in in 1/16 turns Repeat till the bolt just closes with no to very little resistance. L:ock the die in this position.
Size another case at this adjustment It should chamber with the same feel as the previous case. If not a bit of adjustment may be needed.
This is a point were the headspace is minimal.
With a rimmed case the head space is measured by the rim. The rim is stopped by a shoulder in the chamber and headspace is the distance between the bolt head and the head of the case. This is fine but can be a bit loose. Sizing the way described the case will now headspace will now be from the shoulder of the case to the bolt head. This method removes almost all the headspace.
Leo