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Hello all. I am running into a new to me problem with a Finnish M39

Here are the pertinent details:

Mosin Nagant Model 39
Bore Slugs to 0.313
Bullets: Hornady 174 GN RN Diameter 0.312
Brass: Graf and Sons
Powder, Reloader 15 46.6 Gn (Box max per Hornaday)
Book Velocity 2600 fps
Measured Velocity 2200-2300 fps average

All cartridges come out of chamber with powder residue and there is powder residue on bolt.

Also there is a bad smell after firing (like sulphur)

It seems to be that pressures must be low and erratic (hence low and variable velocity). Since the brass is coming out dirty and I have that smell issue, it seems like the cases are not expanding to the case walls in firing to properly seal the breech.

I think the throat (at least) is toast.

Any different ideas or confirmation of my theory?

Thanks

That sounds logical to me. Sounds like a perfect candidate for a rebore to some wildcat!

That is a wonderfuly optimitic attitude to a shot out barrel. Only a true Rifle Loonie would come up with that. I have so much to learn

Thanks

BB

Bolivar-

Does good factory ammo like Norma or Winchester produce the same symptoms of sooting? When similar problems have shown up in shooting some of my mil-surps, I'll try some factory rounds. This helps in finding out whether the difficulties might be associated with the rifle or with reloading recipes or techniques.

--Bob

I agree with Mule Deer. I think your rifle is Finnish :>)

Bob33

Ouch! That was horrible.

You may be able to switch to cast lead bullets and still have a perfectly shootable rifle, but at lower speeds.

Every Finn I have ever checked was right on the money at .310, and I've heard the same report from others.

What primer did you use? Is it possible you used pistol instead of rifle primers? My VKT M39 slugs .310. I haven't shot a lot of handloads in it, but I've had no problem like you describe. Is it possible the primer or powder got contaminated with oil or solvent?

Do you mean that a slug pushed all the way through the barrel comes out at .313 or that the throat slugs at .313? I agree with Denton, try some oversize cast bullets. A Lyman 314299 designed for the 303 British and cast as large as you can get to chamber may be just the ticket. Starting it over 20 or so grains of IMR SR4759 (check a manual to be sure)may get you around 1700-1800 fps and a shootable gun again.

JSH

Slug was pushed all the way through the bore (00 Buck)

A couple of outers have suggested the cast route and I thought of it myself. I haven't gone there yet cause it seems complicated (alloys, hardness, temperature, sizing, lubing, gas checks etc). However, there are thousands of shooters out there casting their own and probably not all of them are rocket scientists.

I figure I'll try commercial hunting rounds in it first to make sure it is not something weird with my load and then move forward with casting if that seems to be the next obvious correction. I should be casting my own for my 45 ACP and 38 Special anyway.

Can anybody recommend a "Casting Lead Bullets for Dummies" book for me. Maybe Lyman?

"Sometimes" this may happen when using a to slow of burning powder; because the case does not expand fast enough.

Sooooooooo you could try a faster burning powder and observe the results.

Lyman Cast bullet handbook is a good start, and joining up over at www.castboolits.gunloads.com is a great place for advice and equipment.

Midway has a sale on Bulgarian made ammo, a case of 880 for $200...jim

http://www.midwayusa.com/viewproduc...=bigimage&utm_medium=special30620093

Also there are a flock of wildcats in Finland based on the 7.62 X54R, or Soviet .30-'06 as it was known to some. Gun Digest had an article on them some years back...jim

Okay, got to the range on Friday

10 rounds prevously fired brass. 46.6 Gn RL15 174 Gn Horn RN WLR primers
Average velocity 2365 fps
Extreme spread 267 fps
Stdev 96.41

Dirty brass, three rounds came out with dented shoulders (perhaps unburned powder granual shuck in chamber or gas leak)

8 rounds unfired fired brass. 46.6 Gn RL15 174 Gn Horn RN WLR primers
Average velocity 2305 fps
Extreme spread 302 fps
Stdev 101.6

All brass came out dirty. One round squib. Pulled out and bullet stuck in rifling, really stuck. Most powder not burned and clumpy. Some discoloured almost like I had mixed powders in that case?

18 rounds Privi Partizan 150 Gn factory Loads
Average velocity 2673 fps
Extreme spread 88fps
Stdev 23.2

So obviously, based on the uniformity of the factory loads, there is not a problem with the rifle. It's my handloads.

Is it possible that RL15 is too fast a powder, resulting in low maximum charges and low densities? Is my reasoning backward on this?

My available load data for the cartridge is sparse to say the least. I probably need to by the Sierra and Lee Manuals (they were on my Christmas list by Santa filled my stocking with other generous presents, including a package from Eileen Clarke JB)

I have noted that H380, IMR 4350, Win 760 and VIHT N-160 shows max charges between 52.4 and 53.9. This should fill the case more and provide greater load densities. If only I had any on hand. The closest I have is H 4350 but I can't seem to find any load data for this powder and cartridge. Time to do another net search I guess.

(update - Hogdon's 2009 manual has been reviewed and load information found)

Of interest, dropping down to load data for 150 GN, RL 15 has close to the largest max charge (all according to Hornady 5th Edition) at 48.2 Gn. They only show Win 760 higher at 55.2 Gn. I believe this supports my theory that RL15 maybe faster than optimal for 174 Gn bullets in this case. Strange cause it is my go to load for my 303 with the same bullet weight and a 44 Gn powder charge (proven safe my rifle, but slightly over published max)

Of course, I may have bad batch of powder which is bad news for my 243 and 303 for which I have put together 50 rounds each for upcoming competitions. At least my 243 is a known tack driver so if the powder is wonky it should show up pretty clearly on paper. I'll figure that out next weekend when I can get back to the range.

Can anyone support or debunk my theory on RL 15 proving to be too fast a powder for this cartridge and bullet weight?

Bolivar-

Your results with the factory ammo will be helpful in diagnosing the problems with your reloads.

A couple of my old rifles have caused difficulties that closely resemble yours; I wondered in those cases whether something was messing with the orderly fabric of the universe.

The frustrating difficulties of working with reloads in mil-surp rifles that take cartridges like the 7.62x53R (=7.62x54R) is the lack of standardization. In this cartridge, interior barrel dimensions can vary widely, both land and groove diameters. As a result, interpreting and applying the recipes in loading manuals is difficult. If one adds in the variables introduced by barrel wear and erosion, particularly in the throat, the difficulties in arriving at an acceptable load are greatly multiplied.

For example, the 2009 Hodgdon manual shows all their loads with .308 bullets. The manual does not disclose the characteristics of their test barrel, but it undoubtedly differs substantially from your rifle's barrel. So, what manuals show as starting and max loads may not apply to your rifle.

RL15 should be an acceptable powder in the 7.62 with your 174-grain bullets. It may not be a case-filling load, but that's OK. Many perfectly acceptable loads have been used for decades with similar powders in cases with similar capacity - for example, 4064 in the 30-06.

Your reported observations indicate that you are not getting a sufficiently high initial pressure before the bullet gets very far out of the case. Your squib load demonstrates this, assuming you had your stated amount of powder in the case. (Your report of "discolored" granules is typical. I'm guessing that they were yellowish. I still haven't figured out what happens to the graphite coating in such instances.)

Because you know that the factory loads produce acceptable results, the next step in seeking a good reload is to find whether it's your reloading techniques or the amount of powder that is causing the problem.

You might try the following, assuming your factory case is boxer primed. (See NOTE below.)

Resize a case from the factory loads you successfully fired, using your customary methods. Check case length, and trim if needed. (It shouldn't require trimming, but check anyway.) Prime the case as usual. Then pull the bullet from one of the unfired factory loads, and finish loading your resized-primed case using the powder and bullet from that unfired load. Be sure that the overall case length is the same as for the factory load. Repeat a couple of times, so you have at least three reloads.

Try firing these reloads, along with a couple of factory loads just to check on things. If the reloads using the factory bullets and powder charges still show sooting, then you know that the problem is likely one associated with your reloading techniques, and not the amount of powder.

If sooting does still occur, the solution may involve increasing case neck tension on the bullet, or crimping the bullet in the case.

If sooting does not occur, then the problem is likely that your charge weights of RL15 are low, and need to be increased. Carefully!

Are you full-length sizing your reloads? Just as with the .303Br, this can cause problems with the 7.62 and result in overworking the brass to produce early case-head separations.

Good luck. Keep posting on your progress with this puzzle.

--Bob

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NOTE about above: Realize that this is internet advice, and may result in complete and total disaster, including destruction of property, and serious personal injury or death to yourself and bystanders. Be sure your property, liability, and life insurance policies are all paid up, and that you have performed appropriate religious rites, if applicable, before attempting the above. Also check this advice with somebody else, so you or your heirs can sue them, instead of me. Try pulling the trigger remotely, with yourself and all nearby living sentient beings hiding safely behind a shrapnel-proof barricade.)

Bullshooter

I wish you had given me your idea about reloading pulled bullets before I used up all my factory ammo

I had not thought of case neck tension. That might be worth a try at some point. I believe most factory ammo is crimped and all milsurp is too.

I am going to try some slower poweder (H4350) and carefully work toward max book charge to see if I get rid of the case sooting.

I am also considering carefully increasing the charge of RL15 and seeing if that shows some improvement.

What seems really odd is that I have never experienced the case sooting or denting before. Normally starting at 10% below max shows nothing except lower than max velocities and mediocure accuracy

Seems to me like too light a charge and/or of too slow a powder, and/or not enough neck grab to get things going in the boiler room. I did some experimentation with an SKS and pistol 32 cal 90s and 100s. I had used 322 speed powder with 123s, but when I stuffed the case with 322 and tried that, I had a barrelful of powder granules and smoky cases. Went to 4198, problem solved.
Your variations indicate real inconsistent initialization, which is what happens when a powder isn't working up against itself.

I have noticed neck tension mentioned a couple of times here. The Graff brass has very thin neck walls. This has concerned me enough to add a bit of Lee crimp to it for a bit of pull on the bullet. My finn has .309 groove in it and so I use a neck die for a .308 bullet and it still is very light on the neck tension. This does work fine but I am not expecting long life for this brass.

Crimping eh?

I have always stayed away from it personally. Seems like another wonky variable. I might as well give it a try though to see if I can get a little more POP to get the case to seal against the chamber.

I think I'll try that along with the other test loads for next weekend. I have already loaded a few rounds with PP brass to see if that makes a difference as well as some increasing charge rounds using the Graf's brass. Maybe a little bit of neck tension will help.

An problems with simply crimping with the RCBS seating die being set to seat and crimp in one step? How about using bullets with not crimping grove.

I am only looking for tenson in crease, not a role crimp so I assume that this can be accomplished without wrecking the bullets if adjustments are made carefully?

You could very carefully try the roll crimp with your bullet seating die. I would do it as a seperate operation though with the seating stem backed off after seating depth is done. If you gain this way, it might be worthwhile to purchase the Lee crimp tool as it seems to work better for bullets less cannelure.