gas in face-problem with .308's my mosin 91/30

[Bobby Ironsights]

I tried some .308 bullets-150 grain hornady sp interlock's in my mosin 91/30 this afternoon and I had gas blowback in my face. I could feel it, every fifth round or so, six or seven times in all.

I was using the 2.5cc lee dipper full of Varget. I use volume rather than mass, as I cannot really afford an accurate scale at this time.

I looked at the brass, and sure enough, the black soot coated the outside well past the shoulder on almost every case.

For some reason, (low peak pressure due to gas blowby I'm guessing), the brass failed to expand enough to completely obdurate the chamber.

It was unnerving and uncomfortable, and I did not like it.

I had loaded up both these, and some .312 diameter 303 hornady 174 grain round nose interlock and I did not have this problem whatsoever. I did have a little bit of soot creep, but no where near as much as with the little .308 pills.

I think it's simply a matter of generous chamber dimensions, and very slightly undersized bullets.

P.S. I had the 308's recommended by the old guy manning the counter at my local gunshop, and I guess I should know better than to let the idle chatter of an old windbag be a substitute for research on my part.

 

[SKScanuck]

Go here

http://*space*7.62x54r.net/

and follow the tutorial on bore slugging. Fish weights worked fine for me.

You will need a micrometer to measure the slug. Your bore/chamber is generous. I've seen significant variances in my mosins.

You'll have to remove *space* from the link above, we are not allowed to hotlink to non-sponsor sites.

Cheers

 

[stormbringer]

SKS you should read the turorial on hotlinking.

That site is perfectly fine.

http://7.62x54r.net/

 

[tiriaq]

There is obviously not enough pressure being produced to cause the case to expand sufficiently to seal the breech. Get a scale. Lee ones are very inexpensive. You will be able to increase your charges in a controlled manner, if you wish to continue to experiment with .30 bullets.

 

[purple]

You are dealing with a 40-50,000 PSI pressure bloom a few inches in front of your face.FWIW my advice is to stop reloading until you get a scale to weigh your charges.

 

[J.P.]

Ths has nothing to do with the weight of your charges. I didn't check your load, but if you are using the right dipper with LEE data that will not be a problem. Potential problem #1 is 308 bullets in a bore that could be as much as .318 in some russian rifles. The guy at the counter talked you into buying what he had available to sell you. You could slug the bore to find out exactly
what size it is, but i would just buy 311 or 312 bullets. Unless you are actually prepared to make custom sized bullets it really doesn't make a difference if you slug because the resulting knowledge will not help if 312 is the bullet size available. Potential problem #2; Did you use a 308 expander plug or a 311/310 plug in your die? If the mouth was sized with the larger plug you will be getting almost no bullet pull.

 

[Pathfinder]

Stay Safe

Ahhhh good ole mosin's.

I had gas blowback in my face. I could feel it, every fifth round or so, six or seven times in all.

It was unnerving and uncomfortable, and I did not like it. No guff, but you're a braver man than I am if you did it six or seven times.......

I had loaded up both these, and some .312 diameter 303 hornady 174 grain round nose interlock and I did not have this problem whatsoever. I did have a little bit of soot creep, but no where near as much as with the little .308 pills.

You're getting warm...that pipe is generous, like others mentioned slug away..

I think it's simply a matter of generous chamber dimensions, and very slightly undersized bullets.

Correct as JP said some of the bores are up .318.

I guess I should know better than to let the idle chatter of an old windbag be a substitute for research on my part

Correct but now you know, stay safe.

 

[Bobby Ironsights]

OK, Turns out that I was using an insufficient powder charge according to a buddy.

I just used the dipper that was supplied with the lee loader, but a powder that wasn't listed.

My buddy's lyman manual says that the 2.5 cc dipper gives only 34 or so grains and his minimum load shown is 40-something grains of the powder I was using (varget)

P.S. I have shot the rifle with factory ammo, and not had this problem.

 

[louthepou]

I just used the dipper that was supplied with the lee loader, but a powder that wasn't listed.

If you used that quantity of a powder and you didn't get that combination (type of powder / quantity) from a reloading chart, you're lucky the above-described problem is the only problem you got. Get a reloading book. Read it carefully. Go to the Hodgdon web site and print the reloading data. My humble advice. You would have read in the reloading book, or the data sheet, that varget for 150gr bullets in 7.62 X54R requires 47 grains of powder, or use of the 3.4 cc dipper from Lee.

Lou

 

[proonur]

Agree with Lou, and would say that if you have insufficient charge you can sometimes get excessive pressure built up in the barrel and get a hell of a lot more than just "gas in the face". You could end up with a Mosin Nagant pile of kindling and shrapnel in your face.
Absolutely get a manual and a good scale as recommended already.
My friend likes to go the other way and load his stuff "hot" to get more performance. Well, now his brand new Savage predator is in the shop getting fixed because of it.

 

[carbonrod]

Like everyone has said, you need a scale. On the plus side, your dippers can speed the weighing process on the scale.

 

[buffdog]

Light Loads

OK, Turns out that I was using an insufficient powder charge according to a buddy.

I just used the dipper that was supplied with the lee loader, but a powder that wasn't listed.

My buddy's lyman manual says that the 2.5 cc dipper gives only 34 or so grains and his minimum load shown is 40-something grains of the powder I was using (varget)

P.S. I have shot the rifle with factory ammo, and not had this problem.

You have just discovered your problem. The blackening or soot on the outside of the case is also a good clue.

Brass expands to the walls of the chamber to seal the gases. It has to have a minimum pressure to do this. Your loads are under this minimum, and therefore the brass is not expanding enough to seal.

Cartridges also vary in thickness, with the thinner parts being near the neck and the thicker part near the head. This is to help sealing the cartridge case in the chamber when fired.

I would also caution you to learn a lot more about reloading. Learn about pressure signs, switching components, and such. When something "ODD" happens, stop and investigate. Do not keep shooting after an incident.

Above all, the one piece of equipment you MUST have is a scale.
.

 

[Pathfinder]

Good ole dippers....Ive been using them to dump powder onto my scale, Ive been thinking about a thrower / tricker combo to speed things up.

 

[Claven2]

You have two problems:

1) uncontrolled, and probably too light, charges.
2) undersized bullets. The Mosin has, on average a .312" bore - NOT a .308 bore, unless it's a finnish M28/30.

 

[John Sukey]

Solution: buy a Lee Enfield! The gas escape hole is on the SIDE of the reciever.

 

[sunray]

"...Turns out that I was..." Nope. It's the wrong bullet diameter. A Moisin uses a .311" or .312" bullet.
A Lee-Enfield doesn't use .308" bullets either.
The old guy in the shop didn't know what he was talking about. Mind you, if you asked for bullets for a 7.62, that's what he sold you.
In any case, pitch the dippers and buy a scale. The dippers can vary the charge by a full grain. And CC's are not a standard unit of measure for reloading. Why Lee uses it is anybody's guess.
Buy a manual and never substitute powders.

 

[Vieux Schnock]

I had exactly the same problem with my Steyr M95. I had no problem with the surplus loads but it started when I tried reduced H4895 loads. Since the gas hole is on the top of the breech, I could feel the blow on my forehead . I was using cast bullets (.329) . I reduced the load and it made it even worse. I went back to the book, picked a full charge load and it worked : no blow, no black ring around the collar.

At least the H4895 is safe for light loads . According to Hogdon, you can use as little as 60% of a regular load. With most powders, reducing too much may create explosive charges.

Besides, Reloading without the proper equipment is playing with fire. Lee has a scale in its catalog that may be a bit slow to use but its precision is quite good. Relying on volume and tables when humidity can vary like it does at summertime in some places is risky. I keep 45% humidity in my reloading room . When my deshumidifier failed 3 weeks ago, it went up to 80% . I'm telling you : having a scale is a must.

 

[goldidig]

I don't understand why using a .308 diameter bullet should do that. .004 thousands of an inch smaller is really nothing drastic. Supposedly makes for inaccurate shooting, but it sure hasn't for me. Like some of the other guys said, it is simply the too low powder charge causing the blowback of gas.
I have been reloading 7.62 X54R for about 20 years now and all I use is .308 diameter bullets for my M44 carbines. They shoot very accurate in those guns of mine too, at least on the 100 yard range. They consisitently group around 2 inches at 100 yards so seeing how most of my Lee Enfields do 3 inch groups I consider that VERY good. Maybe I was lucky and the bores are a bit tighter than normal but I doubt it. I have often wondered how good they'd group with .312 diameter bullets if they shoot like that with .308? Whatever the reason, I have shot many hundreds of rounds with no issues and taken quite a few deer as well over the years with the one gun using my handloads.
If using a simple Lee Handloader kit, the supplied dipper is just fine as long as you STICK to the load data chart they provide. Use the proper bullet weight and powder combination and you will have absolutely no problem.
Al

 

[wesm]

P.S. I had the 308's recommended by the old guy manning the counter at my local gunshop, and I guess I should know better than to let the idle chatter of an old windbag be a substitute for research on my part.

Despite being the "old windbag's" nephew, I'd suggest very strongly watching how you do your reloading. Have a look at some of the pictures and pieces that are around in the shop from others that didn't pay full attention to reloading and ask yourself if you want those pieces in you.

"The old windbag" has likely forgotten more about reloading then you will ever know. Have a chat with some of the regulars there about his knowledge on the subject of guns and reloading. I think you'll find his to be encyclopedic.

Do be careful where you do you research as well. The internet is not the best place for it. Make sure you get the manual, a scale, and the powder they are recommending rather than just winging it. We don't need any accidents with firearms to compound the public relations problems we are already having.

Enjoy your shooting. If you are testing your handloads at the Nolalu range (assuming you have a membership) let us know please. We'll be on the other side of the berm.