Mosin guys - do you neck turn?

[truckjohn]

Hey all you guys out there with Mosin Nagant rifles......

I checked a couple of mine - chamber necks are *Really* tight.... Getting a 0.312" bullet to chamber may be a bit dicey.... Unfortunately, they slug like 0.313".... and would need a 0.314" boolit.....

So... Do you neck turn your brass so you can fit a 0.314" Boolit in there?

Thanks

[Larry Gibson]

truckjohn

As mentioned in your other thread I outside neck turn to true up the necks and then size the bullets so when loaded the case neck is a snug fit in the chamber. I turned some Norma case necks down once so a .314 bullet would work but they were to thin and split on firing.

Larry Gibson

[Smoke-um if you got-um]

Yes. I turn them down to .009 and a .314 cast is an easy slip fit in a fired case. I finger seat and then carefully crimp with a Lee FCD. It's a lot of work to prep the cases but once done the loading goes quickly for the subsequent reloads later. I've also found that S&B brass has undersize primer pockets on some lots and they need to be reamed as well.

Mike

[truckjohn]

Yeah - I ran into the same thing with S&B and their Winchester branded cases as well..... I had me a Big 'Ole Case-Prep-O-Rama this weekend.... The S&B primer pockets were *WAY* smaller than the Winchester.... This seems to be a normal thing with Everything coming out of Winchester in the last few years for me, but I had never fooled with S&B before...

Thanks

[1Shirt]

Haven't yet. Using mostly GRAF brass, and haven't had a need.
1Shirt!:coffee:

[WILCO]

Haven't yet.

Me neither.

[jonk]

I haven't seen a Mosin with a tight chamber yet.

[3006guns]

I ran into what I thought was a tight neck area on my MN (turned out I was measuring it wrong) but one piece of advice I got stuck with me.....

There could be hard carbon built up in the forward portion of the chamber (not uncommon) and will give the same result. To be sure, I soaked mine with Gumout carburetor cleaner and spun a brass bore brush in an electric drill. I actually did get some crud out of there so it's worth looking into!

[Nobade]

I ran into the same thing with mine, tried thinning the cases and they didn't last long. (Grooves measure .314 and a boolit that big is tight in a fired case) So I started loading boolits with COW filler to prevent blowby, and it worked great. Much better accuracy and .312 boolits work fine.

[JIMinPHX]

I have yet to see a tight chamber or neck on a mil surp., so no, I don't neck turn.

[fgd135]

I outside neck turn the cases for my 6.5x54r Soviet Vostok biathlon rifle, after reducing the necks of 7.62x54r brass to 7mm and then to 6.5mm. Otherwise the necks would be too thick to chamber with a 6.5 bullet. Waaaay too thick.

I've never turned the necks on 7.62x54r brass, never have had any reason? Not sure accuracy would improve with an old service rifle, and the bullets seem to chamber without issue. Maybe if I owned a target rifle in that caliber I would try to prep the cases up a bit better.

It's interesting to me that some of the older reloading manuals note that MN chambers can sometimes be too tight to shoot bullets large enough to fit the widely varying bore diameters encountered. I have only encountered chambering and seating issues when I've tried to chamber Soviet surplus ball ammo in Finnish MN rifles that were made with .308 bores and snug chambers, such as the early date M27 and M28 infantry rifles. The surplus rounds (steel cased .311 fmj ball) would not even chamber in them.

[truckjohn]

It's a real phenomenon with Mosins...... Never seen it with any other Mil rifle I own... but I have seen it on several Mosins... Most of those other old warhorses have Roomy chambers.... Enfields seem to be a perfect example of that..... especially the mid-war WWI vintage ones.

I have no earthly idea why they would have made guns with such a perfectly tight chamber - on such a loose bore..... It seems like it would only lead to chambering problems in the heat of battle....

Anyway, I shot some jacketed reloads today - my neck turned brass expanded a bit and it will take an 0.314" sized slug almost perfectly.....

I need a scope on this thing.....

Thanks

[wallenba]

I size and shoot a .315 in my M38. No chambering or extraction issues. Chamber neck seems generous. Winchester brass.

[rststeve]

My mn chamber is like a wash tube lots of room left over. I use graf cases with no issues

[Frank46]

Years back when boxer brass was hard to get I bought 300 of the hansen privi partizan 7.62x54r cartridges. This was before I even had something to shoot them in. I did a swap with a friend who had the nicest Finn model 27 you have ever seen.
Slugged the beautiful barrel and found it was .3115 ok. Then had a .312 lyman sizing die that I chucked in the lathe. Reamed and honed to .3135 or .002 over bore diameter. Rifle shot really great. I am using lyman's 314299 which I bought when they first came out. .314 on the body and .303 on the nose. Later I learned that when the neck as it came out of the chamber would accept the .3135 bullet diameter
without neck sizing and still get great groups. I also made a shorty neck die out of leaded screw stock. Drilled, reamed and honed to just slightly size the neck. Use the lyman M die to bell the cases, add powder and seat the boolit. I have not had to neck turn any of the 100 cases that reside in their own MTM cartridge box. I still have 200 of the hansen cases and about 300 of the norma when they were sold by federal as their American eagle brand. Frank

[higgins]

Truckjohn - Is your MN barrel of Russian or Finnish manufacture?

[swheeler]

My fired brass measures .315 inside the neck, a 91/30MN

[truckjohn]

The barrel is Russian.

Thanks