K31 Report

[jh45gun]

Was out at the gunsmiths today and showed him my muzzle loaders I built. I figured as long as I am out there I will bring along my K31 and have him put his boresigher on the gun to get my scope on paper. He re-adjusted the mount a bit from what I had done and then adjusted the scope.After I left his place I went to a gravel pit I know of and shot my muzzle loader first then the K31. I have to say the K31 was a joy to shoot the muzzle loader needs a pad the recoil from a light muzzle loader with a curved brass butt plate just does not cut it. Anyway it was windy out and I had taped the targets to a board but they would not stick well with the tape used by the time I started shooting the K31 so I just shot at a empty pop bottle ( 20 0z plastic) Never missed once and bounced that bottle and what was left of it for 20 shots at 20 to 30 yards with out touching the adjustments on the scope. Will take it out on Sat to the Range and try for a group. Today was sure fun plinking with it and sure enjoyable to shoot. The load was 16 grains of 2400 with bullets that I cast and lubed with Liquid alox, mould was Ideal 311407 not sized and they were gas checked with the old snap on style of ideal gas checks. Sure wish they still made these for using on unsized bullets. :( Will post a range report after I shoot on Sat unless something comes up that I cannot make it. Jim

[Linstrum]

Hey, there, jh45gun, how ya doin? It sounds like that particular rifle is a really nice one! It also sounds like you had a pretty good time finding that out, too. I’m interested in how it does on some targets that aren’t blowing around in the wind because I am considering getting a K31 myself.

I did a little research on the Schmidt-Rubin and it would appear that the operational dimensions of both the cartridge and rifle are very close to the 7.5 French MAS 36, including the brass dimensions and volume. As such, I’m curious if you have slugged your K31’s bore. If it runs somewhere close to 0.308” groove diameter with a comparatively small land diameter of 0.295” to 0.298”, a barrel length of 22.7” or longer, and a twist of 1 turn in 10.63” or 27 centimeters, then it is indeed pretty close to the 7.5mm French system as used in the MAS 36.

In the event that you don’t have a lot of cast load data for the K31, and if the bore dimensions and rate of twist are indeed the same as the French, then some of the cast load data I have for my French MAS 36 will work for the K31 rifle. Since the cartridge volume and dimensions of the 7.5 French and 7.5 Schmidt-Rubin are fairly close to one another, then the powder charges will probably translate directly if the top end loads are stayed away from.

Good luck!

[jh45gun]

No I did not slug it but according to the guys at the Swiss site the guns run 308 in diameter. I do not know what the twist rate is. Get one now while they are cheap I am glad I did for under a 100 bucks you cannot go wrong and every one on the websites that have all claim they are great shooters. To me they are one of the best deals on the milsurp market today. Jim

[C1PNR]

FWIW, I have one that slugged .295 x .307. Should be a good candidate for the moulds that throw a little undersize.

[jethrow strait]

The grooves on my 1942 vintage K31 run just over .306" and the Frenchy goes .307. I wouldn't give much credence to the talk on such matters in 'collector circles', Swiss or otherwise.

Since this thread is title as a range report on the K31, I'll pass along some of my early condom and surplus results. But first a thank you to SWheeler for hishis 57/WC860/172 condom rec; it worked great for me using the 173 gr. durplus instead of the Hornady(.6" to 1" @50 yds using a Williams FP receiver sight and a standard Win LRP instead of the magnum). Found no gems in the Pierre recs over on the Swiss Rifle Forum, although no really bad loads from his favorite 4064 and 3031 recs., using both 152 and 173 gr. surplus condoms. Seems like the K31 shoots most anything fairly well, but imho it's still worthwhile to tinker a bit. I guess the other standout for me with surplus and condoms el cheapo surplus 7383, of which I have a bunch. Tried 36 to 42 grains, with best accuracy in my rifle coming at 40 grains with the 152/173 grainer surplus bullets going out at a chrony avg. of 2019/1980fps. Hoping that will be a viable load for real boolits in the days ahead.

On to real boolits! Picked up the Harris/Lee 155 grainer mould for the K31, since it is much recommended. Hard to figure out why, since even the bore riding nose drops out of my improved WW alloy at a full .303". Maybe it's the pointy ogive for that virtually throatless rifle???-----------jethrow

[JSH]

Have slugged 3 different K31's. .306+ on 2 of them and 307 on the other one.
Jeff

[Shepherd2]

My K-31s slugged .306, .307 and .307.

[Bob S]

Most of my K31's run pretty close to .308, but I have one that is .3092". It's a 1962 overhaul-rebarrel, and that's the one that shoots jacketed so well, it is my "as-issued" match rifle. It also shoots cast very well when sized appropriately ... my Lyman .310 sizer actually sizes WW bullets to about .3096".

My pre-K31 rifles are the ones that run under .308. A 1901-production 96/11 long rifle slugs prettty close to .306.

Resp'y,
Bob S.

[swheeler]

Jethrow; you are welcome! Glad that my 41 years of reloading with surplus powders could be of help to someone.
Scooter

[Frank46]

where does one purchase 7383 surplus powder. Checked Jeff Bartlett's site and was not listed. Since it seems to be good with cast boolits in the K-31 then it would be good in the 9.3x57 also?. Any help is appreciated. Frank

[Linstrum]

Hi, Frank46: Dan over at Hi-Tech has the IMR7383. Click here on this URL and it will take you there:

http://www.hi-techammo.com/

A word of warning about IMR7383, it is not a universal cast boolit powder, so don't expect it to work wonders in everything. It DOES have a lot of uses, however, and I like it so much that I have bought 70 pounds of it over the last several years. It is a high energy triple base powder (as opposed to a single base or double base powder) and consequently can be extremely cranky with producing unwanted high pressure if you try to push performance by using too much. Use IMR4350 STARTING data but DO NOT use the IMR4350 top end loads or you'll be in trouble! If you load it up to the point where it starts to burn clean and then don't increase your loads beyond that point, you'll do great with it. Also, I don't use it with a magnum primer or compress it. There have been several previous posts on 7383 already, so go back and read those to get up to speed on how it is used. Good luck!

[bart55]

Hi guys , I also have a couple of K31 s and have used the 7383 with only condums my load is around 40 gr with a 152 gr fmj , good accuracy and alot of fun to shoot ,I have also used 5010 with cast rcbs sillouette bullet case full of powder and got great accuracy but alot of unburned granules. Have to watch out and not tip the muzzle up or you will not chamber another round with out cleaning out the unburned granules.

[Linstrum]

Hi, bart55, it says that this is your first post, so welcome aboard the board!

Thanks for mentioning the loads that you use with your K31s. Your 7383 load sounds like a good one for the 152-grain fmjbt. The 5010 load is the first confirmed one I have heard of using that powder in the 7.5 Schmidt-Rubin. Yeah, a barrel full of scorched "mummies" from 5010 is a problem with a lot of other cartridges, too, except for ones like the 6.5 Swede Mauser, .25-06, 7x57 Mauser, etc., with large case capacity and small bore size where the pressure gets up high enough to achieve complete combustion with the great big chunks of IMR5010 "Purina Rifle Chow".

[Frank46]

jh45gun, just for the heck of it I slugged my K31 .295x307. The metal is really nice and so's the bore but the stock looks like someone rode it hard and put it away wet.
Going to get another when I get the bucks. Frank

[Four Fingers of Death]

The load was 16 grains of 2400 with bullets that I cast and lubed with Liquid alox, mould was Ideal 311407 not sized and they were gas checked with the old snap on style of ideal gas checks.

When using gaschecks an liquid alox, do you fit the check before lubing or after?

[jh45gun]

I have only used these older style snap on type so far and put on the checks then lubed them. I ordered a Lee .311 sizer today so I can put on the hornady gas checks when I get some as they do not make these ideal ones anymore. These .311 bullets seem to shoot well in my gun so that works for me as the .311 will be more of a universal size for my 30 calibers. I will be using the same bullet 311407 for my 30/30, a 308, two Mosins and my K31. anyway Lee says to lube the bullets then run through the sizer to crimp on the gas check. Then relube again. Jim

[Luna Park]

I was shooting the other day and I loaded some rounds using 4064 data and 7383 powder. I was shooting my K-31 with 42g of IMR 4895 & 150gBT. That is the load I always shoot with my K-31. When I fired 42g of 7383, I blew a primer out of a case, and I flattened a few others. I will try 39g tomorrow and work up to 41g. I was shooting 40g through my MAS-36 and the 7383 was real nice. I just bought 14lbs of the 7383 and I just thought I would share my first experience with all of you. I have been reading your postings on this powder.
:Fire:

[Maven]

LP, I'd drop back to 35 IMR 7383 with 170gr. - 180gr. CB's for starters and have a chronograph handy. Unfortunately, we know little about 7383 re: how various lots differ in burning rate and pressure curves save what people have posted here and elsewhere.

[Luna Park]

Thanks. I should know better than to use such a load to start. I fired 100 rds today from 38g up to 41.5g. All the loads shot pretty good, with there being some pressure signs at 41.5g. I'm going to back all the way down to 35g like you suggested and see how things go. That powder is such a bargain. There is just so little information on it. Thanks for your help.
:-D