Seeking advice on reloading for M91/30

[chaplaincolby]

I've been lurking around for a while and have learned a lot. It's now time to seek a little advice. I have a 1943 Mosin 91/30. I've slugged the bore 3 times and I consistently get a bore diameter of .305 and a grove diameter of .3165. I've only shot factory or surplus ammo with mixed results. All the ammo has had bullets that measured at .311. The gun doesn't really group but has settled out to putting most bullets into a 12 in circle at 100 yards. I want to start reloading for this gun both to save money and to improve the lackluster accuracy. For me acceptable accuracy with this old gun would be a 4 or 5 in group at 100 yds. I think that the large grove size has a lot to do with the poor performance. I have accumulated 60 PPU boxer cases to reload with.

Here are the options I'm considering.

1. Reloading using the Hornady .312 174 grain RN jacketed bullet. Will the extra .001 in diameter help since there will still be .004 gap in the groves? This bullet however has long straight sides that may help stabilize the bullet. Also the price, when I can find them, is almost $40 per hundred. At this price I certainly don't save any money from factory ammo. I haven't found any jacketed bullet that is sized between the .312 and a .323 8mm bullet.

2. Reloading using a cast bullet. I'm considering the lee C312-185-1R mold. But since a cast bullet is supposed to be .001 -.002 larger than the grove It doesn't appear that this mold will be large enough. Will it? I don't want to spend a lot of money for a custom mold and the largest I have found is the NOE .316 But it's cost is more than I'd like to spend for a $150 rifle. Could I cast a .323 bullet and size it down to .318 and be successful? I have not found any sizing dies larger than .314, any options for a .318 die? I measured the ID of a spent steel case (Tula Ammo) and found it to be .3155. Do you think I will even be able to chamber a bullet larger than .316? If not would a cast bullet sized at grove diameter be successful?

3. Regardless of bullet I want to do a reduced load to ease recoil which for me should improve accuracy on the shooters part. I'm considering either a reduced H4895 load or use Trail Boss. What are the advantages of each powder? Can a reduced load be use for both jacketed and cast bullets?

Finally am I expecting too much for this old over-sized bore gun? Any and all thoughts would be appreciated. Thanks.

[durango kid]

Over sized sizing die is the easy part anybody around you with lathe can bore your die turn new pin I do this all the time.

[Green Lizzard]

i have a smle that is the same size and i use the lee 185 .313 as cast but i install the gas check with a 315 sizer that i honed out, not a tack driver but easy 200 yd gong pointy end first on paper and no leading. your throat may not take a bullet that big you will just have to measure and see. this set up beats your 4 moa requirement in this old smle.

[jonk]

Here's what I would do.

De-copper the bore thoroughly. Measure again. Sometimes the copper build up can be bad enough that you actually gain a thousandth or two in the grooves after removing.

Measure the muzzle erosion. You'd want a pin gauge for this. All the advice in the world isn't going to matter if the muzzle measures .320 or something. If it's worn beyond the .3165" bore much, you need it counterbored.

Take a fired case and measure across the inside of the mouth. Hopefully it is larger than .318". If not, you're kind of stuck, and will have to neck ream brass or just accept you'll shoot undersized bullets.

Assuming the case measurement is larger than .318", I would size bullets at .318" given a .3165" bore.

Order a .318" sizing die. Member Buckshot here will do you up one that's really nice at a fair price.

Now for the bullet. A few choices here. Option 1: you might try beagling the mold- which is to say using aluminum tape shims to open it up a bit. Getting 6/1000" is a bit ambitious, but you might get lucky with the Lee 312. Option 2: Order a Lee .324 mold for the 8mm Mauser, and size down to .318. I do this for my Czech-rebarreled Gewehr 88. Not an issue. You might want to lube in a .323" die first then size down in a push through to keep the lube grooves intact.

Modify a die set. What I did was order an 8mm decapping rod from Lee, spin it in my cordless drill with some fine emery paper, measuring frequently with a micrometer, until i had turned it down to the requisite size- in your case, you'd want it around .316-7", so that the bullet has adequate tension. Swap that out for the stock expander rod in the die set. You can do this with other brands of dies, it's just the Lee with the solid one piece unit is easy to work with. That done, hone out your seater die neck to accept a bullet of the desired diameter. I used a chopstick with some emery paper glued on it. Remove the seater ball, and spin the rod in the neck to open it up until your desired bullet will push through with little or no resistance.

Lot of work. But if you really want to shoot cast in it and get accuracy, that's what you'll be looking at.

Assuming you have a .316" bore, measure a fired case and see what

[Larry Gibson]

There are numerous things to do with loads but 1st make sure, as mentioned, the rifle is up to improved accuracy. Clean the bore really well and slug again with 5 slugs as it is easy to damage one and get a false measurement. A .316 groove diameter is not that difficult to load cast for. Also as mentioned check the crown as many MN crowns are really worn. Is your rifle's crown counter bored?

Larry Gibson

[Joe504]

If the mold is a problem, might this be a good candidate for paper patching?

[chaplaincolby]

Here are the answers to some of the questions that have been asked. Thanks for the great input so far.

The gun has been cleaned many times over the last year. About the only cleaning method not used yet is the electric charging rod method. Patches come out black after shooting, running a patch wet with Hoopes #9, and running a bronze brush through the barrel.

I've slugged the bore 3 times and I consistently got a bore diameter of .305 and a grove diameter of .3165.

I measured the ID of a spent steel case (Tula Ammo) and found it to be .3155.

The barrel is not counter bored.

I don't have a pin gauge, but my calipers measure .305 to .318 at the muzzle

Hope this helps

[craig61a]

I have a number of Mosins I load for that range from near spec to .315. I shoot copper and lead out of them depending on the bore diameter. For reloading I use a Lee .303 brit collet neck sizer and a number of different mandrel sizes, depending on the diameter of the bullet I'm using. I also have some .318 copper bullets that size down to .314 and shoot out of a M38 for deer; It's an accurate little rifle with my handloads...

[Outpost75]

You also want to measure the neck diameter of a chamber cast or fired case to ensure that there is safe neck clearance to load a cast bullet as large as. 316". You might try loading a dummy cartridge with a .316 bullet and see if the dummy round will chamber and extract without resistance. If your chamber neck s too tight, you will needcto either outside neck turn or inside neck ream brass to obtain safe clearance. If a sized bulet will not enter a fired case, therein lies a clue!

[Larry Gibson]

Chaplaincolby

Sounds like you've got goo measurements there. One last question; does the rifling (lands) come to the edge of the crown square and sharp?

Larry Gibson

[chaplaincolby]

Larry, the lands are square, but not sharp at the crown. Here are a couple of photos, one of the crown and one with a light in the bore to show the rifling.
8621486215

[Larry Gibson]

That is atypical of many MNs and shows wear from over judicious use of a cleaning rod from the muzzle end. It appears that as little as 1/8" of may clean the crown back up. It is generally the reason for the poor accuracy as you describe. Not hard to do with a hand tool (Brownell's) if you have one and know how to use it. It just might be serviceable with cast as is though if a correctly sized bullet is used.

You can get a NOE mould that casts .316 bullets (316299) or you can use an 8mm bullet sized and lubed at .323-.325 such as the Lyman 323470 and then sized to .316 - .318 in a honed out Lee push through sizer.

Larry Gibson

[chaplaincolby]

Larry, what do you mean by "It appears that as little as 1/8" of may clean the crown back up." Do you mean 1/8" of honing with the brownell tool? Also do you mean that a properly fit cast bullet may make the gun shoot well without any recrowning?

[Larry Gibson]

Larry, what do you mean by "It appears that as little as 1/8" of may clean the crown back up." Do you mean 1/8" of honing with the brownell tool? Also do you mean that a properly fit cast bullet may make the gun shoot well without any recrowning?

The 1/8" refers to removing that much and recrowning. It can be done with the Brownell's facing and recrowning tools. A longer Loverin style cast bullet many times will shoot well in milsurps with worn crowns (taper worn not damaged from dinging etc.) where a cast bullet with a longer bore riding nose won't. Reason is the longer bearing surface and short nose of most Loverin designs. An older Ideal or Lyman 311466 or 311467 that casts "fat" may do very well in your rifle w/o recrowning. The 8mm Loverin design 323470 sized down to .316 - .318 will probably do very well.

Picture shows the 323470's heavier cousin, the 323471, on the left sized down to .314 in one pass. Lubing and GCing before the size down prevents the lube grooves from wiping away and distortion of the bullet.

Larry Gibson

86271

[chaplaincolby]

Thanks for the clarification and explanation Larry

[Ed in North Texas]

You might also look for some of the older Lyman .319 moulds as shown in the Ol' Buffalo tables, they show up occasionally on that auction site. .324s are more common, but the .319s would need little if any sizing.