50 yd 2 foot group with cast bullets.

[DonHowe]

Jeff: While there are exceptions, 91/30s are hardly target rifles. Many have terrible bores from corrosive ammunition and seldom cleaning. My last one had a bore that looked like a sewer pipe. Use the largest bullet that will chamber in your rifle. Measure The I.D. of a fired case in the neck area and start there. I like to use powder coated bullets and would try heavier bullets if it were me. 185 to 220 gr would be my choice. Good luck and welcome to the forum. Gp

A "terrible" bore can shoot pretty well with proper fitting cast bullets carrying lots of lube.

[gwpercle]

In this game ... You have to pay your dues .
If it was easy ... everybody would be doing it .
Fist off get a rifle with a nice barrel ...old military rifles except those the Swiss Army used usually look like sewer pipes ... corrosive primers and lackacleaning .

Shooting lead out of a Rough Mil-Surp barrel is like learning to swim with a concrete block tied around your neck ... it just drags you down .
Gary

[pacomdiver]

a couple of mine slug 314 and 315, i cast a 311365 that i beagled and they drop at .315, i powdercoat them and shoot without sizing in the larger ones, or use it unbeagled (.3105) then powder coated for the 312 and 313 ones

[JWFilips]

You are really doing something wrong!Pound cast your chamber! Speed is not going to help you!

[GhostHawk]

I did not find any accuracy with my Mosin's no matter what powder, load etc until I went to .314 bullets and a .314 sizing die for gas checks.

Eventually I was able to increase the size of a couple of my lee molds and got decent accuracy. Say 50 cent piece at 50 yards.

Cast bullet has to be 2 to 3 thousandths over groove. And if the groove is .313 or .314 your not going to find any joy with .312 bullets.

The other option I discovered making flat nose bullets out of rounds was bumping them up. But that is a whole nother story.

[Bigmancrisler]

You are really doing something wrong!Pound cast your chamber! Speed is not going to help you!

What’s pound cast?


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[truckjohn]

A pound cast is slugging your barrel, except really only the leade. Hammer a soft fishing sinker into the chamber, just barely into the rifling, then knock it back out and mic it with a micrometer.

Lead is soft and mushy... Easy to squish with a mic... Easy to screw it down hard till it clicks, and you've crushed the lead 0.003" or so. Close the jaws till it just stops and read.

[Kosh75287]

Use CERROSAFE and see if you can use enough to get into the throat and first rifling of the barrel. Between now and then, you might consider assembling loads with 16.2 - 17.0/2400/167 gr. Missouri, in 0.2 gr increments, just to be MORE sure that the bullet instability isn't from velocity being in a "marginal zone" for that particular projectile. The slightly increased pressure(s) from elevated powder charge weights may also assist bullet obturation, which may engage the rifling more completely.
I'm not sure if anyone responding to your inquiry has mentioned paper-patching some of your Missouri coated bullets, but it MAY "fill the gap" between your .312" projectiles and your (likely) .314" bore, enough to impart more spin to the projectiles and tighten your groups.
Lastly, and this is NOT an indictment of your bullet casting skills, but have you weighed your cast bullets to determine variability, before loading them? I doubt that this is THE problem, but it may be a contributor to it. I know that, when I cast ANY projectile for the first time, it's almost an unwritten law that the first 2 dozen or so will be all over place in weight, even when I've done my best to get everything right.