Ruger NMB 45 Colt

[inspector_17]

I have loaded 230 grn rn cast and 250 grn xtp in my ruger with no problem. Got myself a 300 grn rf gc mold to try out. Have cast and gc'd and loaded a few rounds but, Problem I have is the cartridge will not load into the cylinder. I am using H110 with a COL of 1.650 as recommended by the load table for 300 grn jacketed. (don't have aa #9) Do I need to get the cylinder reamed for the cartridge to fit? Or can I safely reduce the COL?

[Love Life]

Bullet may be to fat for the throats at the ogive. Either size smaller diameter, ream the cylinders, or seat deeper (while reducing load proportionally).

[Outpost75]

Correct solution for this common problem is a Redding Profile Crimp die.

This will gently size the oversized bullet by compression inside the case, and bring the loaded rounds to within SAAMI Max. Cartridge dimensions.

https://www.midwayusa.com/product/292753/redding-profile-crimp-die

[DougGuy]

The correct solution is open the throats and forget about "compressing" the boolit in the case. The sides of the boolit are what is too big for the throats, before you even get to the case mouth. This is typical of Ruger SA cylinders and is a one-time fix, size your boolits to .452" size the throats to .4525" and it will all work fine.

Never seat lower as a workaround for undersize throats, unless you have published data for the shorter COA, you could end up with dangerous pressures.

Also, is your NMB a TWO or THREE digit prefix in the serial number? The TWO digit prefix is the larger frame gun and can safely take the Ruger Only loads to 30,000psi. The THREE digit prefix is only rated to 23,000psi, same as 45 ACP+P pressure.

[Outpost75]

If only interference is at the throats, DougGuy is spot-on. BUT if his oversized bullets are bulging the case body so that they don't chamber, it is more than just a throat problem, but inadequate release clearance, which is what I was getting at. Just to clarify.

[Larry Gibson]

If only interference is at the throats, DougGuy is spot-on. BUT if his oversized bullets are bulging the case body so that they don't chamber, it is more than just a throat problem, but inadequate release clearance, which is what I was getting at. Just to clarify.

I concur, OP does not state what, if any, he has sized the bullets to. I suspect the size of the bullet to be the problem.

[str8wal]

300 grn rf gc

What diameter are the bullets sized to?

[inspector_17]

Sorry it took me awhile to get back. I size to 452. Would sizing to 451 be better? I do get a small but noticeable bulge in the case where the gc would be. Still shows up when attempting pcing. And it is a three digit prefix in the sn.

[Groo]

Groo here
Your gun may have tight chambers [good]
Get a Lee factory crimp die.
They have a carbide sizer thet sizes boolet and case to normal size for factory ammo.
Had a 10mm and a .454 that would run factory but no reloads till I used the Lee Die

[DougGuy]

Ok.. THREE digit prefix, safely rated to 45 ACP+P 23,000psi pressures. This 300gr boolit goes 320gr lubed and checked here. I feel you might be hard pressed to get enough velocity before pressure becomes an issue. Those need spin to stabilize, and they may not group well at 850fps, which would be my guess at pretty close to max within the pressure ceiling.

Your medium framed gun is not rated for the Ruger Only 30,000psi loads.

Personally I think you would be much better served with less boolit weight, ideally a 250-270gr boolit at roughly 1150fps might be max for this boolit weight, and if you don't need to push it that hard, that same boolit at 900fps is NO slouch by any sense of the word.


I am using H110 with a COL of 1.650 as recommended by the load table for 300 grn jacketed.

How much H110 are you using?

Also if you are extrapolating data for a 300gr jacketed bullet, I would figure out how deep in the case the bottom of the bullet is sitting, then compare the lengths of each projectile from crimp groove (or cannelure) to the base of the bullet, and make sure they are the same. If they are not, you may be seating the longer 300gr cast boolit deeper in the case, which would significantly raise pressures.

[inspector_17]

Have a Lee FCD already mounted on the turret. Don't want to get the boolet too tightly crimped. So would sizing the boolet to 451 be better? I have loaded 22gr of H110.