.375 Ruger Reload Challenge

[jimeast]

I am loading a gas check lead bullet for 375 Ruger. It's the Lyman 375449. I'm using a Lyman suggested load for this cartridge.

The overall length is specified at 3.220 inches. After loading a few and going to the range, I found the bolt would not engage without a lot of pressure, basically banging on it with the palm of my hand. Once a round was engaged, the bolt would not extract, and needed to be fired first.

Later at home, I made a DUMMY round without crimping, so the bullet was fairly loose and when loading, it worked fine. Inspecting the bullet after, the overall length shrunk to 3.14".

After looking at the SAAMI chmber specs, I realized that the small, thin shoulder on the reduced length bullet was 2.78" from the base and the SAAMI chamber spec starts necking down from 3.76 at 2.73" from the base. I can only assume this small shoulder is the culprit and was jamming in the chamber as it necks down.

Questions:

1) It seems the only proper thing to do with this bullet is seat it lower, requiring a change in powder used.
2) It's gas checked and this will cause the bullet to be seated well below the neck.

Does anyone have any additional advice on this? I've been reloading pistol, revolver and straight walled rifle cartridges for several years, but this is my first bottleneck round. Also, to my dismay, there is no .375 Ruger cartridge gauge available like I have for my 45acp.

 

[someguy2800]

The necked down area in front of the case is called the throat. You will need to size the bullets down until they fit in the throat. The throat diameter on most rifles is just a hair bigger than the bore diameter. It may only take sizing down .001 of an inch or two to get them to chamber freely

 

[jimeast]

Thanks, your suggesting I might be able to load much closer to the 3.22 specified OAL for this load, than the 3.14 OAL the bullet was reduced to when chambering without crimping?

 

[edwardware]

Also consider that data for cast bullets is usually limited by the bullet velocity, not chamber pressure. You can verify this if your reference lists pressures, or by comparing cast vs jacket data for the same powder.

All that to say, you probably have a lot of pressure margin in the cast data; if so a COAL change won't increase pressure out of bounds.

 

[someguy2800]

Thanks, your suggesting I might be able to load much closer to the 3.22 specified OAL for this load, than the 3.14 OAL the bullet was reduced to when chambering without crimping?

You mentioned that shank of the bullet started at 2.78" after forcing it in the chamber. According to the saami chamber drawing the throat should extend to 2.925" which is where the lead of the rifling should start, so I believe your bullets are likely sized too large to fit in the throat. I would try sizing them down in .001" increments until they will chamber freely.

 

[GooseGestapo]

I use the Lee 255gr FN in my .375Ruger.
Seating the gas checks below the neck is ok.
I find that any issues are fixed by using a 2gr Dacron fiber filler wad.
This allows the bullet to move foward due to ignition/combustion into the barrel before the lube can be affected. It also keeps the powder off of any exposed lube.
NOE sells a bore-riding nose design but no more than I shoot cast in my .375, I can’t justify the expense.
I wish Hornady hadn’t discontinued the 225gr PtSpt. It with a reduced load of H4895 was like shooting deer with a .308” 150gr PtSpt.
If you can only have one centerfire hunting rifle, the .375Ruger is the one to have.