Which bolt action for a custom 375 Winchester?

[rich5674]

I would like a bolt action rifle in this caliber but not a lever action. Which action could handle the rim size (same as a 30-30) and the pressure (50,000psi) ?

[GatCat]

It seems to me that if you could find a used remington 788 in .30-30 it would be an easy change-over. You might want to test some .375 rounds in the .30-30 magazine first, to make sure that there is no "glitch". ALso, the magazine may not be long enough for you to use pointed bullets.

[rich5674]

I had 2 788s, good shooters, crappy magazines. The 30-30s comand a collectors price now.

[Lone Star]

A Lee Enfield Mk4 No.1 SMLE might be a possibility.  The rims are different - 0.540" vs 0.506" - but the extractor still might work okay or be able to be modified.  Thewse are now commonly converted to .45-70.

Pressure-wise the .30-30 has just 85% of the .303's internal case area, so at 50,000 psi the bolt thrust would be near the same as 43,000 psi in the .303.  It should be safe at least.  SMLEs can still be found pretty cheap.   A copy of the Jungle carbine would make a neat rifle in .375 WCF.

[PaulS]

The SAAMI pressure for the 375 is 52000cup and the 303 British is 45000cup. That's a 16% jump in pressure. A proof round is only 15% higher than the SAAMI standard pressure. There are many rifles that will handle the pressure but magazine design may be your limiting factor. Rimmed cartridges have a history of feeding problems. My advice would be to sit down with a gunsmith and see what comes from that. Even if he tells you it can't be done doesn't mean any more than it might be expensive and he wouldn't want to put his name on it for reliability reasons.

[Lone Star]

The SAAMI pressure for the 375 is 52000cup and the 303 British is 45000cup. That's a 16% jump in pressure. A proof round is only 15% higher than the SAAMI standard pressure...

Yes, but chamber pressure alone is not what determines the safe limit of a bolt rifle...or most firearms for that matter.  It is not the barrels which fail, but the receivers.  The smaller inside area of the .375 over the .303 (ca. 15% less) means that the same chamber pressure imparts less force to the action.  

This is the exact same reason that the T/C Contender can safely fire the .223 (52,000 cup) but is not safe for the .308 (52,000 cup).  The larger diameter of the .308 case puts much more stress on the action even at the same chamber pressure.  In the case of the .375 vs the .303, the higher chamber pressure of the .375 is offset by its smaller inside case diameter.  The force difference is a wash, and it is in theory a safe conversion.  Heck, the Ishapore Armory chambered SMLEs in 7.62 NATO....  :eek:

Since the SMLE is designed for rimmed cases it should be easier to convert to the .375 WCF than other bolt rifles.  No one said it has to be a simple, practical conversion.... :wink:

[PaulS]

loneStar,

I know all about complex and impractical conversions. I went through the process of converting an SKS to a "straight pull" bolt action in 357 Maximum after no gunsmiths would touch it. It works but I can't say its practical and it sure wasn't easy.
You can usually get good advice from smiths even if they won't touch the work - That is why I recommend talking to a smith first. I don't think that pressure or thrust is a problem with the gun / ammo in this consideration either but caution is always my first consideration when I put my face next to something that has potential to change my potential for life.

Paul

[rich5674]

That funky reciever makes putting a scope on  a challenge and how much does one of these weight? I'd like to make the "woods rifle" at or under 7 lbs.