Re-Barrel: 375 Ruger to 458 Win Mag

[Jimeast]

I picked up a used left hand 375 Ruger Hawkeye African a while back for a pretty decent price. I'm a lefty and prefer to use a left handed bolt action rifle.

I'm considering re-barreling it to a 458 Win Mag. I reload, shoot mostly lead and am finding reload support (bullets, dies, etc...) for the 375 Ruger is not stellar. When studying the SAAMI specs for both cartridges, maximum pressure is similar and overall length and brass dimensions at the base are identical.

Is the any reason this is not a workable change?

 

[rangerbob]

Mechanically, it should work straight away providing you use a riflesmith experienced in rebarreling, chambering, and one that is familiar with left handed actions. A better solution might be a rebore to 458 and retain the original barrel thus needing no stock work or left over parts. I had a 700 Remington rebarreled to 458 using a rebored 375 H&H factory take off barrel. Working with 458 caliber bores, one needs to match the twist to the intended purpose and bullet weight. If I recall correctly, I shot 458 X 2" American reloads in mine with no more than 400 grain bullets with a 1 in 22" twist. I have a Mossberg Patriot in 375 Ruger and have no trouble locating dies, trimming tools, etc. Hornady makes the brass and factory ammo and component bullets, as does Sierra, Nosler, and Speer.
Reloading the 375 Ruger is like loading an oversized 30-06. Bob!! :mrgreen:

 

[Jimeast]

Great idea, I'll contact JES. The muzzle end is .675" diameter and the barrel is hammer forges, so it may not be a candidate for re-boring, but I'll get an opinion from JES.

 

[cas6969]

What's the barrel contour? If you rebore to 458" you may end up with a rifle so light you don't want to shoot it.

 

[JFB]

Was there a 458 offered?

maybe Ruger (or GunParts) would have a replacement barrel, if you wanted to keep the sights

 

[Jimeast]

You are right, A little math and some looking around on several replacement sights confirms confirms this might not be wise. I calculate that the barrel would lose about .4 lb. The 375 barrrel starts out at around 3.6lb, so losing that much weight probably does not make sense.

What's the barrel contour? If you rebore to 458" you may end up with a rifle so light you don't want to shoot it.

 

[RSIno1]

Might not be cost effective. You shoot mostly lead - do you cast? If so your purchase of a mold and dies is a one time deal. If you don't already have a 458 you need to buy brass anyway and without looking the 375 probably uses less powder than the 458.

 

[mlazarus5388]

The weight issue might not be a game stopper. Particularly if you load your own. I,have a 458 that comes in at right around 7 pounds. It's not too bad with factory loads and quite decent with reload. Stock design plays an important role too.

 

[SHOOTER]

If interested I have a gunsmith that does these. Pm me

 

[Jimeast]

Just a follow-up. After looking at the cost for too long, no matter which way I slice it... It seems the most cost effective path for a lefty to get into a 458 Win Mag is via a used Ruger #1. So, that's my updated plan