Hi - I am just starting handloading and it doesn't seem anyone is talking about the .375 Win. Does anyone have any good loads for this gun. I want to try the Sierra, Barnes, and Beartooth bullets. I will be hunting all Alaskan game (except the biggest bears). Thanks

Welcome to the board!

In working extensively with the .375 Winchester cartridge in my Marlin 375's, I've found that the hard cast, gas checked bullets will beat jacketed for velocity every time... and usually accuracy as well!   The alloy bullet has a lower friction coefficient and a better sectional density thus making a more efficient round when loaded with the gas-checked alloy bullets.

My favorite powders for the .375 Winchester are AA # 1680, RL-7 and surplus WC680.   These powders when coupled with the Beartooth .377"-250g LFNGC bullets give some very surprising performance!

Another plus for your rifle, if you are seeking top performance and saving nickels at the same time, try either cutting down some .38-55 brass, or simply fire-forming (see instructions in tips section "Foolproof Fire-forming") .30-30 brass to .375 Winchester configuration.   You will gain between 5% and 8% case capacity over standard .375 Winchester brass, and beat the ũ.00 per piece of brass prices as well!   Case life of fire-formed .30-30 in my .375's has been outstanding!

Hope this helps you out a little bit!

God Bless,

Marshall

You mention having more case capacity from .30-30 fire formed to .375 ... isn't that only possible by having thinner walls, thus sacrificing case strenghth?

You are right! *The case walls on either the .38-55 or .30-30 are thinner, hence the increased case capacity! *However, there isn't the slightest hazard using this brass in your .375 Winchester. * Keep in mind that the .375 Winchester is a straight walled case, and most of it's stress during the firing cycle is outward, against the case walls... not back against the bolt face! *(P.O. Ackley did exhaustive studies on this phenomonon and conclusively proved the point) *Where you might get into trouble with the thinner case is if there was a significant amount of back-thrust against the breech-bolt, and then the thinner web of the case head could possibly cause a rupture if there was enough rearward movement of the case from perhaps excessive head-space.  However since this is a straight-walled case, not a tapered bottle-neck design, we don't have that back-thrust against the bolt-face.   Consequently the forces of physics are working in our favor when utilizing a brass case of thinner construction, especially when we look at the following contributing factors entered into the equation.

I'm not alone in the practice of using this brass, and others such as Paco Kelley will advise the same. *You can get one of two results:

The same velocity load as with standard .375 Win brass, but with lower pressures.

Or, a higher velocity load as compared to standard .375 Win brass, but with equal pressures.

I might also interject that todays brass is far higher quality due to advances in metallurgy than it was in 1894-96 when the .30-30 and .32 Special were conceived, thus necessary brass thickness then and now are somewhat different to contain equal pressures. * All this being said, the .30-30 case of the 1990's will withstand more pressure, more reliably than the same case made even 70 years ago, due to our more refined and perfected metalurgical sciences.

The truth is that the .375 Win Brass case is over-engineered for its intended purpose. * Keep in mind that it was conceived in a litigation oriented product development climate... in other words; * make that sucker lawyer proof! * Forget ballistic engineering and balancing case capacity, necessary strength and cartridge design.... first make it litigatiion proof, then worry about making it shoot!

Well, I better stop before I step up on a real-life soap-box!

Hope this helps!

God Bless,

Marshall

I too have a great interest in the 375 Win.  From reading Paco's writings I decided to try the 38-55 for 375 technique.  To date I've only had the ability to load and shoot about 20 rounds, due to being in the process of relocating, but I would have to say that they hold great promise.  The loads were Hornady 220 gr FP and Re7.  I can't wait to try the BTB 250 bullet but they are on backorder currently (Marshall - I sent email about this a little while ago).  If all goes as planned I will use the resultant loads on elk this fall here in CO.  The terrain in this part of the state is less open than some others.  The Marlin carries so nicely and is a lot of fun to shoot.  I've been surprised so far at the low level of recoil, although I suspect that by the time I'm ready to elk hunt, this rifle will BARK.

I'm glad to see there are others who are interested in this round.  It gets little respect from most writers, with Paco and JTaffin being exceptions.  I was even reading an article lately by JDJones in which he flattly called the 375 Win a loser.  Maybe it's not the ultra hot, wham, blam single shot pistol load that the 375 JDJ (and others) is but who cares?  His wildcats aren't available in the Marlin either...so there!

Happy Trails.

Bart

From the posts on the other pages in this section it looks like you can turn this .375 in to a real performer.  Some of those loads with AA 1680 listed in hear really move. Just the info I was looking for.

Hey Marshall...having read your stuff on fireforming 375 from 30-30 brass I have one question, if you'll answer it.  You referred to using a light load of fast burning powder (or something to that effect).  Can you elaborate on what powder and what charge?  Since I've been piling up a bunch of once fired 30-30 brass lately I'd like to give it a try.

Walk tall and carry a big bore.

Bart

I too read the article by Paco so I tried the 38-55 brass in my Marlin in 375 Win. I have had no problems. I did not trim the brass. I shoot a home cast 250 grain plain base bullet. I was sizing at .375 and was not getting any good groups at all, but got a new sizer .377 and shoot 28.5 grains RL-7 win primed and got an average 1650FPS. There were no signs of any problems but when shot of the bench it lets you know it. I'm going to step this down some. This load shot about 1.5" at 25 yards. I am going to step this load down a little and try 2400. Let you know what I come up with.

Longbow

Longbow,

I think you're on the right track with your load development.   Try going even to a .378" diameter bullet if using plain base bullets... you'll find that it might just tighten those groups a tad more!

Those Marlin .375's thrive on .377" gas checked and .378" plain based bullets with the Micro-Groove rifling.  Fill it up and they shoot!

Let us know what you find!

God Bless,

Marshall

Tried something different last night. 250gr lead sized to .377, win primer, 38-55 cases, 22gr 2400, and my Marlin. 1/2" group at 25 yards and a average of 1760fps. I think I found something. I have to try it at a little farther distance. (this load worked for me use at your own risk)

Selfbow