Beware of a good deal on a .375 super mag

[Lee Martin]

[/quote]AT ONE TIME BRASS AS WELL AS AMMUNITION (RARELY) WAS OFFERED. THAT WAS ALONG TIME AGO.
[/quote]

I have a bunch of the old Winchester .375 SuperMag brass. Here's what it looks like (note - the case on the left is a .375 Atomic):





-Lee
www.singleactions.com
"Chasing perfection five shots at a time"

[matt56]

Maybe not a wildcat then just obsolete. I'm getting a rhythm down with the brass. My redding case trimmer is doing a perfect job of the final cleanup too. I put the case up in the trim die, cut it off with a hacksaw, chamfer the inside, force feed it onto the trimmer pilot and run it down. I'm cutting them down to 1.606-1.604". They are coming out great.


Lee how much is a bunch?  Would you part with any?  I would never shoot them, just to collect.    

[matt56]

I would say the 200 grain Sierra JSP is cutting it close for use in a super mag. I tried to do the math before hand but it came out so close I wasn't sure if it would actually fit or not. I'm honestly not sure if I've ever had any rounds jump crimp before but I suppose we'll find out with this one.






I have made 100 brass so far and loaded 20 rounds to test.  Those are stoked with a heavy charge of IMR 4227 and a CCI 200.  OAL is coming out at 2.130".  Lets say 2.075 cylinder length and .058 rim thickness.  That is too close to call.   

[jsh]

Y'all can quit with the 375 SM porn any time ;-).
That what got me here to begin with. Advice from others on building one from a 357 max, I was told to just go with a 41 mag. Now I believe that was a joint effort by folks to keep me from acquiring yet another 357 max to build on, which also got me into the 41 mags (man did I miss out for a long time there).
Now the wheels are turning again on a long put off project...........
Jeff

[matt56]

I came across 150 Hornady 220gr #3705. The noses are actually shorter than the Sierra 200 gr so they'll fit the DW cylinder with a little room to spare. I wish I could find a nice stash of these things.

[jimtx]

I would check GB also Ebay and search different ways I've seen the components show up from time to time for sale.
And of course gun shows, look at the tables closely. When I got my 350 Rem Mag. There was almost nothing around, I found 3 boxes here, 2 there etc and left the show the over 100 rounds of factory Remington loads.
Lol then a resurgence of the round and rifles in it comes along couple years later and new ammo is available after I buy all components.

[matt56]

Actually the 150 I got came from Gunbroker. I have been watching like a hawk. I'm actually thinking of picking up a 375 Winchester 94 rifle too since I'll have all the components. I mean why not, right?

[matt56]

Okay so I finally got a chance to shoot this thing. My first 20 loads were 23 gr IMR 4227 under a 200 gr Sierra JSP. The shots were loud like a maximum but I was surprised how little recoil this gun produces. This load was slightly compressed and I don't see it being max. The cases all extracted easily and they are spotless on the outside.


I shoot on a field pistol range with half scale targets. I was definitely impressed by the knockdown power.


Also I have the ball rolling on getting some extra barrels made for this gun.  I'm going to order a pac-nor 1:14 .375 blank and Eric at EWK is going to cut me 3 barrels from it using my existing barrel for the dimensions.  I'm actually not too far from his shop.  

[bradshaw]

Aug 22, 2018 20:51:48 GMT -5 matt56 said:

Okay so I finally got a chance to shoot this thing. My first 20 loads were 23 gr IMR 4227 under a 200 gr Sierra JSP. The shots were loud like a maximum but I was surprised how little recoil this gun produces. This load was slightly compressed and I don't see it being max. The cases all extracted easily and they are spotless on the outside.


I shoot on a field pistol range with half scale targets. I was definitely impressed by the knockdown power.


Also I have the ball rolling on getting some extra barrels made for this gun.  I'm going to order a pac-nor 1:14 .375 blank and Eric at EWK is going to cut me 3 barrels from it using my existing barrel for the dimensions.  I'm actually not too far from his shop.  

*****

Was mine, I'd order 1:12-twist, and not a lick over .375” on the groove. If the blank allows for a longer barrel, I’d try that, too. Make up a muzzle nut with hex flats for a combination box/open end wrench (which does not contact barrel shroud). Short 11-degree forcing cone, cut on lathe.
David Bradshaw

[matt56]

Let’s say I get a 28” blank that’s enough for three 8” barrels plus 4 extra inches. I could have one of those barrels extended out a little bit and even look for like a 10” shroud. Great idea David, thanks.

Why would you choose a 1:12 twist though? How heavy of bullets could be utilized in a super mag without taking up too much case space?

[bradshaw]

matt56..... since you plan to fit a custom barrel to your DWA .375 Super Mag, which came with 8” barrel, might as well cut one piece of the 28” blank to 12-inches, at least; perhaps 16 or 17" would be better. You’ll have two barrels instead of three, the the longer barrel providing a chance to explore the cartridge.

Barrel #1, 8-3/4"
Muzzle extends 3/4” beyond shroud. A new muzzle nut cut with hexagonal flats, which extends beyond shroud, and is tightened with box wrench.

Barrel #2, 16-inch, finished either of two ways:
a) Threaded for hex-profile muzzle nut, same as 8-3/4”. Barrel turned down (smooth) to root diameter of muzzle threads. Muzzle nut slips over exposed portion of barrel.
b) Barrel turned with a step which eliminates muzzle threads and takes the place of DWA muzzle nut. The stepped-up forward 8-inches of barrel is turned to diameter of DWA muzzle nut, thus slips into countersink at muzzle end of shroud. Cylinder/barrel gap is set by flat washers (cut from shim stock) between BARREL STEP and SHROUD COUNTERSINK.

Such an arrangement provides a revolver and carbine (sans buttstock).
David Bradshaw

[majorKAP]

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[matt56]

Do I have to ask what the story behind that is?