Making of My 375 Wby

RL338

Handloader
Mar 23, 2017
2,139
3,217
Sized the brass last night. Lost one piece in the process. Found out the Hornady press didn’t have what it takes , had to move over to the RCBS. Even with a crap ton of lube it felt like swaging instead of sizing. Peterson brass is some tuff stuff. I’ve made piles of 378 , 416 , and 460 out of basic brass and the Hornady handled it fine.
Bullets I have on hand Speer 270 and 285 grain , Hornady 270 with some old 300 BTSP on its way.
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RL338

Handloader
Mar 23, 2017
2,139
3,217
Late in the day yesterday I loaded 4 that had a crease in the neck with 270gr Speer BTSP. I first ran a couple of patches through the barrel , that puppy is smooth. Loaded those 4 with 83grs of Hybrid 100V and strapped on the Magnetospeed. Granted only 4 shots , I had an ES of 6 with average if 2780. Loaded up 10 more to try after I get my brake. For the heck of it I ran those 10 on my Sinclair Concentricity gauge and the worst one had a total runout of 0.004”. Usually when I form brass I don’t even bother checking because it needs to be fireformed first. A shout out to Redding on their dies on this one
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RL338

Handloader
Mar 23, 2017
2,139
3,217
In closing this project I got some on paper today.
First I got into the range parking lot , driveway opened but lot not plowed.
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Rifle set up on bench , poor lighting in picture.
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I just loaded some Speer 270gr BTSPs (2780 fps) and Hornady 300gr BTSPs (2670 fps) with Hybrid 100V and Fed 210. Couple of groups.
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Boy I wait after I get the brass fireformed and start real load development. One little issue I had today is that the brake kept coming loose. One wrap of teflon tape will solve that. Most of my braked rifles have that done.
I’m also pleased that the cheap Vortex Iron Peak 4-12 scope that came with the rifle holds.
The brake is amazing in reducing felt recoil by a mile. The rifle weighs 10.2 lbs and feels like my 257 Wby or a little less.
I really enjoyed this project and how speedy I got my barrel , and now I have an amazing rifle.
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JD338

Range Officer
Staff member
Nov 4, 2004
23,245
4,470
Awesome rifle. .5 MOA with fire forming loads and a new barrel is very impressive. I'm thinking that you should get 2850-2900 fps with the 270 SPBT which would be a pretty flat shooter.
The best is yet to come. Nicely done!

JD338
 

IdahoCTD

Handloader
Nov 4, 2004
2,565
270
How has the Petersons brass handled the pressure? It works good in my 300wm but I haven't used it in anything else. I have always shot Winchester in my 375-358STA but I bought 400 of the Peterson wildcat tubes to try. I shoot 89grs of IMR4350 with 250gr Sierras at 3085fps in mine. It's a hot load but it has always shot well in my rifle.
 

RL338

Handloader
Mar 23, 2017
2,139
3,217
I’ve only ran 25 rounds through so far. I’m using mild charges yet , need to iron out some wrinkles in some of the cases. If I do it over again I would get a 416 Rem FL die to start the necks. I tried my 416 Wby die and it was hard to keep the case centered in the die. Once I get the rest fired then I’ll up the charge.
On a side note your brake works wonders , I’m looking to add some more👍
 

IdahoCTD

Handloader
Nov 4, 2004
2,565
270
I used my 416 Rem die to do the first step. A 375H&H shrinks it a lot, with the body taper it has, and tends to wrinkle the neck and shoulder.

Good to hear on the brake.
 
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