So it begins. I sent off my old Sedgley Springfield to JES Reboring earlier this fall and got back a 375 Whelen. I opted for the standard 375 Whelen. It seemed appropriate in the Sedgley. Before anyone swoons over the Sedgley, it had been bubba'd pretty badly with poorly done side and top mount holes for scope bases and the bolt would close on a no go gauge. Plus I wanted a 375 Whelen. The rifle cost me $180 and the rebore $225 so I ended up with a pretty reasonably priced 375 Whelen.

I spent quite a bit of time on line finding bullets to test. I may have gone a little over the top. Missing from the picture are some 250 grain Sierras and 4 more boxes of Hornady 270 grain round nose.

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I located 200 rounds of some LC 76 match brass. I already have a 35 Whelen so wanted to avoid any confusion by not using any of that brass. This was all unfired match brass. I used my 30-35 and 35-416 expander die to open it up and then ran it through a CH-4D 375 Whelen die to neck size just enough to make a snug fit in the chamber. I had one split neck out of 200.

I had to trim to 2.220 to square up the mouths. That's a bit shorter than the 35 and 400 Whelen's trim length of 2.495.

My choice of powders was limited to what I had on hand. Powder availability has been sketchy at best here in Alaska. I had plenty of BL-C2, 3031, 4320, AA2495 and some RL15. The RL15 is running low so unless I come across some more it's use in development will come to a halt.

There is precious little data for the standard 375 Whelen. A fair amount exists for the 375 Ackley Whelen and the 375 Hawk/Scoville but not much for the standard version. Data exists however, for most of the same bullet weights in the 35 Whelen. Knowing that the same bullets weights of a larger diameter are going to produce lower pressure given the same loads, I extrapolated data from 35 Whelen data.

My first trip to the range was yesterday and it went well. I was testing Speer 235 grain bullets with the five aforementioned powders. All were primed with Federal 210 primers. I expected this bullet to easily crowd 2600 fps. My BL-C2 loads produced the highest velocity and came the closest to meeting that velocity. It was clear to me that I estimated on the low side of all my test loads. None of the 100 rounds I fired showed any evidence of excessive pressure, no cratered primers, no primer leaks or blown primers and no shiny spots on the base of the case. Bolt opening and extraction were effortless in all loads tested.

The top loads were as follows (I worked up from well below these charges);

BL-C2 62 grains 2574 compressed
2495 54 grains 2324
3031 54 grains 2510
4320 57 grains 2482
RL15 59 grains 2464 lightly compressed

I still have much work to do. I had hoped to sort out one or two powders that showed great promise but they all shot with relatively good accuracy. AA2495 and 4320 showed the best accuracy but not a great deal better than the others. 3031 was a bit inconsistent with accuracy, one good group and the next erratic.

All my initial groups were 4 shot groups at 100 yards. The rifle wears a 24 inch barrel and is scoped with a Leupold 3-9x compact. All loads were shot over my PACT chronograph. I used a PAST recoil shield and a slip on recoil pad to reduce shooter fatigue. It worked very well. I was tired from the recoil but not sore after 100 rounds.

I will continues to post more as I have more data.

Mart



Chronographs, bore scopes and pattern boards have broke a lot of hearts.