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Wow! I need 50+ gr of RL-15 to break 2000 fps in the 9.5x57 M-S, which has smaller case volume (w/ 270gr RN).

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Therein may lie at least part of our difference. My Bertram 375x2 1/2 FNE has a capacity of 65.5 grains of water, and my Bertram 375x2 1/4 Rimless Nitro Express (9.5x57 MS) has a capacity of 68.0 grains. Maybe your brass has greater capacity than mine?

I have used reformed 40/70 Sharps Straight brass for the 375x2 1/2 FNE that has a capacity of 71.0 grains of water, and this does require adjustment of charge weight with Varget (I have not used this brass with RL 15 though).

Don't forget to post a pic of your rifle !!!

Good shooting,
Jim

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I guess I stand corrected. I measured my 375 FNE brass today (formed from Shiloh 405 Basic), and the H20 capacity is 67.5 gr. For 9.5x57 (formed from 9.3x57), the capacity is 68.6 gr. I also slugged my bore on the 375 FNE, and it comes out to 0.375" across the lands and 0.380" across the grooves.

Also, I shot the 375 FNE at 50 yds, using Hornady 270gr RN and 51 gr of RL-15. I was hitting about 11" high. I don't think increasing the charge will help, so I'll try dropping it to see if I can get it to hit point of aim.

Still working on the pictures! (I don't have a digital camera yet)

Thanks,
Washougal Chris

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Chris,

That certainly explains a lot of things. Have you considered trying .377-.378 diameter bullets in your 375 Flanged? These normally are for the 38/55, but should work OK at 375 Flanged velocities (be sure that your chamber neck is large enough to allow the release of the bullet properly-you may have to turn the necks) . My H&H double (not the bolt) has almost as large a groove diameter as your William Evans, and I have used these bullets fairly successfully in it. I even got Hawk to make a run in 320 grain weight to try and find a regulating load, but I eventually had to get a swaging die (actually a point forming die) and press from RCE to do my own with a relatively blunt round nose configuration.

I got some .379 diameter 245 grain FP cast bullets from Midsouth Shooters Supply, but I haven't tried them yet. I think you can find someone to cast some .380 bullets as well, assuming they have a mold that will drop this diameter unsized. If you find something along these lines with a gas check please let me know.

Using a bullet that is closer to groove diameter will affect POI to some extent (although often higher), but if you are 11" high at 50 yards I wonder if your rifle was sighted for the 320 grain load like my double. At the very least try the 300 grain Hornady RN with 40-44 grains of RL15, and I think that you will be much closer to point of aim.

Let me know how you are doing with it. Man, these things are fun to play with .

Jim

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Not sure how I've managed to miss this thread 'til now, but I can weigh in with a bit of .375 2-1/2" data from my two rifles. One was (alas, sold in a very bad year) an H&H '92 Steyr like yours that handled higher pressures, though needing shorter OAL, than my current Lancaster hammer single. The bolt gun liked pretty hot loads with Re7 and 235 grain Speers, loads that were way beyond what I use now.

My current favorite load for the Lancaster is 44 grains IMR3031 with the 270 Hornady RN seated to 3.375"; these give right at 2000 fps and shoot exactly to the sights - and are very mild and easy on brass. I've tried Wright's 49 grs of Varget with the same bullet seated to 3.30" and they clocked 2170. They also extruded the primers back too much into the slightly oversize firing pin hole and I stopped using that load. The other load the Lanc likes is 45 grs IMR4895 at 3.30" for a bit over 2000fps. This Lancaster, BTW, has conventional rifling in its 28" barrel, not oval bore, and I will sheepishly admit to not having slugged it to find its bore and groove diameters.

The .375 2-1/2" is a favorite of mine and the Lancaster is the one rifle I can't seem to miss with. I'll post a picture when I can remember where I filed it...

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Steve,

I love this cartridge as well. You will appreciate the frustration that I went through with my H&H Dominion double. It had the larger groove diameter as I mentioned, but it also had extremely long throats plus a tight chamber bases. Initial individual barrel groups were three to four inches apart at 30 yards, and got worse at 50 (four to seven inches ). After trying about every trick known to man it still wouldn't bring the barrels together. To make a long story short, I now use reformed 40/72 brass from Buffalo Arms (I reduce the rim thickness in a mini-lathe, and resize in RCBS dies as my CH-4D dies were too large at the base). With the long throat (actually like a long neck) I am able to leave the brass at 2.625", but I have to turn the necks to reduce thickness for use with .378+ bullets. Case capacity is 71.5 grains of water.

Even though it was proofed for the 320 grain load it groups better with lighter bullets. I swaged various factory bullets up to .378, but you will never believe the bullet that groups best with this rifle. I sure didn't think it would work, but when I was playing around with the swaging die I ran a few through it just to see what they would look like when they came of the die. The bullet is the 250 grain Sierra Boat Tail . It comes out of the die looking like a round nose with a small bevel on the base (you would never guess that it was originally a boat tail), and it weighs 245 grains after trimming all the extruded lead.

I have to seat the bullet to 3.448" OAL, and with the increased case capacity and long OAL I have to go all the way to 54.0 grains of RL15 to bring the barrels together ( WARNING ,this is way too much powder to use in standard length and capacity 375x2.5 brass and in weaker actions-end of disclaimer ).

As luck would have it, I had it at the range this afternoon and shot this load at 50 yards. I wiggled on R2 but excluding that the other three shots were in 1 1/4" (the wiggle blew it out to 2 3/8"). At 40 yards it stays around an inch if I do my part. It will do almost as well with reswaged Speer 235's. This was a particularly satisfying conclusion to my search for a good load. The amazing thing is that it actually shoots better individual barrel groups with unswaged .375 diameter Speer 235's than any of the .378's, so maybe there is room for improvement if I can master the swaging technique a bit better. Even so, this has a particularly satisfying result in my search for a good load for this nice old double.

Can't wait to see a pic of your Lancaster!!!

Jim

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Using a bullet that is closer to groove diameter will affect POI to some extent (although often higher), but if you are 11" high at 50 yards I wonder if your rifle was sighted for the 320 grain load like my double. At the very least try the 300 grain Hornady RN with 40-44 grains of RL15, and I think that you will be much closer to point of aim.

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