I found a load that my .375 H&H really shoots well and I'd like to hear some estimates on muzzle velocity.
Gun: .375 H&H Mag, Win M70 24" barrel

Load: 300 grain Barnes triple shock, 71 grains Reloader 15, Federal cases, CCI 250 Magnum primers.

This load is shooting .5" groups (3 shot) at 100 yards with a 2.5-8 Leupold scope.


I think it will come in around 2550 or so?
what do you all think?

I think you are about right, but you have to chronograph it to know for sure.

Every rifle is different, and powder lots are different, and brass varies too.

The little 6.75 pound bare .375 H&H of mine does this:

72 grains of RL-15
24" Douglas barrel
Winchester brass
GM215M primer
300 grain Barnes XBT
MV = 2528 fps, 3/4 MOA for three shots

The TSX may take an extra 1 or 2 grains of powder over what the old XFB took to get the same pressure and maybe a higher velocity and better accuracy.

The Federal brass will take less powder to get the same pressure and velocity that a Winchester case will give. Winchester brass is more roomy internally.

These two differences make me think you have a great load and should not change a thing, whether the velocity is 2500 fps, 2550 fps or 2600 fps.

You have hit a sweet spot there, and I think it is a reasonable load pressure wise, but my guess of the velocity is ... a guess.

Good load.

I use that same load in a 23 inch barreled Whitworth using 300 gr. TSX's and Federal 215M primers. In that gun I got 2512 fps. average for six shots. My son took a 38 inch dugga boy with it 10 days ago.

Geronimo

Going to vary depending on the rifle. My M-70 SS Classic delivered 2604 fps with 300 br TSX's with 68.0 gr RL-15 on Remington cases with WLR primers.

/

Remington brass is thicker and lesser internal capacity, will give a higher velocity with a given charge.

WLR primer? Is that the hottest one we have or was it WLRM, M as in magnum? It has been so long since I used Winchester primers that I forgot. At one time the Winchester Large Rifle Magnum primer was the hottest one available to handloaders.

Nobody mentioned the primer differences yet, but that figures into pressures and velocities too.

RIP,

I think the WLR primer may have been reformulated a few years ago to yield a primer for "standard and magnum loads." Seems to be in the same heat range as a Fed 215 ... as much as you can tell without instrumentation.

Mike,
Thanks for catching me up on that factoid.

quote:

Originally posted by Snellstrom:

This load is shooting .5" groups (3 shot) at 100 yards with a 2.5-8 Leupold scope.


I think it will come in around 2550 or so?
what do you all think?

I will tell you, I wouldn't actually care what the MV was, with groups like that.

jeffe

Jeffe
You are absolutely right!
I really don't care what the MV numbers come out to be the load is definitely working in this rifle. I mostly was wondering what an estimate would be eventually I will chrony the load myself but it will be awhile before I get to do that, my range is crowded this time of year so I don't want to get out and fight for a bench.
The load is working flawlessly in my gun, extracts as easy as it loads, only a slightly flattened primer, and no other signs of pressure. I've also loaded and shot 72 and 73 grains of Reloader 15 and the groups open up ever so slightly to .75" and almost 1" with a little increase in the flattened primer effect. This was all shooting in 85-95 degree heat.
The load of 71 grains has shot 3- .5" groups and 2- .75" groups for me so I am really excited about that and may take that rifle elk hunting this year just to get some "blood" on that load.