.375HH short bbl load recipes?

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farshot

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I have a .375 HH , 18 1/2 inch bbl that i am tring to find a good load for.

I prefer 270 gr Hornadys as they appear to fit the well in the Heym rifle the best. I have tried up to 81 gr WW 760 with mag primer for 2400 ft/s and very good accuracy and no extraction issues but I think that is the max I can go (by looking at the primers).

Do you think RL 15 would be worth trying or am I at the velocity limit with the shorter bbl?
any other suggestions to try out?
 
My Winchester Model 70 is the shortest of my .375's with a 20.5 inch barrel. It does allright with a max load of IMR 4064 behind a 300 grain Hornady.

Given your short barrel, it's pretty clear that your options are limited to faster-burning powders. Reloder 15 or Varget will probably be OK.

There isn't much doubt in my mind that you will be maxing out on your velocity due to the limited barrel length.

Have you tried 300gr bullets in your rifle?
 
farshot said:
Do you think RL 15 would be worth trying or am I at the velocity limit with the shorter bbl?
Click to expand...
I got over 2800fps with my 21" 375/338 using RL15 and 270gr Hornadys and the 375H&H has a greater case capacity.

375CT2866fps.jpg
 
300 gr bullets will crowd the mag well and I thought it would take away powder space.

Hmmmm - my .375/.338 does 2670 with 71 gr RL15 in a 22 inch bbl - now you have me wanting more out of that rifle as well!

i will give rl15 and 4064 a try
 
farshot said:
Hmmmm - my .375/.338 does 2670 with 71 gr RL15 in a 22 inch bbl - now you have me wanting more out of that rifle as well!
Click to expand...
I'm not planning on using that 74.5/RL15 load.

I didn't see any extraction/pressure problems, but 2600-2700fps is the same as 375H&H and lots of velocity for the caliber and would be easier on brass.



.
 
Short barrel, long barrel- Makes no difference.

If you pick a load that has the highest velocity in a 24" barrel, then chop off 6" of barrel, it will still have the highest velocity in the shorter barrel.
 
Another confirmation of Gatehouse's post.

I have owned and used three 20 inch 375 H&H rifles over the years. Chronographed all of them before and after shortening the barrels. All three got the highest velocity after shortening the barrels with the same loads as they did before.

Furthermore, all three lost less than 50 fps in shortening the barrels from 24 to 20 inches! Not 50 fps per inch, 50 fps total loss in velocity.

High expansion ratio is a wonderful thing. :)

Ted
 
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Almost 10 years, do I get a prize? Working up a RL15 load under 270gr Hornady in my 20" 375 H&H. Depending on results I may stick with Varget for hunting loads because of reduced temp sensitivity.
 
RL15 and Win 760 produce similar velocities.

But, based on my experience, RL15 is about the ultimate powder for that 275 gr bullet. So yes, worth a try.

Go with which ever one gets the best accuracy.
 
CZ550 375 H&H 20" barrel, 270gr Hornady 74grRL15 2610fps@ +1C this am. 270gr Speer over 75gr Varget went 2710@ -8C the other day. As near as I can figure I lost about 120fps cutting from 25 1/2" to 20". No visual or felt signs of pressure. This particular rifle seems a bit faster than some others.
 
Considering to try 270gr TSX bullets in my 375 H&H Sako 85 Kodiak which has 21-1/4" barrel. Reloder15 should be a good powder and Barnes #1 lists 2784 fps maximum from a 26" barrel.

Barnes #3 lists the same load and speed from a 24" barrel. :confused:

Based on your results of about 20 fps loss per inch of reduced barrel length, then I should expect 2600 to 2650 fps as I safely work up an accurate load (assuming my rifle fires the TSX bullet accurately) to near maximum safe pressure. :cool:
 
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