.375 HH , 19 inch bbl rang report

[farshot]

After trying to get some velocity out of my rifle, I decided to sit down and make a few of each and see how it all turns out. The results did surprise me a bit. I had thought the fastest powders would be the better velocity , yes and no.

Of course these are my results and be careful with any you may try. All powder was weighed for each charge.

Rilfe is a very good condition modern Heym 20G, 19 inch bbl (someone shortened it - good job), tight chamber with good freebore, plunger type ejector. All Barnes 270 gr TSX bullets, all set a 1/10 inch below SAMI max OAL to fit in mag nice. All use Fed 215 primers and Federal brass partially sized to fit snug in chamber.
All good accuracy (less then 1/2 inch) at 40 yds with a couple that I will mention which was very good. (one ragged hole).
Chrony chronograph.


Win 760

max used was 80 gr for 2450 ft/s, no pressure signs, but getting over book value

Varget

max used was 69 gr for 2442 ft/s , no pressure signs but for a slightly harded bolt lift

IMR3031

max used was 65 gr 2445 ft/s, very good group of 3 shots, no pressure signs

H4350
79 gr 2410 ft/s , primer flattening a bit, same hole over 2 shots

80 gr 2437 ft/s -- primer flattening and stiff bolt - same hole

Win 748

81 gr max, 2620 ft/s, no pressure signs, large muzzle blast, same hole over 3 shots

RL 15
75 gr 2600 ft/s same hole 3 shots, slight ejector mark
76 gr 2620 ft/s same hole, slight ejector mark, no lift resistance
77 gr 2642 ft/s same hole, bigger ejector mark, slight bolt lift resistance-stop

Given my somewhat limited results, I expected W748 to be a good powder in the short bbl, but did not like the muzzle blast - I will consider the loads tho.

But i like the RL15 once again, 77 gr is too much, probably 76 grv is too much, but 75 or maybe 75.5 gr is a keeper load for my use. RL15 and W748 were the only ones to break out of the 2440 ft/s range.

I had thought the IMR3031 was going to be a winner or the H4350, they work great in my shorter 30-06s.


I will test at distance next go-around now that I have narrowed it down.
Hope this helps someone else

Remember to use very carefully!

 

[Boomer]

Gernerally speaking, the powders that work best in the long barrel also work the best in a shorter barrel (within reason). For the .375 H&H this is powder in the Re-15 range with lighter bullets and H-4350 range with heavier bullets, which your velocities with the 270 gr X's seems to confirm. With a 300 gr X bullet, 760 I consider superior to 4350 due to it's higher loading density.

I would not be inclined to stick with a load that resulted in either a stiff bolt lift or one that left an ejector mark on the case head. That tells me that in your rifle 74 grs of Re-15 might be more prudent than anything hotter.

 

[farshot]

You are right Boomer - im going to back up to 73 gr RL 15 and see where it lands me -

I may have to try te 300 gr with powders you suggested , I figured that the 300 gr would crowd the capacity of the case in the already tight mag well. I got to say that the BRNO 602 has more room for the OAL in te .375 then this Heym. But the eae of handling is quite remarkable compared to a full sized BRNO 602.

 

[303carbine]

I read somwhere that IMR 4064 was the powder that a lot of the .375 H&H factory ammo was loaded with. I got very good results with 4064 and accuracy was into an inch with the 270 grainers.

 

[beretta boy]

IMR 4350 may get you where you want to be with 270 grainer's too.

 

[svt-40]

How was the perceived recoil?

 

[FullDraw]

375 H&h

I had the best luck with 74 grns of RL15 in my Brno 602 with a 25" barrel.

F/D

 

[farshot]

Recoil was fine - a nice big blast tho, much more with the ball powders. Recoil of a .375 is like a bigger shotgun. A .340 weatherby etc has a much harder "kick".

With this short bbl - there is more muzzle flip tho, but it is a trade off cause, I have got to admit, it is so nice and handy and i really dont ever expect to take more then 2 shots at any given time.

And please be clear __ I dont suggest the loads above , they are merely for illustration as to what you get with those particular loads in that short bbl rifle --
they were mostly all on the edge or over the edge.

 

[MTM]

Just working up this years hunting load for my Mod.70 with 22" barrel. With the 270 TSX 74-75 grs of Rel.15 were fine. No ejecter marks and primers and bolt lift were normal. Didn't go higher as I know this is near max. Started with the 300 TSX this weekend. 78 grs of 760 gives normal pressure and is accurate. Didn't fire a lot of groups but did manage a 1 1/4"er at 200 yds. With Rel.15, 71 grs. gave me a 1" group. It was too hot out to screw around with more groups. I've got some loaded and will shoot them this week. Rebedding with pillars has fixed this tupperware stock and it looks good to go.