.375 H&H 300g bullets best velocity

[benchracer]

Word came from CZ this spring that they are ceasing production of the 550 Safari Magnum actions. I had been sitting the fence about making changes to my rifle, but CZ's announcement made me decide that I had better move forward while aftermarket parts (particularly stocks) are still available.

I went with a Bell & Carlson synthetic stock, had the action drilled and tapped to accept a picatinny rail, and had the barreled action, bottom metal, and bolt shroud finished in Tungsten Cerakote.

 

[benchracer]

Planning to mount an optic more suited to North American hunting, though I will hang on to my Meopta for dangerous game hunting.

I intend to develop a 300 grain Swift A-frame load, for dangerous game, and zero my iron sights with that load before adding another optic. Once I have the right scope mounted, I am seriously considering some load work with the Cutting Edge 325 grain Lazers.

 

[fiftybmg]

BTW, Bryan Litz's testing of the CE 300 MTH shows a .331 G7 bc, which corresponds to a G1 bc in the mid .6's. That is significantly lower than the .750 G1 bc listed by Cutting Edge, but it is still well above anything else currently available in this weight range.

We have a range of monos called Peregrine. The BC numbers are here

Peregrine Glider BC Chart

The only limit to these for 375 H&H is AOL, they do not fit in the magazine, and if you have a mauser style bolt, it may not like being single fed.

 

[fiftybmg]

With 300 grain bullets, RL-17 has done the best for me. There is more speed to be had, but the node is around 2800. I am happy with how the 79.5 grain load is shooting @ 2783.

The 2800 fps number in the Nosler guide is not for 300 grainers, it is for 260's.

The 2800 number quoted here seemed a bit high, because I know that the 375 RUM is rated for 2800 fps using 300 grainers, and when I load 375H&H with 300 grainers, it's a calm 2200 fps, normal loads being closer to 2400 fps.

However you got that result of 2783 fps with 300 grains, it is far beyond the safe pressure limit of the cartridge.

 

[benchracer]

The 2800 fps number in the Nosler guide is not for 300 grainers, it is for 260's.

The 2800 number quoted here seemed a bit high, because I know that the 375 RUM is rated for 2800 fps using 300 grainers, and when I load 375H&H with 300 grainers, it's a calm 2200 fps, normal loads being closer to 2400 fps.

However you got that result of 2783 fps with 300 grains, it is far beyond the safe pressure limit of the cartridge.

The data you are quoting is only a good measure of pressure with the same bullets, same powder, and same OAL listed in the data. Published data for the bullets and powders I am using does not exist for the 375 H&H. You clearly have not read carefully enough to make the judgement you are making. In the simplest of terms, you do not know what you are talking about and you are wrong.

 

[808mike]

Tagging in

 

[fiftybmg]

You clearly have not read carefully enough to make the judgement you are making. In the simplest of terms, you do not know what you are talking about and you are wrong.

You are entitled to say I am wrong, and I am entitled to say your loads are recklessly unsafe.

The impression you are giving is that you are quoting numbers from a software program, not your actual chrony data.

I sincerely wish you good luck.

You have no business claiming numbers that translate to unsafe data on a public forum , where the less experienced often come for advice.

 

[benchracer]

Your accusations are carelessly and ignorantly made. I am not going to waste my time defending against them. If you wished to make a constructive contribution to this discussion, all you had to do was ask questions (though the answers to such questions have likely already been covered in this thread). You chose not to profit from the discussion by hurling accusations, rather than seeking to understand what, why and how.

I am well acquainted with what is, and is not, my business. Bye Felicia!

 

[CUTTER1]

I HAVE FOUR 375'S. 2 ARE H&H, ONE A RUM, AND A 375 AI.
JUST RECENTLY ADDED A BLASER R8 IN 375H&H (WITH 300 RUM & 257 WBY BARRELS) FOR AFRICA! EVERYTHING FITS IN CUSTOM CASE ALONG WITH 3 SCOPES AND MY 470NE DOUBLE RIFLE (EMERITES AIR ALLOWS 70# IN B CLASS)
THE BLASER SHOOTS BOTH A-FAME 300gr AND BARNES 250TTSX UNDER 1/2" WITH 4350!
THE RUM WILL SHOOT 300gr A-FRAME AT 2825
THE AI DOES 2700 AND YOU CAN SHOOT PLAIN H&H IN A PINCH
THE BLASER IS 3# LIGHTER THAN THE RUM AND AT 2500FPS WITH A-FRAMES RECOILS COMPARABLE TO THE RUM
4350 IS VERY TEMPERATURE STABLE AND FOR ME THAT IS IMPORTANT
EACH OF THESE GUNS HAVE BEEN RANGE VERIFIED TO 500 YARDS AND THE BLASER TO 800 WITH 250TTSX

 

[benchracer]

I finally stretched my developed load with the CE 300 MTH bullets @ 2780 to 1000 yards. I don't have target pics to show. This was just proof of concept. I am still learning to control the rifle from the bench. The load performed well and produced a consistent waterline, but it took me awhile to get the windage dialed in for conditions. I hit a reduced steel silhouette target 5 times in 20 tries. I need more trigger time, but the system itself is working. I have two bullets left. Time to order more.

This is the scope I was using for the test:

https://www.primaryarms.com/pa-3-18x50mm-illuminated-ffp-rifle-scope-with-acss-apollo-6-5cm-reticle

I originally bought this scope to use on my 6.5x55 (it worked very well for that purpose). As I was reading the zeroing instructions, it dawned on me that this scope would work on anything that had a similar trajectory. I started running some what-ifs through JBM Ballistics and realized that my CE 300 MTH load was a very close match to the Creedmoor trajectories for which the reticle was designed. A quick check of the scope specifications showed a generous enough eye relief to make me comfortable trying it on my 375 H&H. I mounted the scope. Zeroed at 100 yards. Took a few shots at 500 to fine tune the zero a bit. Then, moved out to 1000 yards. Just as JBM had predicted, my 1000 yard trajectory was true to the reticle.

Over the course of this entire experiment, I have learned that conventional bullets, like the 300 grain Sierra Game King, can be loaded to approximate .308 Win trajectories and the Cutting Edge 300 MTH can be loaded to approximate 6.5 Creedmoor/.260 Rem/6.5x55 trajectories. Combine loads of either type with the appropriate BDC reticle, and you will have a versatile, accurate setup capable of quick engagements both near and far.

The idea that conventional loads approximate .308 Win trajectories has me considering use of a tactical type LPVO with a .308 BDC for use out to 600 to 800 yards. I will be trying that idea next.

In the beginning, I was experimenting with a combination of newer powder and newer bullets to see what was possible. Along the way I stumbled into the idea of adding some newly available optics to the mix (an idea I had not previously considered and did not anticipate). Anyway, I hope this will be food for thought for anyone interested in the general concepts I have explored so far.

Since I began this thread, 1000 yard shooting has become rather unremarkable. The feats being accomplished by ELR shooters continue to push the boundaries of the possible. They deserve to be celebrated for that. For my part, I am still working on becoming a competent 1000 yard shooter. I continue to enjoy the learning process as I go, though the end goal is not significant to anyone but me.