Dangerous loads for Dangerous Game (??)

I am hoping to get some wise words from experienced reloaders on DG loads for my 375 H&H.

I went on a DG hunt in Zimbabwe recently, taking my 375 H&H, and my intention was to use Woodleigh 300 gr RNSP bullets and Woodleigh 350 gr solid bullets. I wanted to use 350 rather than 300 for solids, as this would give an extra bit of punch, which I felt would be better for Buffalo and Elephant.

Woodleigh doesn't produce a loading manual and their advice is to use other load formula, start low and then work up to get the right speed.

I did this for the 300 gr RNSP and took them up to the speed I wanted without any problem, but when I tried to do the same with the 350 gr bullet I had trouble. I found a 350 gr formula somewhere on the internet (I forget where), clipped a few grains off the maximum powder load and then worked up at half grain increments, chronographing the results. I was using RL 15 powder. However, what happened was that the speed did not increase very much as the powder weight was increased. On adding more powder for the 300 gr bullet I would see a corresponding increase in speed, although if I added more powder for the 350 gr bullet then the increase in speed would only be marginal.

Now, that extra energy has to be going somewhere. If it's not resulting in more speed, it must mean that there is a build up in pressure. I therefore abandoned loading the 350 gr bullet; it seemed too dangerous to continue. I substituted them with Barnes Banded Solids in 300 gr, for which there is reliable load data.

Personally, I think Woodleight has a responsibility to issue some meaningful data, so reloaders can see what the safe parameters are. I think the statement on their web site: "You can use published data from other bullet and powder manufacturers. For safety, reduce by 5% and work up" is feeble and potentially dangerous.

Most reloaders will have a chronograph, or access to one, but very few have access to equipment that measures the pressure within the gun.

This is an accident waiting to happen and Woodleigh should issue load data that is backed up by professional pressure testing.

I would be interested to take guidance and opinion from anyone who has experience or an opinion in this area.

PS The 300 gr Barnes Banded Solids worked fine

....Gloucester I agree 100% they should back there bullets with some data!! They charge a premium price & data should be provided. I own 7 different reloading manuals for bullets & powder producers. Of those 7 manuals only 1 - Accurate Arms even lists a 350 gr bullet. In my experience that is not the manual I would want that info as just about every gun I have used big bullets on I had pressure spikes. I think there powders are a little hot.. That's my opinion!!
For example what if their bullets have a problem like the monolithic bullets by a square & Barnes in the double rifles. Creating pressure problems. Who knows what any of these bullet manufacturers really add to the composition of the bullet - the base or shank..
.. As far as that formula you got for that bullet size off the net yhere is a similar formula I have used fairly reliably wuth cast bullets> But then agaun cast bullets are fairly uniform but if I recall it stated that you took from a known & safe load and calculated this. How do I know a safe load when that bullet manufacturer isn't producing no data?
... That is where the tinkerer or reloader comes in to effect.. I think you made a damn wise choice in abandoning that load. that pressure & speed has to go some where!! If I was you I would write a LETTER AND EXPRESS YOUR CONCERNS, I think the way the lawyers and laws are around guns etc. you would think they would show some responsibility!!

Here is a link with 4 differerent loads for the 350 grain bullets

4 loads available in .375 H&H Magnum with bullet weight equal 350

The powders used are all slower burning than RL-15. However be careful using the above data, compare the two loads with 4350 the one with less powder has higher MV than the one with more powder.

If you can buy VV 560 it may be worth trying.

I once contacted Norma about some issues with their 416 Rem ammo loaded with Woodleigh 450 grain bullets. Like you, the answers were less than satisfactory.

What MV were you trying to reach? Was the bolt sticky? How did the primers look?

That is a big bullet for a 375 H&H and you were very smart being safe rather than sorry.