OAL for .375 H&H Magnum (advice needed)

[duckey]

So today I made a homemade bullet seating depth gauge with a new piece of brass that was resized and trimmed down. after placing the shell in the gun and closing the bolt and removing the case I saw that the 235 grain Speer Hot Core Semi Spitzer was only seated maybe 4mm (1/8"ish) into the case neck. This doesn't seem right to me, and I know that the bullet tip is right on the lands but even if I set the bullet deeper .003 to .005 or so that still doesn't put the bullet that much deeper. I know the tip will probably not come out once crimped in the case but I feel that it is to shallow in the case. The OAL came to 3.774.5". Alliants load data (I will use RL-15) says min OAL is 3.6". Am I safe to assume the bullet is not seated deep enough in the case? I know a heavier bullet probably would be deeper.

[Freeandcold]

I don't have manuals or my records in front of me. But, if my failing memory is correct, the max OAL is in the 3.6 range... For me this is a magazine length restriction. And I have not experimented enough with longer OAL to comment. But, 1/8" seems a bit on the side of not enough...

[rmcc]

3.600" is the standard OAL length for the 375 H&H. Sounds like you have a "free bore" issue. With the recoil this round generates, my rule of them is roughly a caliber width depth in the case. But, that is just me. Playing around with that bullet, there is .297 in the case and maintain the 3.600" o.a.l.


rmcc

[duckey]

Thanks for the advice Alliants "min oal" listed has got to be a type O. Most oal's I have been seeing are in the 3.54 ish range. Maybe, unlike other rounds you don't have an option to mitigate bullet jump?

[historicfirearms]

Many 375h&hs have generous throats and I believe this is what is causing your concern. They are made that way to ensure reliable operation for dangerous game hunting. The general rule of thumb is to seat a bullet at least a caliber deap, so .375" in this case, just a guideline and not set in stone.

[fouronesix]

I don't know about minimum OAL, but 3.600 is about it for maximum OAL in most standard long magnum length actions.

historicfirearms info is correct.

I wouldn't worry about the bullet jump because the cartridge/gun are not designed for target shooting where it's common to seat bullets right up to or even make contact with lands. Also, some 375 HH ammo is loaded with round nose Jbullets up to 350 gr so require a longish throat for those longer RNs.

If the throat (freebore) is groove diameter up to about groove +.001, there will be little if any loss in practical accuracy. Plus any correctly designed dangerous game rifle should have some freebore for at least a couple of reasons. Handle a variety of long RN bullets and minimize cycling failure because of pressure spikes in extreme heat. The freebore helps prevent high pressure spikes.

In the 375 HH, I'd just load the smaller Jbullets to either- 1 caliber depth or the full length of the neck. Because of recoil with full house loads, you'll want as much neck tension as the neck length will allow- base of bullet seated to the junction of shoulder and neck. Or if bullet has a crimp groove- seated to crimp into that groove. Mild cast loads are of course another matter.