How necessary is it to put a crimp for the 375 H&H? And I have settled in on using 300g TSX, they seemed to have grouped the best in my rifle. If a crimp is necessary, my next question is, how important is it to make sure the crimp takes place in one of the cannelure groves of the TSX? I thought I read something that talked about if I was using the Lee Crimp Die, it isn't the most important thing to crimp exactly in the cannelure, and I just wanted some opinions on it.

If you have adequate neck tension it is not necessary. If it makes you feel better, go ahead. My M70 prefers the case mouth even with the first groove on TSX for the most reliable feeding so that is where the crimp would go for me.

Not necessary with the long bearing surface, unless you are way long. Mine are seated deep and crimped at the last groove. A long jump to the lands worked best for me with 250-grain TTSX's in .375 Wby and I still have enough RL-15 in it to reach the bullet base along with good speed. Lee Crimp Die crimping deep in the driving band / cannelure makes sense to me...

I use the 300 TSX out of one my 375s and one I load for a friend. I crimp lightly in the last groove with a Lee crimp die. Accuracy is exceptional out of both rifles. I use a 300 Northfork out of another 375 and crimp those too. I don't think it is really necessary but it is cheap insurance to make sure rounds in the magazine don't jump in cases and subsequent feeding or extraction problems.

I asked this very question to Nosler a few years ago. They told me that they felt 375 H&H and larger should be crimped. I have crimped them ever since with the crimp feature in the RCBS die. Accuracy has been superb.

Thanks for the feedback. I'll give them a slight crimp and see how it goes.

Measure OVL of loaded and then the bottom loads in the magazine after 2-3 have been fired. You'll find out whether they slip in deeper that way. I sure would crimp all hunting loads. You don't want feeding or high pressure problems when you really can't afford to have them happen.

George

I crimp for my M70 375. It feeds much better when the round is crimped. I'm using 270 TSXs and crimping into one of the grooves. The Lee crimp die is set to give a smooth transition from the bullet to the case so there is nothing to hang up on. Preventing bullet slip is a secondary function for me.

I think crimping helps TSX loads. I have loads thus crimped for a 30/06, a 375 H&H Magnum and a 378 Weatherby Magnum that have provided excellent accuracy.

I crimp everything from my 243 Winchesters to 458 Win Mag. I've always had better accuracy and lower SD with crimped rounds. With that said, for bullets with groves or cannelures I try to use those. I use the Lee crimp dies for all my loads.

I crimp my 375 H&H loads about .005" using the Lee factory crimp die. I don't use the cannelure.

I also crimp everything, and did the 375 when I had one.

I only crimp for lever and autos..Never on bolt actions..What I will do on a big bore is turn about 1 to 3 thousands off of the expander ball in most cases, and mostly use a powder that fills the case at least to the neck/shoulder junction..Never had a problem..recoil moves bullets in 99.9% of the cases by being left in the magazine too long after many shots are fired, mostly in DG culling operations, top loading on the magazine puts a lot of stress on the bottom rounds.

As to accuracy gained by crimping, I have not found that to be the case, quite the opposite..but as in such contested conversation in gundome, to each his own is the proper answer.