I am a novice at reloading, and new to reloading 375 H&H. I tried to load a 300 gr TBBC over 79 gr of H414. I was trying to get a cartridge length after loading of 3.6. Before I could get their the bullet would hang up in the die, stuck on the seating ram. Any thoughts as to what I'm going wrong?

Sounds like there might be a problem with the seating stem/plug, or maybe the wrong one for the 375. Disassemble the die and take a look at the seater plug. Also, what do the tips of the stuck bullets look like?

You probably need to open up or polish the area in the seater plug that is contacting the ogive of the bullet. Take it out and gently chuck in a drill press (not too hard or you will bugger up the threads) and turn the drill press on and polish the inside a bit with a stone. It doesn't take much and that should get you going.

The seating plug contour is wrong for the bullet you're using. Call whatever company made your die, tell them the bullet you're using and they should be able to sell you the appropriate seating plug.

What has been said by the others is probably gospel but make sure you have an adequite ID chamfer . seems that you must be getting a large upward force from some where. Is your expander under size?
Could the bullets possibly be chanting? roger

Try to spin your case as you raise the ram. This will help stand the bullet up straight so it will miss the hang up edge.

To spin just pull a finger past the case head.

This is very basic, actually extemely basic, but if you have the die set to close to the ram, or too low in the press, you could be crimping the case before the bullet is seated completely. DW

Thanks for the help. It looks like there were two factors, one: I did have the die screwed down too close to the ram, and two: the "cup" on the seater plug it too tight a fit. I moved the die up a little and switched to an old 375 H&h die that I came across in some stuff that I inherited from my brother and everything is working well.
Thanks again for the help.