Does anyone know what the concave section is for on the stem of an H&I die?.

[samari46]

Was cleaning up some of my older H&I dies and noticed they have a concave section on the part where the bullet base goes. And what purpose does it serve. Been casting since the early 70's and noticed it but never thought it did anything. Only thing I can see is that the outer edge of the concave section might help with setting the gas check straight when sizing and lubricating a bullet. Inquiring minds want to know. Thanks, Frank

[Bazoo]

I don't know for sure but I have always thought it was to ensure the edge of the bullet was resting on the pin. A sharp edge seals better so lube dont flow between the base and pin.

[Rich/WIS]

Ditto, also helps it you leave a small bump when cutting the sprue. The old NRA Reloading guide had an article about taking out the pin and chucking in a lathe and cutting a recess in the center to trap any lube that squeezed under the bullet base.

[samari46]

Two great answers. Thanks a lot. Frank

[Bazoo]

RCBS H&I dies have a hole down the center pin.

[Larry Gibson]

Gives a place for an uneven sprue cut to go so lube, under pressure in the lubrasizer, won't go under the bullet.

[samari46]

Thanks again,all of your comments and suggestions are very much appreciated. Frank

[Uncle Grinch]

I think it also gives a firm edge to seat gas checks.

[Bazoo]

Not to mention gas checks aren't square on the edge but slightly rounded. I imaging it helps with getting them seated.

[samari46]

I have an older Lyman sizer/luber and sometimes have to crank down on the ratchet to get a good flow of lube to lubricate the bullet. Which means I have to wipe the baby's bum for each bullet.And was thinking of turning off the concave at the end. That is why I asked the question. Thanks for your help. Frank