H&I (Lyman Size Die Observation

[shell70634]

While cleaning some sizing dies I noticed the surface of the center rod was concave on some of them. I've been using them for years but this is the first time I noticed. Is that a design feature? If so, what is the purpose. Not all are like that.
I was having trouble getting a good gas check attachment with my 376 so I just PC'd them. I turned it flat with the lathe but haven't tried it yet.

[243winxb]

For a bevel base bullet or to collect excess lube? Guessing. I dont know.

[Dusty Bannister]

This is common and is to allow any slight sprue nub to prevent the bullet base from making intimate contact with the Center push out rod of the HI die. Many will intentionally counter sink the center of this rod and that will insure that the outside perimeter of the base of the bullet is flat and square.

[dannyd]

It's normal and more so on the older one's.

[poppy42]

Yep most of mine are like that

[poppy42]

While cleaning some sizing dies I noticed the surface of the center rod was concave on some of them. I've been using them for years but this is the first time I noticed. Is that a design feature? If so, what is the purpose. Not all are like that.
I was having trouble getting a good gas check attachment with my 376 so I just PC'd them. I turned it flat with the lathe but haven't tried it yet.

Whey didn’t you just turn the rod around? Although I doubt that is why your gas check isn’t seating,

[JonB_in_Glencoe]

Whey didn’t you just turn the rod around? Although I doubt that is why your gas check isn’t seating,

Because most a rounded on the other end

[gwpercle]

If you don't want to use the concave surface ... remove the rod and simply install the other end ... the three I'm looking at are concave on one end and flat on the other ... you get's to choose what you want to use .
I never had any problems with the concave end ... just sized the boolits and didn't put excess pressure on the lube handle .
Gary

[Sam Sackett]

I noticed that I get a little less leakage when lubing bevel base bullets using the dished end. Now I just leave it installed that way. No issues with checks or flat based bullets either.

Sam Sackett

[TD1886]

Just like the one member mentioned about the sprue and also it makes for a better seal contact on the bullet to keep the lube from sneaking by. I believe it was in the old NRA cast bullet book about concaving the top of that punch and also drilling a hole all the way through of a very small diameter to give the lube that gets under the bullet someplace to leak off too. I also modify the flat nail head pin that pushed the die piston or plunger up along with the bullet by cutting a + in it with a small triangular file to let that lube that goes down that bleed hole I mention a place to get out. No more bunches of lube under my bullets!