Annealed checks and a goofy size punch

[44man]

This is the first time I annealed the checks for this .45 boolit. I had always noticed the ejection punch in this size die was concave and never knew why but it never gave me a problem with hard gas checks. I don't know what die it is, whether Lyman or RCBS because I use both in my sizer and I would have to take it out and clean it to see.
Anyway, when I seated the checks and started to stand the boolits on the bench, they would rock. The check was convex on the bottom and they were not tight. It was funny after I had a few stacked up, I could bump the bench and they looked like a bunch of bobble heads.
I could picture the check driven to the base when shot and making it loose so it would fall off.
I removed the punch and cut it flat in the lathe, polished it a little and had to re-seat the checks by pushing the handle down hard. Now they are flat and tight.
Anyone else ever see a concave punch or have any idea why they made it like that?

[Firebird]

I don't remember where, but I saw this modification recommended somewhere on the internet, maybe the old Hanned Line website? It was actually supposed to give a better seating of the gas check. The theory was to avoid any problem with the sprue cut on the base of the bullet since the punch would only put pressure on the outer edges of gas check.

[lurch]

All the punches in my Saeco dies are concave. Not sure as to the real reason, but would hazard the guess. A lot of times when I let the bollits get too hard before cutting the sprue, I get a little nub sticking up on the base where the sprue plate didn't shear the lead off exactly flush. That little depression would let the boolit rest on the outside of the base, away from the nub. Maybe this would be a little more conducive to getting the boolit in the sizer a little straighter...?

[44man]

I gave that some thought but isn't it better to cut a flat base? The amount of roundness on the bottom of my boolits was really funny. The soft checks flowed into the cavity real easy. I can see a soft PB boolit also getting deformed into it if pressure is applied.
I make my sprue cutters super sharp and cut with a lot of little taps down a little towards the mold top. I never get anything sticking up. The worst I get is a little break out now and then when I cut too soon but that doesn't hurt anything.
I looked at all of my boolits with hard checks and none of the bases were real flat so I ran them all back through and now they look 100% better. Might be a reason for flyers.
I just checked all of my RCBS dies and they are all flat, so it must be a Lyman die in the sizer. Anyway, I like the bases now.
It also tightened the checks that I could feel movement on.

[floodgate]

I believe the main reason for the slightly concave "I" ejector punches was to provide a seal around the outer edge of the Boolit base, to prevent lube from working its way underbeneath the base - as Firebird and lurch state, this is in case of irregular sprue cutoffs, etc.

floodgate

[Nueces]

Years ago, some called for center-drilling ejector pins to provide a place for leaked bullet lube to accumulate without causing misalignment of the slugs. Stillwell Tool & Die offers this service, but I think his purpose is for the peripheral contact mentioned above.

Mark

[45 2.1]

Center drilling and rebateing the ejector pin has been talked about by Buckshot and Starmetal several times. Buckshot furnishes this on his sizing dies he makes.

[Bullshop]

Yes many of my older sizers have the punch this way. I use the concave end for lubing PB as it hase the base edge of the boolit sitting on the edge of the punch which seems to help the bases size more evenly. Now if you flip the punch over the reverse end should have a bevel on the outside edge. I use this end for lubing GC boolits. It seats the check flat and square. I am not so sure that they are still made this way but all my older sizers are this way. Come to think of it all my sizers are getting perty old, PRAISE GOD!
BIC/BS

[44man]

I can see an advantage to a hole for lube, I just wipe mine out all the time. I never get more then a thin film on the punch that wipes right off. Then again, I use soft lubes. It was an eye opener to see the gas check form to the depression after annealing. That just can't be good!
I put the sizer away last time without relieving the pressure, had a nice curl coming out.