Pure Lead or With Antimony

[WayneShaw]

What advantage does a small percent of antimony give in a core? I've read 1/2% to 1% is used, but what is the reason?

Searching here, one reason stated was to reduce the cored jacket from sticking on the punch. This makes sense. There is a fine line, no pun intended, between a punch too big that scrapes the jacket, and a punch that has clearance. Clearance means some lead squeezing by the punch. Pure lead flows easy, and it doesn't take long to get a bit of lead buildup on the punch then the core jacket sticks on the punch. With a little harder alloy, maybe you can get the pressure to fill the core and not have the issue of bleed by.

[Mntngoat]

for harder cores

[WayneShaw]

Well, yeah......

[reed1911]

I would call it swager preference. I use pure lead. I don't mind a little bleed by, I never get lead stuck to my punch though. That is the only thing that confuses me on your post. Of course there is a fine line of a little bleed (small amount up the walls) vs. too much (bleeds all the way up and or over the edge of the jacket). I have a whole line of punches though so regardless of the jacket ID I have one that will fit. Of course I use 1 or 2 the most for each caliber and the other linger until needed for a project.

[Al Nyhus]

Hi Wayne.

I used both .5% and 1% antimony cores in my .30's with my preference being 1%. With the proper core seating punch, both would produce a perfectly concentric bleed by ring of .005-.006 with no core flashing up the walls.

Core build up on the punch(es) was minimal with both the .5% and 1%....the 1% was noticeably less, however. A couple of swipes with some 0000 steel wool is all it took to clean the punch.

When I made my own cores, 1% was my preference. When I started getting them from Charlie Hood, he only did the .5% cores, so that's where I ended up. I'd tested my own cores with .5% and 1% so I knew there was no difference in accuracy so making the switch to Charlie's cores was an easy transition.

I did some 2% cores and they shot great, also. The core seating process with a manual core seater requires more effort depending on your core seating press, etc, etc. Randy Robinett's air-over core seater sure made me smile when I used it.

[WayneShaw]

Thanks Al. Going to send you a PM.