Author Topic: crush fit? (Read 495 times)

singleshotbuff · « **on:** April 19, 2003, 11:58:12 AM »

Hello guys,

I'm new here. Been reading the forums for awhile, but this is my first post.

I have a question about caseforming. I have a 7x57mm Mauser, and thought I'd try to form some cases from 30/06 brass as I have tons of it around. I plan to use this formed brass for cast bullets only, to save my factory brass and to keep brass segregated. I annealed the 30/06 cases, partially necked them to 7mm, and trimmed them to just over final length. Then I lubed them and ran them into a 7X57mm F/L sizing die (turning them 1/3 turn and then going further), then trimmed them to final length. They formed ok, but as I tried to chamber them, there was a bit of resistance. I compared my formed case to a factory case and found that the shoulder was formed slightly forward. If I fire these with a starting cast load, will it be safe? Will the case then form to the chamber? I'd appreciate any help as I'd like to shoot these case tomorrow.

SSB

jhm · « **Reply #1 on:** April 19, 2003, 02:14:19 PM »

singleshotbuff: Is it not posible to adjust the die down anymore to set the shoulder back closer to where you may need it? I like the brass to flow into the chamber when fire formed myself, but I am just one of many and others may be alot more up on it than I am.

JIM

singleshotbuff · « **Reply #2 on:** April 19, 2003, 02:19:50 PM »

Jim,

Thanks for the reply. I have the die screwed down until it firmly contacts the shellholder. I've never tried caseforming before, so I'm not sure why the shoulder is forward. Brass elacsticity maybe? The shoulder is also a bit rounded instead of sharp like a fireformed case. I think the shoulder is just formed at a wrong angle instead of too long.

SSB

Geno · « **Reply #3 on:** April 19, 2003, 02:40:46 PM »

That after shortening the case from 2.494" to 2.235" (about 1/4") that what you have is a much thicker neck. Then once sized and you stuff a 7mm bullet in there, you now have a case to large for your chamber. Take and Mic the neck dimension with a bullet seated in it. My manuals say that .321" should be your measurement. If you have more, you'll need to inside neck ream those cases if you intend to use them. The shoulders shouls square up and take care of themselves when fire formed if your headspacing is ok. If this is the case, I wouldnt shoot them, pressures will rise very quickly.

jhm · « **Reply #4 on:** April 19, 2003, 04:08:40 PM »

Singleshotbuff: Another item I forget to mention when you are reforming brass from one caliber to another be sure to lube the inside of the necks real good so when the expander ball is coming out of the brass it has less resistance as that will cause the brass to STREACTH and you dont want that as geno stated you are making the neck area brass thicker when you are reducing in caliber and that thicker neck will cause the expander ball to pull the necks out also, let us know how it turns out we have all been there and suffered these problems.

JIM