For a 20 Tactical reamer (20 caliber based on the 223) how much smaller does the resizing die reamer have to be from the actual case dimensions? Anyone know or suggest where I can look?

Thanks,

Mark

[ 10-11-2003, 22:28: Message edited by: MarkWhite ]

The smaller the case (think 223 vs 300 Win Mag) the less the diference is. Maybe 0.003 for a 223 based cartridge and 0.005 for a 300 Win Mag. Talk with Dave Kiff at Pacific Tool, he has all the numbers. Remember the resizing is gradual, we are not trying to resize the thick base at the case head, just the neck and a portion of the case below the shoulder.

Big cases need more, and the lever gun cartridges need more still. A lot depends on how tight the chamber is at the neck and the shoulder area.

Instead of a resize die, make a neck size die with removable neck size bushings. You can use the chamber reamer for this. For 30 cal. and under, I use the 1/2" diameter Redding bushings. Above 30 cal to 458 I make 5/8" diameter bushings and the neck size die is bored for this size.

Advantage of the neck die is you can just change bushings to give diferent neck tension on the bullets, one of the tricks used in tuning a benchrest rifle.

You can buy neck bushing type die blanks from Newland. Beautiful but expensive, about $50 each. Or you can make die blanks from old barrrel stubs, or 4140 bar stock. 4140 is easy to heat treat. Seat die does not need to be heat treated. And, neck size bushing type die does not need to be heat treated, only the bushing needs to be hard. I have made neck size bushing type dies from aluminum, but prefer steel.

Making case form dies gets interesting, sometimes you need several stages to prevent collasping of the case.

Mr Ricks,

Actually, I was planning on making a neck sizing die to begin with. The 20 Tactical is just the 223 necked to 20 caliber, with a 30 degree shoulder.

I already have 223 dies, so the sizer for that can be used to size the base. What I was thinking about was making a reamer for the neck and shoulder that I would use as the follow up neck size die. I am still thinking about how I want to go about this, I have access to a CNC lathe which would make this a piece of cake to do, but my little workshop lathe is a 1904 model bench top job, and it would be challenging to see if I could fabricate everything on that! I'm thinking about using a 7/8 bolt and using 2 reamers, one for the shoulder and one for the neck. I was thinking about then case hardening the die, is it will be used for forming too.

Does this sound like a practical and not too crazy idea? And yeah I know it would be simpler to just order the dies from CH4D for $69, I could get a job bagging groceries and be time and money ahead when all is said and the work done, but that's not the point. <G>

Mark