I thought someone may comment on what I find to be an odd piece of data. I recently completed my first .416 barreled action (Taylor) and cobbled a stock together enough to shoot. Worked perfectly. My question has to do with neck diameter.

The Clymer website, Cartridges of the World, most reloading sources and a book I have on cartridge conversion show the neck diameter of most .416 cases to be .445 inches. Number one, I was suspicious that the Clymer database was the same as most cartridge drawings, since they should have reamer specs, not cartridge. The .445 measurement seems awfully high for a .416 bullet. I have two .416 reamers, a removeable pilot Taylor reamer and a Clymer Neck and Throat reamer. Both these measure closer to .435 than .445. Loaded ammo made from WW .458 measures .432-.433 with no neck turning. If anything, you would think it would be slightly thick due to necking. After firing, it measures .436, which would indicate I got about .001 runout with my chambering.

What gives here? I would think that .335-.336 would be more normal for any .416 caliber. If this is true, how did all these .445 measurements slip into almost all the .416 references.

That is the case neck diamiter wich souds adout right .416 for the bullet plus about .014" for the brass on each side of the bullet. the case would run around .010 to.012 that leaves a little roum for the release of the bullet

A .436 neck on a .416 would require a case wall thickness of only .0085. with about .003 clearance for expansion. Thats awfully thin brass my friend! I measured some ww brass and its .013. thick With a .416 bullet that would be .442. Thus, a .445 chamber neck dimension makes total sense given that this is a DGR not a benchrest cartridge. I also just measured a loaded .416 Rigby cartridge and its .443 -Rob

[ 02-18-2003, 08:28: Message edited by: Robgunbuilder ]