.223 go gage for 6mm TCU?

[dcalloway]

Can I use a .223 go gage to set the headspace for a 6mm TCU? (.223 necked up to 6mm)
Thanks, Dave

 

[Preacher]

No reason why not that I can think of, as long as the parent case length to the shoulder has not changed.......

 

[Dan877]

If it's a true TCU then no, you can't use a .223 gage for it. The TCU body is longer with a very short shoulder and longer neck.

6mm TCU:
Base to shoulder: 1.455
Base to neck: 1.519
Shoulder Angle: 40 degrees
OAL: 1.750

223:
Base to shoulder: 1.438
Base to neck: 1.557
Shoulder Angle: 23 degrees
OAL: 1.760


If it's just a 6x45 (a.k.a. 6mm-223) then probably would work.

 

[KMart]

Here is a link to the PT&G gauge interchangability chart. The TCU family has its own gauges and is listed at the top

http://www.pacifictoolandgauge.com/pdf/headspace_gauge_interchangeabilty_chart_12_15_08.pdf

 

[wapiti25]

Are you doing the chambering? If so I would use the Go-guage as the N-Go and keep the chamber short so the brass is held very tight against the breech. If you are going to use NEW factory brass you should use it as your gauge. New brass is shorter than the std Go-guage. It may work, the 6mm TCU has the 40 or 45 degree shoulder. If you are going to form from 223 brass you need the 223 shoulder to fit against the shoulder of the TCU chamber which will be at the neck shoulder junction so you don't streach the cases. I used to fireform off the shoulder of 223 brass to form 7mm TCU with no problems. I used fired brass which is longer than new factory depending on the chambers where it had been fired by a few thousandths of an inch. The brass needs to be held tight (some crush) in the chamber when you fire form. The brass I was fireing was fired 223 necked to 7mm so I formed the shoulder to fit the TCU chamber. I hope this helps.