Need Help with Headspacing 7mm Remington Magnum

I have had the barrel off my Savage 110. This is chambered in 7mm Rem Mag. I borrowed some headspace gauges from my local gunsmith. I set the headspace with the extractor removed. The bolt will close on the go gauge, it will not on the no go gauge.

My issue is this:
To check my work, I took a sized case to make sure it would chamber. No problem with the bolt closing on the case. I added two layers of scotch tape to make a no go gauge out of the sized case. To my surprise, the bolt closes easily on this as well. I checked the case with my RCBS Precision Mic (compared length of case with/without the tape) and the tape thickness is .004". I added two more pieces of tape, and the bolt still closed easily.

I have no really good way to measure the distance from the top of the belt to the bottom of the case, but tried to measure this using my caliper. The go gauge measured .220 and the no go gauge measured .224 (sammi spec). I measured several pieces of brass and they meaured .212 consistently.

My question is this - Do I leave the chamber set to sammi spec, or do i re-headspace using a piece of sized brass? It seems to me that .008" is a lot of excess space in the chamber from the bolt face to the belt.

Thanks in advance for your help.

Dennnis

The gauges are your standard. To me, a case is incomplete until it is fire formed to my chamber. Once you make those cases go boom, you can space off the shoulder and any gap will disappear. The way things have gone with quality control of cases lately, nothing surprises me.

Place the gauge in the breach. With the bolt closed, screw the barrel in until it stops, this is done lightly..then snug the barrel nut. You should only have about .0005 to .002 clearance on a belted magnum. Check with no gauge or your tape thing. It should close with ease without tape and should not close with tape.

Yea what he said, no seriously either headspace it of the belt or headspace it of the shoulder, do not try and compromise between the two. personally I would go off the belt and let the brass form itself to your chamber.

Dean

Brass is not held to nearly the standards that go/no-go gauges are. Use the go gauge as your spec. Only time you would use brass is if you had previously fired that brass in that rifle, then took the barrel off and wanted to set it back up to previous spec.