How to use headspace gauges.

[maufic]

Hello,

I'm getting ready to assemble a rifle my self for the firts time. I'm using an ultimatum hmb action, which has a sako style extractor. I'll be installing a nut style barrel. I realize that I need to remove the ejector to ensure when checking headspace, but do I also need to remove the extractor? I have asked a few people and get mixed answers. Thank you in advance for any comments.

Moro

 

[Judd]

No, leave the extractor otherwise the go gauge will be a pain to get out of the chamber and the extractor doesn't push on the go gauge like a ejector does. Do pull the firing pin so it doesn't "cock" on the trigger.

How I would do it...put tape on the back of the go gauge that is .002 thick (think packing tape). Start screwing the barrel on the action...then "chamber" the go gauge (make certain the ejector is snapped over the brass case head) and tighten the barrel until it just gets tight (don't ape it or you'll go too far). Then tighten up the nut on that spot....then pull the go gauge and pull the tape off. Chamber the go gauge and the handle should fall freely at minimum it has to close and some like a slight drag on the bolt handle.

Then check the no go gauge (or you can put a piece of .004 thick painters tape on a go gauge, making it a no go) and make certain it doesn't close...most don't even want the bolt handle to fall over.

It's not hard, you can do it. The end result is the go has to close and it can't close on a no go....if you do that, it'll be fine.