Measuring headspace / Reamer stop

Mat

Well-Known Member
Not to detract from Jager SA's thread... Thought I'd start a new one.

In case anyone is interested, I bored & threaded a ring 1.000" long, so to measure how much more to ream, it's a case of measuring the depth to the gauge and doing the sums...

20130327_214302_zps5baea676.jpg



Then made an adjustable reamer stop

20130327_214356_zpsdfe50c3b.jpg
 
Nice


allows you to chamber and headspace barrels correctly without pre fitting .


Useful if doing glued in BR actions or AI AW / AX models.....

I guess you cut the cylinder to the length of the action at the datum line of the bolt face...simple sleeve fit to the shoulder of the barrel and measure from there with go / no go and micrometer,,
 
Last edited:
You don't actually need to cut it to the length of your datum, which would change depending on action... Suppose your depth from action face to bolt face is 0.700" and your cylinder is 1.000", then when you screw it down and take a depth measurement off the headspace gauge, it needs to be at least 0.300", so it comes up short say 0.290" then you know you need to ream an extra 0.010".

I hadn't thought of glued in actions! I came to the conclusion that using feeler gauges was a bit coarse and trying to using the depth mic on the end of the headspace gauge was wobbly, so decided I needed a better solution.

Not seen anyone else do this, but I can't imagine it's a novel idea.
 
for the non engineers

does your threaded ring go on the barrel tenon and is that thing you are measuring a go/nogo gauge?
 
You don't actually need to cut it to the length of your datum, which would change depending on action... Suppose your depth from action face to bolt face is 0.700" and your cylinder is 1.000", then when you screw it down and take a depth measurement off the headspace gauge, it needs to be at least 0.300", so it comes up short say 0.290" then you know you need to ream an extra 0.010".

I hadn't thought of glued in actions! I came to the conclusion that using feeler gauges was a bit coarse and trying to using the depth mic on the end of the headspace gauge was wobbly, so decided I needed a better solution.

Not seen anyone else do this, but I can't imagine it's a novel idea.



Its not the first time ive seen this idea Mat, but it reminded me its something I could do with making as i'm rebarrelling an AX soon and as the actions glued to the chassis, I have to work out a way of measuring H/S ---- which, thanks to the memory jog, will be a little easier now..
 
Seen similar setups on BRC. As many of you will be aware you can purchase a micrometer version from D. Kiff at PTG.....

All that said I like it...I like it a lot!......looking forward to your next post on the subject.
Head space Micrometers.jpg
 
Back
Top