Go/no-go

I recently ordered a finishing reamer from Big Horn Sales in B.C. - he asked if I needed gauges - said I had a set made by JGS - he says they make "good" gauges - not sure what that means - they are in "spec" or they are not? They are made of hardened steel or they are not? There is a set of GO, NOGO and FIELD gauges here for 303 British - were made by a CGN guy - just the flange depth and diameter is important on those - the body is irrelevant - actually, "body of case" does not exist on these.

You can save yourself a few bucks if you are at all handy - get a GO gauge only - then go to Canadian Tire or NAPA and get a feeler gauge set - punch or cut out discs from feeler gauge leaves of various thicknesses - put dab of grease on bolt face - "stick" that disc to bolt face and use the GO gauge - for many cartridges a .004" shim with a GO gauge is same as a NOGO gauge. Might help to refer to SAAMI drawings - not all cartridges the same between GO and FIELD. Also, be aware that not all countries use same dimensions - SAAMI versus Sweden for 6.5x55, for example - Swede Regimental gauges were LONGER than SAAMI spec. I have no clue if you intend to "check" an existing rifle, or to install a new barrel. Seems to be desirable to install very close to "GO" - you want the bolt to close on "GO", but not much more, if you are installing a barrel - becomes "hell to pay" if you get a GO and NOGO mixed up on workbench when installing a barrel.
 
Brownells will tell you if anything they sell is controlled for export.
Doubt that gauges would be a problem.
 
A headspace gauge for a rimless cartridge will gauge the distance from the bolt face to a datum line on the shoulder angle. In the case of the 6mm BR (Norma), for instance, that datum line is the line at which the shoulder angle measures .3750" in diameter. This measurement (minimum) is 1.4953". Now, one could make a gauge with a contact diameter of .3750 and a length of 1.4953" and that would work fine, but with a sharp edge, it would be susceptible to wear or damage. So it is, manufacturers of reamers and gauges grind the contact area at the appropriate shoulder angle. This works out great; providing the gauge and the reamer both possess precisely the same angle. If the angles do not coincide, the gauge will contact somewhere other than the specified datum line, and the distance will be wrong. Now, this difference is likely to be miniscule, but it is different, nonetheless. This is why some will say you should have reamers and gauges from the same manufacturer. I guess they are assuming the reamers and gauges are ground on the same machine, with the same set-up, by the same operator; probably not.
I don't like to even have a no-go gauge in the shop. I can measure headspace with a go gauge and shims. If I was going to set up a barrel with a nut, I would use a "go" gauge and a layer of Scotch tape.
 
I have Manson Precision Gauges, Clymer Gauges and Pacific Tool And Gauge stuff. As Potashminer said "they are or they aren't" An if a manufacturer made something that wasn't in spec something tells me they would have a bad time after a few gunsmiths had issues.

They all work as intended. I got some through Big Horn Sales, Some used on CGN and some directly from the manufacturer. I know that Manson and PTG will both ship to your door so long as the order is under a certain amount (I believe Manson was 500$ PTG I am not sure but then sent me a reamer and gauges no issue)

I would start on the forums then check with a few shops then head straight to the manufacturer if you end up having to order.

B
 
I "got by" using Go gauges and shims for over 50 years... no go and field gauges are a waste of money as far as I was concerned.
 
^^^This^^^
Bolt closes on the Go Gauge but wont close on the Go Gauge with one layer of scotch tape on the back of the gauge.
 
Thank for your advices, its helpful.
I never did it yet...I’ll start with a go gauge and see if it’s ok.
I just hope I will keep all my fingers lol!

Thanks!
 
I much prefer a go gauge... set so it closes easily on the go gauge, yet stops firmly when a piece of tape is added...
 
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