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Discussion Starter · #1 ·
One of my R/C rifles passed the "no go" guage test but it would not close on a "go" guage. Any suggestions? Thanks in advance.
 

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Give the chamber and barrel a good cleaning, I use a fiber 20 gauge shotgun bore-brush to clean the chamber on my Mausers, then check it again.
I usually just check my rifles with a field gauge and go with it.
 

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Who made your gages? Are they all from the same maker? Do they have a 19° or 20°48' shoulder angle? Your gages may made out of spec. I bought a set of gages for a 7.65x53mm Argentine and they were all about .020" too long. The shoulder angle was off also.
 

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Discussion Starter · #4 ·
Who made your gages? Are they all from the same maker? Do they have a 19° or 20°48' shoulder angle? Your gages may made out of spec. I bought a set of gages for a 7.65x53mm Argentine and they were all about .020" too long. The shoulder angle was off also.
Yes, same company made both gages. Forster brand. I'll start with the chamber/barrel scrubbing. Thank you, Gents.
 

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Have you tried to chamber a cartridge? Try the go gauge in another rifle. Does it also fail to close? You may have a gauge that is out of spec.

Forster sells two different sets of 8mm Mauser headspace gauges; one set with the current SAAMI 19° shoulder angle and one set with the obsolete SAAMI 20° 48' shoulder angle. Indications are SAAMI changed the shoulder angle in 1980. You should use the Forster 19° set that is closest to the original German chamber milspec.
 

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Who made your gages? Are they all from the same maker? Do they have a 19° or 20°48' shoulder angle? Your gages may made out of spec. I bought a set of gages for a 7.65x53mm Argentine and they were all about .020" too long. The shoulder angle was off also.
Please, what brand were they and where did you buy them. Many of us from time to time do indeed buy these gauges and the last thing we need is to waste our hard urned money on out of spec trash gauges. Good gauges are a very valuable and worth while tool to have.
 

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Please, what brand were they and where did you buy them. Many of us from time to time do indeed buy these gauges and the last thing we need is to waste our hard urned money on out of spec trash gauges. Good gauges are a very valuable and worth while tool to have.
Pacific Tool & Gauge, Inc. made the 7.65x53mm Argentine headspace gages that were too long. PTG used a length of 46.74mm (1.840") from a shoulder datum of 9.53mm (.375") for the go gauge; 46.86mm (1.845") for the no-go gauge and 46.99mm (1.850") for the field gauge. The only chamber drawing they had was a CIP with revision dated 99-04-20. The CIP chamber length from the 9.53mm datum was 46.15mm (1.817"); a go gauge difference of .59mm or .023". Original German barrel drawings indicate a 46.21mm (1.819") chamber length from the 9.53mm datum; a go gauge difference of .53mm or .021". Also, the chamber shoulder angle was off by more than 4' of angle. Like another gauge company, Clymer, they had several different gauge versions with different gauge lengths (7.65x53 Argentina/Belgian which they indicated were SAAMI specs and 7.65x53 Argentina CIP standard) for the same chamber. WTF. The 7.65mm Argentine is a problematic cartridge. SAAMI discontinued the spec for that chamber. CIP has a 7.65mm standard, but it varies from the original German milspec. Once I get some more info, I'm going to have PTG redo the 7.65mm gauges to original German milspec.

Forster makes gauges to SAAMI specs. The current SAAMI 8mm Mauser chamber spec does not match the original German WWII era chamber spec. Also, there is .006" difference between a Forster go and no-go gauge. All the German barrel drawings I've seen do not have a tolerance for the length of the chamber from the shoulder datum to the bolt face. The Germans could hold .01mm. The go and no-go gauges are used to fit the barrel. I think the Forster gauges are too sloppy for that task. I think the Forster no-go gauge should be used as a field gauge.
 

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tjg79...I just returned a set of 7.65 Arge gauges to Pacific. GO, NO-GO & FIELD all appear to be too long. I mailed them back along with a copy of your 2 posts about the 7.65 problem.

Wondering what happened with your set and was the problem corrected.
 
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