.308 Go and No-Go are both No-Go on RPR

[Gadkinsj]

I am planning on installing a new Barrel in my .308 RPR. I picked up some tools including a go Gauge and a No-go Gauge. I Pulled off the handguard and trigger guard and decided to check a couple snap caps before I proceeded. 1 operates properly and 1 did not feed due to interference.

I moved on to try my gauges and I found that both my Go-Gauge and my No Go gauge are not-going (newly purchased off of Amazon from a supposedly reputable maker.) When measuring the gauges with a Mic (yes Mic not calipers) they are less than .001 difference in overall length. They have a relief cut for firing pin and I did not remove any of the Bolt pieces.
I have not touched the Barrel yet to affect the headspacing. Rifle is less than a month old. it has run 100 or so rounds through it with no Issues with the action or firing of the weapon. The Brass all looks normal coming out although I have not measured any of it.

Anybody wanna help me understand what I'm missing? How can I verify my Gauges are not mis-marked?
Thank you

Edit:
Guages are:
Manson HS Gauge 513-100-261 (no go)
Manson HS Gauge 513-100-260 (go)

 

[Edd]

I am planning on installing a new Barrel in my .308 RPR. I picked up some tools including a go Gauge and a No-go Gauge. I Pulled off the handguard and trigger guard and decided to check a couple snap caps before I proceeded. 1 operates properly and 1 did not feed due to interference.

I moved on to try my gauges and I found that both my Go-Gauge and my No Go gauge are not-going (newly purchased off of Amazon from a supposedly reputable maker.) When measuring the gauges with a Mic (yes Mic not calipers) they are less than .001 difference in overall length. They have a relief cut for firing pin and I did not remove any of the Bolt pieces.
I have not touched the Barrel yet to affect the headspacing. Rifle is less than a month old. it has run 100 or so rounds through it with no Issues with the action or firing of the weapon. The Brass all looks normal coming out although I have not measured any of it.

Anybody wanna help me understand what I'm missing? How can I verify my Gauges are not mis-marked?
Thank you

You have to measure from the base to a spot on the shoulder taper. If you are doing that and finding less than .001" difference, the gauges are not marked correctly.

 

[Gadkinsj]

Thank you. That sounds like a tricky measurement to get. Got any tips for me?

 

[Edd]

Thank you. That sounds like a tricky measurement to get. Got any tips for me?

If you only have a mic to use for measuring, you are going to need a cap of some kind with one open end and one closed end to fit over the gauge. If you have a caliper, you can use a tube.

Hornady sells the parts to use with a caliper. You can google that for information.

 

[Stumpy1]

My recollection, and it could be wrong, is that the datum point on a .308 go gauge (or cartridge) is 0.400 in diameter on the shoulder.

SO -you could use a sized .40 smith and wesson cartridge (open side) on the shoulder of the gauge and measure from the base of the gauge to the base of the .40 cal cartridge. Compare the two measurements and see if they are different. (picture stolen from the internet)



Hope this helps,

Frank

 

[Edd]

My recollection, and it could be wrong, is that the datum point on a .308 go gauge (or cartridge) is 0.400 in diameter on the shoulder.

SO -you could use a sized .40 smith and wesson cartridge (open side) on the shoulder of the gauge and measure from the base of the gauge to the base of the .40 cal cartridge. Compare the two measurements and see if they are different. (picture stolen from the internet)


Hope this helps,

Frank

You don't have to measure at any specific diameter for comparison. Anywhere on the shoulder will work as long as you measure both gauges the same way.

 

[Coyotefurharvester]

Over all length of the gages ?

 

[akajun]

First, you chamber and bolt and receiver must be CLEAN!!! to get the proper measurement. And while tight headspace may be an issue if your loading hot rounds, If your just shooting factory rounds or loading from brass fired only in that rifle Youll probably be ok.
another thing is sometimes a makers chamber /reamer drawing is not the same as the gauges your using. Manson makes good stuff, the best, but I doubt ruger is using his reamers as Im sure they have a tool and die shop in house.
Using the same box of factory ammo.Get a Hornady Shoulder bump gauge and measure a few fired cases from your rifle. Then measure a few from another known good bolt rifle in 308 and see what the difference is. if its within .001 or two Id leave it.

 

[gunsandgunsmithing]

If you are able to size your fired brass to chamber, it's unlikely that your go guage is marked wrong, but it's possible. What I've found to be true over the years is that, with very few exceptions, a barrel chambered to zero clearance on a go gauge may not get sized enough by factory dies. Nevertheless, start by properly measuring both gauges to verify a difference of about .004 between the go and no go. Then go from there. The only thing certain here is that you can't measure oal length of the gauges and get a number that means anything. The 40 cal case trick will work but before discounting a precision made gauge as being bad, I think it'd be a good idea to actually use something made for the job. I'd think an optical comparator would be best but since you're after a comparative number rather than a specific measurement, the Hornady tool and a set of calipers should suffice.

 

[wkdickinson]

I am planning on installing a new Barrel in my .308 RPR. I picked up some tools including a go Gauge and a No-go Gauge. I Pulled off the handguard and trigger guard and decided to check a couple snap caps before I proceeded. 1 operates properly and 1 did not feed due to interference.

I moved on to try my gauges and I found that both my Go-Gauge and my No Go gauge are not-going (newly purchased off of Amazon from a supposedly reputable maker.) When measuring the gauges with a Mic (yes Mic not calipers) they are less than .001 difference in overall length. They have a relief cut for firing pin and I did not remove any of the Bolt pieces.
I have not touched the Barrel yet to affect the headspacing. Rifle is less than a month old. it has run 100 or so rounds through it with no Issues with the action or firing of the weapon. The Brass all looks normal coming out although I have not measured any of it.

Anybody wanna help me understand what I'm missing? How can I verify my Gauges are not mis-marked?
Thank you

Edit:
Guages are:
Manson HS Gauge 513-100-261 (no go)
Manson HS Gauge 513-100-260 (go)

I have Manson 308 Win "GO" and "NO GO" gauges. The difference in length, measured using an RCBS Precision Mic is 0.008".

 

[tobnpr]

Your ammo was fine, no issues feeding/extracting.
Forget the snap caps. They're obviously a bit out-of-spec, I can guarantee they're not manufactured to the tolerances of ammunition, much less hardened and ground gauges.

I'm sure DM's gauges are fine. You need a comparator as mentioned to, well- compare the two gauges if you feel the need to do so. It's the length from casehead to a datum point on the shoulder that need to be measured- has nothing at all to do with the overall length of the gauges.

It's a bit unusual for factory ammo to chamber but not a go-gauge, but not unheard of.
You really should strip the bolt when using gauges. No FP, springs/ejectors that cause resistance.
You need to "feel" what's going on.

Sounds like the barrel nut was tightened with headspace a bit short. Don't see how it would affect anything with the replacement.

 

[LVLAaron]

Sounds like the barrel nut was tightened with headspace a bit short.

Easy to do with barrel nut configurations. Factory ammo is usually on the short side.

Ultiamtely, OP needs a headspace comparator.