Go-no go gauge dimensions
- Thread starter Dirtrax
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cohunt
Well-Known Member
Go should be saami minimum spec for your chamber, field gauge should be .010" longer (saami max spec) the "no-go specs will vary my manufacture but around .004-.006" longer than go gauge . Ther are still manufacturing tolerances to consider but generally these are kept very tight on gauges and reamers. The actual number/amount really is moot just use the gauges correctly and there really is no need to know the numbers for most people. If you want to know exactly what size your chamber is, then a chamber cast is the way to go.
This assumes it's a saami spec chamber--- you can always check with the gauge manufacture for the gauge specs. If it's a "wildcat" then you should definately confirm specs.
You can always go to the saami website and look up saami chamber specs for min/max dimensions.
If you need a gauge to check or set headspace they are available to rent fairly inexpensive.
This assumes it's a saami spec chamber--- you can always check with the gauge manufacture for the gauge specs. If it's a "wildcat" then you should definately confirm specs.
You can always go to the saami website and look up saami chamber specs for min/max dimensions.
If you need a gauge to check or set headspace they are available to rent fairly inexpensive.
shortgrass
Well-Known Member
cohunt is exactly right in his explanation. For an exact head space measurement I've always used the GO and added brass or steel shim stock to the base of the gauge until I can feel it when I close the bolt.
That's exactly what I have been doing. Sometimes I just over-think things and I want to be sure I'm doing the right thing. I read in another post where Cohunt mentioned that Manson no-go gauges are .006" longer than the go gauges. I'm using a .007" shim and adjusting headspace (remage) until it will only close with some effort applied. All seems well. My ADG brass seems to take 3-4 firings to get to length at the datum unlike the WW brass I was using. I just thought I'd throw it out there to confirm/deny my method. I don't want to use the belt for headspace.
shortgrass
Well-Known Member
So, you are trying to make the body of the case longer by fire forming? On belted magnum hunting chambers I stay between Go and Go plus .003" and let the forward portion of the case body expand to the chamber when fired. I have been using Go to Go plus .003" for nearly 30 years and had no complaints. Re-sizing hasn't presented any problems as I always recommend to adjust to enough 'bump' for easy chambering. It's a hunting rifle and needs to chamber the 2nd round easily for a follow-up, if needed (I never get to shoot at 'stupid' animals where I might get a 3rd shot if I've screwed-up the first 2).
shortgrass
Well-Known Member
I can see adding .006" in body length adding nothing to the velocity of a magnum round. I can see adding .006" to a .473" head sized case adding nothing to velocity. The difference between GO and NO-GO is nothing more than the 'working tolerance' found in any 'machine' the works in a reliable manner. After a few firings the diameter just above the belt will interfere with 'easy' chambering,,, and the only 'fix' for that , that I know of, is the $120 collet die for magnums that Innovative Technologies makes.
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