does anybody have experience with this Nor-Cal Precision Tactical Vent System & Flash Hider
http://www.norcalprecision.com...andbreakoptions.html

No experience with them but in looking over their web site I found the statement of

"All machining on this rifle is held to a maximum of .0002 inches TIR. (TIR = Total Indicator Runout. TIR is the maximum allowable variance from the specified dimension over the whole circumference of any part.)"

Being a machinist tool and die maker I find that statement a little on the boastful side.
If every dimension on the action was held to that tolerance the action alone would cost $10K
So that sends up a red flag with me

Hmmm, .0002 is only .0001 off center or off dimension. I'm surprised that anyone can hold that type of tolerance in a lathe or mill. We always used grinders for that kind of tolerance. You can use a .0001 indicator to set up your work, but that doesn't mean that that's the tolerance you're going to get on the finished parts. But at least he's trying to do the best he can and his work probably shows that.

I'll have to agree with kcstott and clowdis. It is like Clay Spencer claiming he is holding .00005 when chambering. I doubt they have enough environmental control or expertise to do it.
Butch

Just an FYI There are lathes and mills built to hold such a tolerance But they are all very high end CNC stuff.
The company I use to work for had a lathe that could hold +- .00001" Ten Millionths In location and repeatability As per the manufactures claim Keep in mind we had no way to verify if it was anywhere close but the machine specs said accuracy and repeatability greater then +-.00001" and the control had ten millionths resolution. BTW it could only swing a 6" part 9" long it was basically a CNC screw machine
But yes Grinding is by far the only feasible way to hold those kind of tolerances And It's hard to hold +- .0001" let alone .00005"
Stop grinding and come back in an hour and you have to start all over again if the ambient temp changed

my question was aimed at the flash hider not the rifle(no pun in tended)