go - nogo primer pocket pressure gauges

[ricka0]

Altho Case Head expansion (CHE) has been considered the best approach to measure excessive pressure - The physicist/statistician Denton Branwell has demonstrated that CHE cannot be used to measure over pressure. ( Even with my exceptional Mitutoyo .0001 blade Mike )

On my RUM brass, the primer pocket radius grows about 3x as much as the Case Head - so primer pocket radius is a more sensitive indicator. (it's probably also more uniform)

Suppose I take my preped (uniform the primer radius) brass and have a machinist make me some <font color="brown">go, go with force /ubbthreads/images/graemlins/cool.gif , no-go gauges </font> to slip into the primer pocket. I would have a fast way to measure primer pocket expansion.

I would like to use this approach in conjunction with the RSI rsi pressure trace system. (also using factory ammo as a reality check).

When I get a Allen uber Mag, I won't have the luxury of factory ammo.
comments, suggestions, idea please.

 

[Sasquatch]

i don't really see why that wouldn't work, but you would have to give the machinist the exact diminsions you are willing to have for your go, no-go. I would recommend you find a very seasoned machinist for the task as well. you are talking about tolerances close to +/- .0001 on a manual lathe.

 

[LB]

Well, you better make up your mind on your favorite brand of primer because they are not the same. No-go, on one, can be a perfect fit on another.

Good hunting. LB

 

[ricka0]

What about using a scale to measure bolt stiffness? I could measure primer diameter, CHE and bolt stiffness and see how well they agree with my RSI pressure traces.

 

[Tailgunner]

If you want to measure the pocket diameter, and changes there in, get a few "Plug Gauges" (the class X ones are NIST tracable), there available in increments of .0001 (tolerance of -0.00000/+.00004 for go type, -.00004/+0.00000 for No-Go types). Or you can get a set of 13 (-.0012 to +.0012) from nominal (select a nominal that is between your "go" and "no-go" numbers. A 13pc set will cost you $100, singles run about $15ea, from McMaster-Carr.

 

[ricka0]

Thanks. Here is their page. Plug Gauges

 

[LB]

?