reloaders chamber pressure gauge

[jbunny]

i have been thinking about a need for some way to measure chamber pressure at the range.
my needs are mainly for loww pressure cartridge use in antiques 38 spl and 455 webleys.
u can get the OEHLER chrono with the pressure transducer. to rich for my blood especialy when u have to go to texas for training. my first thought was to make a
pliers to make a small dimple in the brass and then stick a strip or small disc of aluminum or lead of a precise width or diam and messure the width with a lee precision
lead hardness tester microscope after fireing. i,m now thinking of the KISS PRICIPLE.
take a pair of cheap pliers grind, file one jaw the same inside radius as the brass
u are useing. the top jaw would be drilled through to accept little pins of differant
pointed profiles. these would mate up with mactching dimples in the lower jaw.
if u had 3 or 4 diff size of dimples in the brass. at low presser the bigger flater dimples
would be gone or smooth and each flat one would indicate a certain pressure. lyman lists the pressures for the 38 spl, just trial and error and recording the results. the human finger
is capable of feeling a 1/2 thou bump or imperfection.u get the drift.
thoughts or ideas?????

[handyman25]

i would think that you could have lots of variables, different brass thickness, different brass alloys, has the brass been work hardned etc. Also even if you have a dimple smooth out at what pressure? To me it would all be a big guess. But at least you are thinking, trying something new.

[a.squibload]

Maybe something like a plasti-gage strip on the outside of the case?
Might be tedious to get it chambered...

[Ernest]

In low pressure loads it makes sense to me. very ruff gauge but still usable . The late great Ken Waters did some what the same thing by carefully measuring cases with a micrometer.

It seems that you could calibrate by pulling a couple of factory loads. Put the dent in the case and shoot it and examine. Then put up your test load in a new dented case of the same make and shoot that. I would guess that you would notice when you went over factory pressure.

[jbunny]

hi list; the object of this crude pressure indicater is for my antiques. i want some thing to indicate in the 10,000 to 12,000 psi range. the lyman 46th edition has the pressure
as well as the velocity for the 38 spl. they have some loads that start at 7,000 psi.
by duplicateing the loads and with a chrono , it should be close. i hapen to have a few
38 spl antiques. i hope to start on this next week. cheers

[jbunny]

hi folks, this dimple pressure gauge is working. in this first pic, the dimple was a blunt
point. no change with the low pressure rnd. the edge of the dimple was flatened a bit with the full house load.

By mouich at 2012-02-05

in this pic i put 2 diff size dimples side by side. the right case was with the starting load
that is supposed to be 8,900 cup. the left case had the same size dimples and with a p+ load which is supposed to be 18,000 CUP, the dimples are gone. now the real work begins. will have to wait for warmer weather for range work with the chrono.
i,m suprised that nobody brought up the canulure in brass cases. they stay put in
some cases. YAHHHHHHH HOOOOOOOOOO
ps, i will be useing fresshly anealed cases for the calibration.

By mouich at 2012-02-05

[Ernest]

what a wonderful Idea!!