Now Southwest Product's "Pressure Trace" device is being delivered, I wonder if you could post first test impressions.

I write this because I happened to find this thread
http://www.nookhill.com/cgi-bin/ubbcgi/ultimatebb.cgi?ubb=get_topic;f=6;t=002164

where Denton and Dr.Howell are engaged in a fierce discussion about principles - especially Powley/Kolbe's recoil based system.
This leads me to ask if someone can report about Dr.Kolbe's pressure device.

From Makalu's French site I learn that he owns both systems - he is imho mostly competent to compare.

Well, I just received the pressure trace. I tested it on a hydraulic pipe, worked fine.

Kolbe works very well with my AR15, but gives only the max pressure. For one of my 308 rifles the pressure reading is much to low � I think it is because of an alu-mounting base.

I think you cannot mount the pressure trace on all guns, except if you like to mount them on the barrel well before the chamber, but this gives less accuracy.

Kolbe is very easy to calibrate and seems to work more or less. Pressure trace gives you far more information, but is not always so easy to mount and to calibrate.

If I have some time, I will make a small comparison next Saturday and if everything works well a big one in August at Nobel Sport.

Regards
Makalu

Makalu...

I'd be very interested in the details of your hydraulic test. I haven't figured out how to conveniently do that.

Denton,

the hydraulic pipe test was just to show in a quick way if the device works well.

We clued a standard strain gage (not form SW) on a fin hydraulic pipe (pressure of around 200 bar) and entered a much thicker pipe in the program (so you can simulate the same strain as with a barrel and a higher presser), you can calculate what you need, but because of the short reading and the turning up time of the machine it will not be that accurate.

We switched on the machine and well the short reading started. We had to but the trigger factor lower than 5 that it worked, but was a good and clear reading.

We did it because the people in my laboratory where interested to see how it works and as I need them for strain gage supply, we just did it.

Denton, I�m going to write an article about pressure trace, Oehler 43, Kolbe, Quick Load and piezo for a German Magazine, a friend of mine will do the same for a French magazine. Jim Ristow told me that you wrote an article for a hunting magazine in the US, which I will not find in Europe (I have only precision shooting). Could you send me a copy of this article, maybe it will inspire me a little pit.

Thanks very much

Makalu

Varmint Hunter published one in July, and is publishing another in September. I'll send you both.

Interesting solution, using an existing hydraulic pipe. I was trying to figure out how you had connected a rifle up to a hydraulic system, and given it a calibrated pressure pulse.

Denton,

thanks very much for the mail you sent me.

I think this is a good idea, with hydraulic presser in the gun. I think we could build a cartridge made of steel with the chamber dimension and connect this with a hydraulic pipe. You pump up a hydraulic reservoir to un certain presser and just open the valve to bring to presser in to the hydraulic ammunition. With a monometer on the second pipe, which goes in the cartridge you can see the presser in the round after elastically expensing. I don't know if it works fast enough, but hydraulic is very fast.

Is just an idea I don't know if it works, but way not?

Regards
Makalu