Pressure numbers from Hodgdons

[stimpylu32]

Did some looking for pressure numbers on the Hodgdon's web site for all the rounds that the H&R Handi rifles are chambered in , so here is what i have come up with so far .

500 S&W - 44,900 PSI

450 Marlin - 41,200 PSI

45/70 Trapdoor - 20,500 CUP
          Lever - 31,600 CUP

45 Long Colt -12,000 CUP

444 Marlin - 38,300 CUP

44 Mag - 35,100 CUP

38/55 - 25,500 CUP

35 Whelem - 45,600 CUP

357 Max - 46,900 CUP

357 Mag - 38,400 CUP

30/06 - 55,600 PSI

308 - 49,600 PSI

30/30 - 33,300 CUP

7.62X39 - 36,000 CUP

7mm/08 - 49,900 PSI

7x57 - 42,100 CUP

7x64 -

280 - 45,900 CUP

270 - 55,000 PSI

25/06 - 47,200 CUP

243 - 48,600 CUP

22-250 - 55,000 PSI

223 - 47,800 PSI

22 Hornet - 41,800 Cup

204 Ruger - 48,300 PSI

Now these numbers do mean something , but case head size and case head thrust must also be plugged into the factors of what kind of pressures will the handi take .

A work in progress .

stimpy

[quickdtoo]

  Umm Stimpy, you musta looked in the start data for the 500, max is  51900kpsi, trapdoor 45-70 is 28kcup, levergun 40kcup, dunno where you're getting the psi figures for the 45-70, but they only show cup.

A liitle FYI, although it's not easy to measure a sectioned case, the insider diameter of a Starline 45-70 case is ~.400, a Starline .500S&W case is ~.440".

To determine bolt thrust, you'll need to figure out the inside case head surface area.

Bolt Thrust
Bolt thrust is easy to calculate. Only two inputs are required. They are peak chamber pressure in PSI and as mentioned, the inside area of the case head that the gas pressure can work on. The formula then is:

THRUST=AREA*CPSI Where:

AREA=3.1416*(HS/2)^2

HS=the diameter of the inside of the case head. 
http://www.riflebarrels.com/articles/custom_actions/bolt_lug_strength.htm

Tim

[stimpylu32]

Tim

Yep , its starting data , about every week or two someone will ask about what kind of pressures will the handi take , so i did the looking . 

Thought that with starting pressures , the if it will take this why not this guy would be safer .  , Like i said its a work in progress .

And your right about the PSI / CUP on the 45/70 , i'll fix it , fat fingers and too many lines .  got the 450 data in the 45/70 line .

stimpy

[quickdtoo]

I think the recoil is a bigger issue than what the gun will take with any factory chambering, even if the frame/underlug will take the pounding, the shoulder/body abuse is the ultimate deciding factor for most of us.

Tim

[Smokin Joe]

Hey, Tim Stimpy, an easier Area formula is: D2  X .7854

Diameter squared times .7854







thanks Joe,

Tim

[McLernon]

Does anyone know the relationship between C.U.P. and peak pressure in psi?

Mc

[quickdtoo]

If there is such a thing, start readin...   http://www.shootingsoftware.com/ftp/psicuparticle2.pdf

Tim

[stimpylu32]

Tim

You got the body pounding part right , try putting 50 rounds of 450 Marlin down range in one afternoon , OUCH , or even some upper lever gun loads in the 45/70 .

A lot of people will think of the heavy hitters but what about the 204 , 22 Hornet and the 223 , these are rounds that work in the higher pressure range but with a much smaller surface area of case head .

stimpy

[quickdtoo]

That's why I bought a Lead Sled DFT!!!

Smaller surface area is good, much the same as less pressure is good, concerning Handis anyway. Now ya get to cut some brass up, looking forward to your final analysis after the cuttin and measurin!!

Tim

[canon6]

If you really want to get confused Google SAAMI pressures for some of the cartridges NEF chambers in the Handi, then consider that NEF would not chamber a cartridge that the legal types thought would put NEF in jeopardy.  Doug

[LaOtto222]

"That's why I bought a Lead Sled DFT!!! "

I have one too, look at the little picture to the left. Sure is nice for the big kickers.

[trotterlg]

Quick:  You usually know your stuff, but the case head thrust is dependent on the diameter of the chamber at the breach, the brass acts as a piston.  The pressure is distributed across the entire diameter of the cartridge, even the walls of the brass.  If this was not the case you could just build brass that tapers on the inside to just the size of the primer hole and have a very low thrust cartridge.  Unfortunately it does not work that way.  Larry

[quickdtoo]

I'm afraid Dan Llija disagrees with ya, I didn't make that up, it's quoted from his website which I provided.

Tim

http://www.riflebarrels.com/articles/custom_actions/bolt_lug_strength.htm

[stimpylu32]

That's why I bought a Lead Sled DFT!!!

Smaller surface area is good, much the same as less pressure is good, concerning Handis anyway. Now ya get to cut some brass up, looking forward to your final analysis after the cuttin and measurin!!

Tim

Ya , i have over 1/2 of those rounds here already , just need to start cutting and figgering . 

stimpy

[quickdtoo]

Any of em that ya need that I have(7x64), I'll donate to science!!!

Tim