Cartridge pressure?

supposedly the magnum primer use over standard types should create more pressure with same amount of powder? some state back off 1/2 gr when using magnums. using a 629 over 2 decades of a 44mag @ max loads the n frame should be gtg. i've shot probably 10k that way. not sure about the l frames in 44mag?

It actually depends on the powder being used with the mag VS standard primer thing. A fast easy burning powder like titegroup/bullesye/etc. will show no signs of increased pressure with a mag primer VS standard. Slow hard to ignite powders like hs-6/h11o/etc. will show higher pressures simply because of a better/more complete burning of the powder.
 
You know, seems like I'm hijacking my own thread. I still haven't found a comprehensive answer to my "is there a chamber pressure equation somewhere out there?" Jim Watson in post #3 here shows an interesting site but seems a little to high-techie for me personally.
No there is not. The only way to be certain of the chamber pressure of any given load is to test it in a test barrel that has a pressure sensor.
 
Storminorman!
Right as rain yet again. The way I see it there may be WAY too many variables involved for a simple equation.
And yes sir, moose sure are big suckers, wouldn't want to get stomped by one. Had an absolutely GIANT bull come sniffing in my camper window late one night a couple years ago when I was building my cabin up north. Seemed like it took him 10 minutes to walk past that window once he decided to leave.

BC38,
Does that max charge you found use magnum brass? Seems a little low. Reduced load for 44 mag maybe? And yessir I'm definitely going to back off a little with my charges. I DO think the gun can handle those 10 grains in special brass. I'm not convinced the pressure I may or may not be generating (difficult to predict without some type of math/physics equation) would be any more than a mid range 44 magnum load. But for sheer enjoyability of the round I am going to back off a little.

I guess I'm just a little perplexed that all these thousands of pressure numbers listed in hundreds of manuals don't offer any insight as to how these numbers were arrived at. Or maybe they do and I just haven't noticed it. I figure if these manuals PUBLISH this type of information then they have tested each and every load, in each and every caliber, with each and every bullet listed with some type of machine or measuring device. And if they haven't, that means the information they provide is pretty much just an informed guess. But informed how?

Maybe I should backwards engineer some of their numbers and create my own Cartridge pRessure Approximation apP. I could name it the C.R.A.P. equation and post it online somewhere.

Anywho, sorry for the blather.

Good morning all!
 
Storminorman!
Right as rain yet again. The way I see it there may be WAY too many variables involved for a simple equation.
And yes sir, moose sure are big suckers, wouldn't want to get stomped by one. Had an absolutely GIANT bull come sniffing in my camper window late one night a couple years ago when I was building my cabin up north. Seemed like it took him 10 minutes to walk past that window once he decided to leave.

BC38,
Does that max charge you found use magnum brass? Seems a little low. Reduced load for 44 mag maybe? And yessir I'm definitely going to back off a little with my charges. I DO think the gun can handle those 10 grains in special brass. I'm not convinced the pressure I may or may not be generating (difficult to predict without some type of math/physics equation) would be any more than a mid range 44 magnum load. But for sheer enjoyability of the round I am going to back off a little.

I guess I'm just a little perplexed that all these thousands of pressure numbers listed in hundreds of manuals don't offer any insight as to how these numbers were arrived at. Or maybe they do and I just haven't noticed it. I figure if these manuals PUBLISH this type of information then they have tested each and every load, in each and every caliber, with each and every bullet listed with some type of machine or measuring device. And if they haven't, that means the information they provide is pretty much just an informed guess. But informed how?

Maybe I should backwards engineer some of their numbers and create my own Cartridge pRessure Approximation apP. I could name it the C.R.A.P. equation and post it online somewhere.

Anywho, sorry for the blather.

Good morning all!
""""""I guess I'm just a little perplexed that all these thousands of pressure numbers listed in hundreds of manuals don't offer any insight as to how these numbers were arrived at."""""

Have you actually read the information in the manuals? All of them tell you up front how they arrived at their pressure data, usually test barrels, the type of sensors they use and length of those barrels. Many of the old manuals like Speer then give velocity data for specific guns.

The newest major manual on the market is the Nosler, first published in 2022. It lists barrels by brand and length. Each caliber they cite the pressures and how they got there.

There is no mystery, every manual tells you their process, and if you do not exceed their recipe you never have any risk whatsoever. Just read the entire manual and your questions and answers are there.

Besides, the only way to know the pressure in your gun is to test that gun, not some formula.

The 44 mag and 44 special are old and well documented calibers. There is a mountain of published safe data. The mag guns are overly powerful for casual shooting by most so there is an abundance of light loads or 44 Special or 44 Russian loads for shooting paper or generally just burning powder.

Unless you are actually needing the max power, everything works. The traditional 240 grain cast and 10 grains of Unique is barely a magnum, but will do anything you need to do on the trail or in town. I shoot it in my 29 ounces 44 mag, my model 29 and my Redhawk, it is pleasant. HS 6 is a decent powder, better than many. Just load it according to the manuals and forget about it. If recoil bothers you, load at the entry level.

You are overthinking this one, it is like the 38 special, except bigger. Nothing to see here. The 69 is nice size gun to carry BTW, same all most of those 44 five shooters. Enjoy.
 
Law-dog,
Thank you for the post and I agree with everything you say. 44 caliber rounds have been tested, toyed and tinkered with for what seems like forever. I understand and appreciate the testing, time and equipment necessary for us to be able to enjoy this beautiful caliber safely. And yes I KNOW I'm overthinking this one. Somehow this whole pressure thing, without math to back it up, got stuck in my craw so to speak. And yes sir I am enjoying the new to me 69. Wonderful revolver.
Thanks for putting up with my rambles.
Stay safe.
 
And yes I KNOW I'm overthinking this one. Somehow this whole pressure thing, without math to back it up, got stuck in my craw so to speak.

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Forrest r already gave you the answer to the question concerning pressure for that load (HS-6 @ 10 grains under Missouri bullets rnfp 240 grain cast) with more specificity than you'd get in the majority of reloading manual, of which few tell to you the expected pressure.

The 44 Special tables listed in Handloader #236 (not #246) have been published multiple times in various issues, in one form or another.

Your lighter bullet (240gr -vs- 255gr) will lessen the pressure even more below the 22K max listed.

I have the program QuickLoad (QL) that lets you calculate pressure but you need more specifics than you've given to perform such a calculation & even then the results need to be taken with a grain of salt.

I only use QL when I'm trying to develop loads for an obscure cartridge like the 356TSW or 10mm Magnum, which little data exists anywhere, or for a new wildcat cartridge like my 45WSM which no data exists for, but even then it's only used in conjunction with other data obtained from different calculations to arrive at a safe starting point.

Your load doesn't require this.

I too would suggest that you just use 44MAG cases instead of 44Spcl cases for your reduced loads in the M69 for multiple reasons.

Yes , you're overthinking this one. ;):)

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Handloader #236 article, Handloading 44 Special
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I like Power Pistol for my reduced loads in 44MAG cases. Expect velocity lose with the 2-3/4" bbl. compared to data for a longer bbl.
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+ (one word, three letters) WOW!

Great post, BD37!

Cheers!

P.S. If you can load 10.0 gr HS-6 with a 255gr Keith-style in 44 Special brass (as indicated above as a "second category" 22K psi loading) in a Colt SAA or a CA Bulldog pressure wouldn't seem to be too critical with a lighter weight bullet...?
 
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Thank you BD37. Very informative!. I looked through an older reloading manual I found on my shelf yesterday. Hornady Third Edition published in 1982. Interestingly, they only have 1 load listed for 44 special. A 240 grain lswc. And they have data using hs-6! Couldn't believe it! They actually say hs-6 showed the most promise under that bullet (the only bullet they used). Their max load is 8.6 grains so I loaded up 10 at 8.5 and 10 at 9. Gonna head to the range with my buddy in a little bit (with my chrony) and see what they do. My only concern is the seating depth. Every manual I've consulted sets the col at 1.5". The crimp groove on the bullets I'm using gives me a col of 1.453". I figure this deeper seating will increase the pressure in the chamber. By how much is anybody's guess I suppose. The manual also gives a working pressure of 14,000 cup for the special and 40,000 cup for the magnum.
 
Interesting!!!

Lyman manuals list the oal for their "keith" 429421 swc bullet as 1.570" in the 44spl cases.

With large cases/case capacity volume becomes less of an issue. Add to it that you're using a pretty slow burning powder that has less effect on case volume/pressure spikes.

Speer #12 has their swaged 240gr swc (1.475" OAL) listed with a max load of 8.0gr of hs-6.
 
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