Cartridge pressure?

[rockquarry]

Good afternoon,
Just got home from day 2 of 44 special load development for my model 69 2.75 inch. Going to use this as my woods/hiking gun in NH.
Using hs-6 powder I loaded 10 rounds each of 8,9,9.5, and 10 grains under Missouri bullets rnfp 240 grain cast with a bhn of 12. Starline 44 special brass, cci 350 primers, firm crimp in the crimp groove. Oal=1.43 +/-.
So, jumping to the 10 grain charge, average velocity for 10 shots was 980 fps. This got me wondering what kind of pressures I was creating in the chambers. I'm assuming the revolver can handle it for I'm pretty sure even a relatively warm 44 special load is still lighter than a "standard" 44 magnum load.
But then I got to thinking (never a good sign) might the pressure I'm creating actually be on the higher side of what I want to feed the 69 a steady diet of? Wouldn't the shorter case, magnum primer and overbook charge bump the pressures up significantly?
I've searched the interwebs but couldn't really find a definitive way to calculate potential chamber pressures. Too many variables.
Anywho.... I figured I'd ask the fine folks here and hopefully I can be steered in the right direction.
Thanks

Stick with paper published book data and you'll be fine. If you must use something from the Internet, use reliable data from the large powder and bullet manufacturers/distributors. Accuracy should be the number one factor with velocity following closely behind.

 

[cracker57]

31 post with only 2 even mentioning accuracy, rockquarry and kadam win the prize.
Jeffery should be contacting you for your shipping address to sent the prize. haha

 

[rockquarry]

31 post with only 2 even mentioning accuracy, rockquarry and kadam win the prize.
Jeffery should be contacting you for your shipping address to sent the prize. haha

He may not have mentioned it in his post(s), but Forrest r is an accuracy enthusiast. There may be others as well, but many today see accuracy in the same light as they see developing shooting skills: it's a distant second in importance. Maybe that's why they shoot up close.

 

[Forrest r]

31 post with only 2 even mentioning accuracy, rockquarry and kadam win the prize.
Jeffery should be contacting you for your shipping address to sent the prize. haha

The thread is about pressure and more specifically about "what kind of pressure the op would get using xx.xxgr of xxxx using this xxxgr bullet".

Why would I even consider even mentioning accuracy within a thread where the op asked about pressure?

 

[mtgianni]

I really like the .44 Spl and have several revolvers in just that caliber, so, while I don't disagree with the folks above, I am interested in .44.

HS-6 is a fine powder but I have loaded it much in .44 spl - right now I'm fiddling with 10B101 a "surplus" (not a pull-down) powder I bought off the guy who runs G.I. Brass in Owensboro Ky. - it is claimed to be like Herco - which I figure is roughly close to HS6 (not in weight but similar pressure compared to the vel) but I find it is closer still to BlueDot (I imagine it varies with air space in the case?).

I know this - it is very accurate! I am pusing 240s (honest 240s not mislabled 230-235) at 925 out of a 3" - loads seem mild but no doubt are over the normal .44 Spl pressure.

Just Ramblin'

Riposte

Biggest problem I have seen with VV 10B 101 is bridging. It is difficult to run through a measure or funnel without having some stick. I make sure to tap a couple of times. It just slows the process down some.

 

[cracker57]

The thread is about pressure and more specifically about "what kind of pressure the op would get using xx.xxgr of xxxx using this xxxgr bullet".

Why would I even consider even mentioning accuracy within a thread where the op asked about pressure?

If x amount of powder gives the best accuracy with x bullet and the powder charge is somewhere within what the manuals say why would you worry about pressure instead of whats the most accurate.
Not picking a fight here, I just thought if someone asked the op whats the most accurate of your ladder loads and it looked like it was a safe load why over think the pressure thing. I have never found a max load to be the most accurate.
Peace

 

[rwsmith]

'Gordon's Reloading Tool' is free. I have downloaded it, but it has a BIG learning curve that I have yet to tackle. But a project like yours would be good motivation to learn to use it.

There is also a device that uses strain gauges to measure pressure. Here's the link that talks about it:

Strain Gauges for Chamber Pressure Measurements

It seems the website for the manufacturer of the kit is down for upgrades but they say they will be back. I would like to see for myself what it is composed of.

 

[Forrest r]

If x amount of powder gives the best accuracy with x bullet and the powder charge is somewhere within what the manuals say why would you worry about pressure instead of whats the most accurate.
Not picking a fight here, I just thought if someone asked the op whats the most accurate of your ladder loads and it looked like it was a safe load why over think the pressure thing. I have never found a max load to be the most accurate.
Peace

Thank you for the excellent incite!!!
Next time someone starts a thread with the title "Cartridge pressure?"
I will tell them everyone knows max loads are never accurate and they should do ladder tests looking for accuracy and forget about pressures.

I've read and tested a little bit with the 44spl over the decades. Mostly "hot" loads for use in a ccw snubnosed 44spl that I've carried/used since 1984/1985?. So when someone is looking for a hot load for a specific purpose and asks about pressure. I will try to answer if I can with sighted authority, IE publicized documentation from reputable sources. That 10.0gr load of hs-6 the op asked about is putting it mildly "hot".
John Taffin in the 70's ran 9.0gr of hs-6
In the mid 90's handloader mag did an article on the 44spl and used 9.5gr of hs-6
In the mid 2000's handloader magazine did an article on the 44spl and used 10.0gr of hs-6/22,000psi

IMHO:
2400 is a lot better suited for hot loads in the 44spl. Back in the 80's before alliant, hercules would send people to the major shoots in ohio (setup booths), namely camp perry and Vandalia for the trap nationals. I would talk to the reps and get their cards to mail my cast bullets to that person. They would want 20 of each bullet you wanted to test. I'd simply tell them the powder I was interested in and the "max" pressure range I was looking for. I still use that data to this day. One of the bullets I sent in was the bullet/bottom left, an h&g 200gr hp gc swc.

Anyway sometimes there's a reason for max pressure/hot loads. And surprisingly enough, sometimes accuracy is secondary.

 

[BLUEDOT37]

I have never found a max load to be the most accurate.

.

You don't think a SAAMI 44 Spcl max load (15.5K psi) can be accurate?

.

 

[Shibadog]

I agree with Jim Watson, the Model 69 is chambered in 44 Magnum, so just use 44 Magnum brass. This also avoids the potential for overly hot loaded 44 Specials to find their way into a weaker revolver chambered in 44 Special.

This. I shoot warm "Special" loads a lot, but I always use Magnum brass. A 200 grain "silver bullet" (Lasercast) at 1000-1100 fps makes a fairly soft shooter that still hits pretty hard.

 

[jerffey]

Thanks Shibadog. That's probably what I'm going to do. What powder are you using and how much for your 1100fps load?