P-Max Swiss Powder Calculator

[rodwha]

I was recently informed of this ballistics calculator based on Swiss powders. I thought the 3F loading was a little on the light side, but not by a whole lot (25-50 ft/lbs). I decided to see what 4F said and it was drastically sharper.

https://www.p-max.uk/cgi-bin/black_powder.cgi

I have long desired a Colt 1862 Police with a 4.5” barrel, which seems to be discontinued now along with the 6.5” version. I have figured that if I were to keep the projectile length to a hair under that of ball it could still hold a full ~20 grn max charge, yet have a lot more mass and a very wide meplat. It would likely weigh 110-115 grns. From what little chronographed results with conicals/bullets it’s on the light side of a .380 ACP at about 175 ft/lbs, which the calculator’s figures were slightly higher. But when I used 20 grns of 4F it really woke it up out of the 5.5” barrel.

A huge reason why it’s just not been very high on my list is that it just doesn’t seem all that useful, it’s just a range toy. I’ve often thought that if it could just reach .38 Spl performance it could be a lightweight pack piece. Well, with 4F it shows a pretty significant increase figuring a 110 grn bullet.

How are these proofed and what kind of pressures are they designed to work with? Certainly not looking to blow a cylinder wall out.

And so now I’m curious what others that own these think of them. Yes, if you’re using standard Goex it’s going to be really anemic. But what if those of you using Olde Eynsford by Goex, Swiss, Triple7, or Pyrodex P? And what of you who use 4F?

 

[rodwha]

What I’ve been rather interested in is what it figures my Remington NMA Sheriff’s model should get. So far it’s best load is 32.5 grns of 3F Olde E or T7, and it doesn’t seem to matter what projectile I use so I intend to dial in this pistol and my ROA and fill in the excess chamber capacity with a wide meplat bullet. As is I estimate it to weigh about 230-235 grns. So in essence I figure it should be hotter than the old 28 grn charge under a 230 grn bullet. If I recalculate it for a 7.5” barrel it’s a little hotter than the military load so I figure I’m in the ballpark. However from other posted results using similar powders I figured the numbers should be a bit higher. I’m not too interested in using 4F in my .44/.45 as they’re plenty potent, but for giggles I had to see. Wow!!

I can’t lie and say I’m not curious though. Turns the NMA from a .45 ACP to a +P, which would be really nice were I having to go through the brush looking for an unhappy hog. The Hazard’s paper cartridges, using what they referred to as Pistol Powder, was 4F and found to be quite similar to Swiss, and these loaded with 36 grns and shooting a 211 grn bullet. If only it weren’t such a pointy bullet they would have been more devastating.

 

[45D]

What I’ve been rather interested in is what it figures my Remington NMA Sheriff’s model should get. So far it’s best load is 32.5 grns of 3F Olde E or T7, and it doesn’t seem to matter what projectile I use so I intend to dial in this pistol and my ROA and fill in the excess chamber capacity with a wide meplat bullet. As is I estimate it to weigh about 230-235 grns. So in essence I figure it should be hotter than the old 28 grn charge under a 230 grn bullet. If I recalculate it for a 7.5” barrel it’s a little hotter than the military load so I figure I’m in the ballpark. However from other posted results using similar powders I figured the numbers should be a bit higher. I’m not too interested in using 4F in my .44/.45 as they’re plenty potent, but for giggles I had to see. Wow!!


View attachment 337419

View attachment 337421

View attachment 337422

View attachment 337423

I can’t lie and say I’m not curious though. Turns the NMA from a .45 ACP to a +P, which would be really nice were I having to go through the brush looking for an unhappy hog. The Hazard’s paper cartridges, using what they referred to as Pistol Powder, was 4F and found to be quite similar to Swiss, and these loaded with 36 grns and shooting a 211 grn bullet. If only it weren’t such a pointy bullet they would have been more devastating.

Those are pretty respectable
numbers but I don't think you can get to +p pressure. +p pressure is 23,000 psi.
Using a standard energy calculator, a 230gr bullet at 1000fps = 510 ft.lbs
1100fps = 617 ft.lbs
1200fps = 735 ft.lbs
I know these numbers are for a 5" barrel so an 8" barrel ( '60 Army) would be more . . .

Mike

 

[rodwha]

Those are pretty respectable
numbers but I don't think you can get to +p pressure. +p pressure is 23,000 psi.
Using a standard energy calculator, a 230gr bullet at 1000fps = 510 ft.lbs
1100fps = 617 ft.lbs
1200fps = 735 ft.lbs
I know these numbers are for a 5" barrel so an 8" barrel ( '60 Army) would be more . . .

Mike

I’m sorry, I was vague. I didn’t mean pressures but velocity/energy figures of the .45 ACP +P.

 

[RMH]

Those calculators are interesting to play with, and may tell you relative changes in velocity you might expect but:
You have to actually chronograph your pistol/rifle with the loads in question to see if they are even close to the estimated velocities in the calculator. I used that very same program and double checked my 45Cal. flint SMR and .54 Cal. Woodsrunner against a chronograph with my preferred loads. The actual velocities were off by as much as 200fps. (corrected to actual muzzle velocity, the program seemed to be optimistic)

My experience with revolvers (unmentionables) is an even greater loss due to cylinder gap gas losses when compared to pressure barrel figures. I should point out that factory published ballistics usually turn out to be wildly optimistic when actually put to the test in guns that people actually hunt with. No two guns are the same. Speer ran tests on a series of consecutively serial numbered S&W revolvers with the same lot of ammunition and got almost a 300fps difference between them.

I guess what I am saying is don't get your panties in a bunch over paper ballistics. Given adequate penetration it is bullet placement that counts.

 

[rodwha]

Those calculators are interesting to play with, and may tell you relative changes in velocity you might expect but:
You have to actually chronograph your pistol/rifle with the loads in question to see if they are even close to the estimated velocities in the calculator. I used that very same program and double checked my 45Cal. flint SMR and .54 Cal. Woodsrunner against a chronograph with my preferred loads. The actual velocities were off by as much as 200fps. (corrected to actual muzzle velocity, the program seemed to be optimistic)

My experience with revolvers (unmentionables) is an even greater loss due to cylinder gap gas losses when compared to pressure barrel figures. I should point out that factory published ballistics usually turn out to be wildly optimistic when actually put to the test in guns that people actually hunt with. No two guns are the same. Speer ran tests on a series of consecutively serial numbered S&W revolvers with the same lot of ammunition and got almost a 300fps difference between them.

I guess what I am saying is don't get your panties in a bunch over paper ballistics. Given adequate penetration it is bullet placement that counts.

Oh, absolutely you’d need to chronograph to know. I don’t care quite so much about the particulars as it’s going to be quite capable even down to .44 Spl performance (~300 ft/lbs). It’s nice to know though, and one day I may get a chronograph as I do find the ballistics fascinating.

What really stood out to me is the peak pressures it states are likely. I’ve been reading up on it a little with what little there is to read, and with nothing absolute, but it seems the idea is that these would likely be roughly that of the .45 Colt, up to 14,500 psi. According to the calculator I’d be close to that pressure using 3F, but would exceed it quite a bit were I to load 4F.

The bullet designs I’ve made were created to leave larger bearing surfaces to increase the pressures a little. The driving bands for my Ruger only versions are much longer. I had been contemplating lengthening by a few hairs the lower driving band. And I had always figured one day I’d try 4F Swiss as others have, and 4F was commonly used in pistol calibers even into the metallic cartridge days as Curator has pointed out. But those anticipated pressures has me looking side eyed at it. So I assume my pressures, and subsequently the velocity, would be a little higher than posted. I’m kind of a jack of all trades, master of none. I don’t know enough to make decisions like that so it seems prudent to idly ask. Don’t doubt I’d have no concerns using it with a ball. And if I ever get a Pocket Police I’ll almost certainly have some of that on its way, and would try it.