Fun with the chrony

[Don]

Took my chrony out to the range today along with a few pistols. The first pistol I shot over the chrony was my Pietta Remmington Navy. I had loaded it a few days ago with 26 grains of pyrodex P and a wad and a 80 grain ball. I was surprised and disappointed with the performance. I had a high of 862fps and a low of 577fps with an average of 679fps. This loading should have easily had velocities in the 900fps territory. Theory: could have been because the load sat for a few days, could have been the greasy wad that may have neutralized some of the powder,could be that the chrony was clocking the wads instead of the balls or it could have been some other variable I'm ignorant of. What do you guys think?

I was pleased with the other pistols and their performance. I brought my Pedersoli screw barrel derringer and loaded it first with 10grains of Goex3f and a .454 ball. It clocked at 406fps with a energy of 51 ft/lbs. I switched to 10 grains of Pyrodex P and velocity went up to 479fps with an energy of 71 ft/lbs. Not bad for this diminutive little pistol. The last pistol I shot was my New Orleans Ace. I loaded it first with 20 grains of Pyro-P under a .433 ball and a .020 lubed patch. It crossed the chrony at 542fps with an energy of 80 ft/lbs. The max load I shot with the same ball and patch was 23 grains of Pyro-P with a velocity of 583fps and an energy of 92 ft/lbs.

I don't know what all this proves other than BP guns are indeed deadly but I had a lot of fun doing it. I definately want to redo the shooting with the Navy revolver and test a few more of my derringers as well as my revolvers.

Don

 

[mykeal]

Not quite sure why you were expecting >900 fps from the Remington with 26 gr of fffg. That seems a bit too high for that loading to me.

I'd rule out the chronograph tracking the wads as the other guns didn't appear to have that problem.

IF

 

[redwing]

Hand guns revolvers vary from chamber to chamber. With a gun of that type fire all your test loads from the same chamber. I would fire 5 from each chamber. You will find each chamber will deliver a different speed.
That is why some 6 guns cost more than others. It cost more to fit hand guns to be uniform. Shooters that use these for Compt. have them timed and aligned. They will most often have the chambers pugged with gun steel and redrilled to line with the bore. The barrel forcing area will be fitted to the cylinder face to reduce gas loss.
Care should be taken when making a magnum load for an import of this type. Good luck and be safe. :hmm:

 

[Don]

I'm basing my assumtions on Mec's book on percussion revolvers. In his book a .380 ball shot from the .36 cal Remington had a velocity of 1181 fps with a charge of 28 grains of Pyrodex P. With just 2 grains less of powder I thought it reasonable to expect 900 to 1000 fps velocity. The other guns had patches not wads but I am prone to agree with your theory that the lube from the .36 wads contaminated my powder and reduced its energy. I didn't anticipate this problem so I didn't bring the things I needed to test a fresh load. I will report in the future about the results of a fresh load. I'm guessing this is why Wild Bill Hickcock shot and reloaded his Colt Navies on a daily basis.

Don

 

[Zonie]

The Lyman "Black Powder Handbook" 2nd ed says a .36 cal revolver with a 7 1/2 inch barrel will produce a muzzle velocity of 897 FPS with a load of 25 grains of Pyrodex P and 920 FPS with a 27.5 grain load of Pyrodex P.

The 285 FPS variation your data shows indicates to me that something is happening in each chamber and your guess that powder contamination is the cause may be right.

Of course the chambers in a cylinder aren't quite the same and the nipples do vary too but I wouldn't expect to see that much variance in velocity.
zonie

 

[mykeal]

Zonie provided the number I was trying to remember from the Lyman handbook, except I remembered wrong. I was thinking 800 and forgot the 97 part :redface: ...about 900 is right for that load.

 

[Leatherbark]

My Pietta 51 will do around 900 or so with its 7-1/2 inch barrel and a full load of 3f Black. Once I tried an equivelant load of 777 and insantly noticed it had more recoil.........After chronographing the load I saw why......1130 fps. After 3 cylinder loads of that I noticed my cylinder pin was loose as a goose in the steel frame where it threads in.........After repair it was no more 777 for me.........................Bob

 

[rebel727]

777 is about ten percent stronger than black.

 

[Blizzard of '93]

I'm figuring powder contamination by lube. had it happen to me, MOF. now I either pre-grease the slugs or put just a dab of grease atop the felt. have left mine loaded for long stretch that way and no trouble. some have advocated toilet bowl ring wax as sealing lube atop projecticle, supposedly does not melt and does good as lube also.

 

[Tight_Wad]

I have an old Lyman pistol & revolver handbook (1978) which lists various loads for a repro Colt Navy .36 with 7 1/2" barrel.

26.0g G-O FFFg + 81g RB = 1079 fps / 209 ft lbs

21.0g* Pyrodex P + 81g RB = 823 fps / 123 ft lbs

*given as 'max' loading

Tight Wad

 

[torn moc]

I dont know about that MAX load..My Uberti .36 Colt cylinder will accept 40 grains and still seat a Ball...it kicks!

 

[Zonie]

Powder must have gotten weaker over the years. :rotf:

The Lyman 2nd Ed of the Black Powder Handbook shows the same gun with Goex FFFg 30 grain load gives a muzzle velocity of 889 FPS and a 30 grain Pyrodex P load is 942 FPS. :hmm:
zonie

 

[Russ T Frizzen]

27 grains is about all I can get into my Navies--35 grains is a cylinderful in my '60 Armies. Don't think my Navies would take 40 grains even if I was to crush the heck out of the charge. You must have some seriuosly oversized chambers in that cannon!