Pressure

B

bigcountry11

New member
Ok, I am going to show some of my ignorance here. I am struggling to understand pressure for ball and cap revolvers like my 1848 dragoon.

I see data where people have shot 50gr of pyrodex RS, pyrodex P, 777p, swiss fffg, and goex fffg from a dragoon.

I always thought the dragoon could handle pressure of 50gr of fffg 50gr by volumn of black powder. Maybe the limitations wasn't pressure but amount it could hold??


1.) is it safe to shoot 50gr of 777P if you shoot 50gr of goex fffg? I always thought youhad to lower the charge 30% to be safe?
2.) Is shooting ffg in a revolver that is designed to handle 50gr of fffg black powder safe? Figured ffg would have lower pressure than fffg?
3.) Is this strickly safe to shoot all the ffg, and fffg, and pyrodex RS, and 777P you can put in a 1848 dragoon? In other words, its not pressure thats the limit but the amount of space to hold the powder/ball?

Does any of this make sense? I shoot alot of flintlock and precussion rifles, and know for instance, its not a great idea to substitute fffg for exact same volume of ffg.
 
I get it...you aren't necessarily looking for the most accurate load for your Dragoon. Like me you want to know what the largest display of smoke-n-boom you can make if you feel like doing it just for giggles.

Others will chime in and let you know what they think is the most accurate load. This is not what you are asking for. Some will frown upon your desire to make the most smoke-n-boom with your soot beltcher. I don't own an 1848 but rather I have a Walker. Here's the answer I think you are looking for.

With the exception of 777 you should be safe to cram in as much BP or BP substitute that you can fit in with reasonable compression. For an 1848 I understand the volume limit is 50 grains of BP. For 777 your target equivalent of 50 grains should be reduced down 15% or roughly to 42 grains of 777 max. In addition, you should not compress the 777 but rather the ball should be push down such that it rests on the 777 without an air gap. Lastly, some may warn you that, depending on the make/metallurgy of your 1848, you risk damaging your wedge or stretching other metal components over time if you shoot 50 grains continuously.

p.s. With the exception of 777 outlined above I don't think you have to worry about pressure. Just follow the directions of the manual that came with your revolver. Use a 0.454" lead ball or possibly a 0.457".
 
I don't own a dragoon nor do I shoot 777 but it should be fine with 50 grs. of 777. That would only be comparable to 60 grs. of bp. FWIW I'd don't see any difference with FF or FFF in my revolvers.
 
Thanks clem, just want to know the boundries. I mean, possibly could find accurate loads at 50gr of fffg swiss. Maybe I am wrong thats rare as turkey teeth.

So to give you a background, I am a long range rifle shooter and have reloaded for sepreme accuracy for over 2 decades. So in my world, pressure and accuracy is everything. But thats smokeless.

And shoot lots of different black powder rifles from flinters to inlines. A few hunting black powder pistols like traditions. But other than shooting goex ffg for the last 30 years in my flints, and shooting pyrodex and 777 in my inlines, thats the limit of my knowledge with blackpowder. My limit of tinkering has been shooting 5-8 different types of projectiles. And usually never find the most accurate load at max charges. But have on occasion.

So, I am coming into this world of cap and ball revolvers being totally ignorant. So, being a reloader, first and foremost is safety and understanding pressure and limits of those in my firearms. After I understand that, I go in two different directions, one being as you say, "making smoke and boom" or who knows, I might take it far, (and usually do with anything I go after) and seek out hawkeye load combos.

I have never considered myself much of a pistol shooter, and generally unlike rifles at 600-1000 yards, the pistol usually outshoots my ability. Even though I do have some long range pistolslike 460S&W and strikers or whatnot.

But saw a walker in action and only thing I could think of was, "thats freakin cool".

So I am just trying to find out a few questions I posted. And appreciate your advise.
 
First of all, I concur completely with what Clembert posted, with one slight exception: He didn't say specifically that 50 gr of 777 was unsafe, but he did imply that it was an exception to the generalization that you can't overload a percussion revolver. I would agree with Hawg that 50 gr of 777 in a Dragoon would be a safe, albeit in my opinion, inaccurate load. I do own a Dragoon (actually two Dragoons) and I have used 777 in both. My notes don't mention using 50 grains of that particular powder, but I'm sure I've come close if not actually having done it.

As far as 2f vs 3f in revolvers - I doubt if anyone could tell without shooting large sample sizes through a chronograph. The barrels are just too short, and the vent at the forcing cone will tend to mitigate the slightly larger pressure peak of 3f over 2f.

Finally, it's pretty much a universal truth in bp revolver shooting that a full chamber load is not an accurate load. The actual 'best' load for each revolver is a tbd, but it's pretty certain it won't be the max load no matter what powder is being used.
 
mykeal said:
He didn't say specifically that 50 gr of 777 was unsafe, but he did imply that it was an exception to the generalization that you can't overload a percussion revolver.
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I was probably already pushing my luck by giving advice on a type of Dragoon I don't own. Since I don't own one I didn't know the specifics of the 50 grain max load I've come to understand about the OP's particular revolver. Specifically, I didn't know if the 50 grain max load requires heavy compression of the powder to get the ball (and possibly wad) to fit. And since most of us understand that compression of 777 is best avoided I didn't want to give advice that would have yielded a +15% power/energy gain with compression to boot. Seems that the rule of not being able to overload a percussion revolver should have an exception for 777 to include a point concerning compression of this particular powder. I was certain, however, that ~42 grains of 777 would yield similar performance to 50 grains of BP so I stopped myself short to play it safe.
 
50 gr 777 safe ?

Myke u allways state that you should reduce 777 loads by 15% by volume,also didnt some of the original guns (walkers)blow up,because of heavy loads? factory recomended charge 30 gr pyrodex p 50 gr .777 would nearly be a double load .
 
I'll just chime in a lil' bit on this...first off I'd say a Dragoon would be safest along with a Walker shootin' 50gr of ffg 777, I'd use it for your inlines you'll shoot better groups with Black Powder & they will be more percisely accurate per grain by volume and compressed... all my BP loads are best grouped with Goex fffg @ 42gr ... I won't use 777 in a BP Rev. Ifin you do remember to use 15% less by volume than a regular BP load ... never said this afore, but would use Pyrodex before usin' 777 ffg, and never fffg in a BP Rev ... it does have a greater chamber pressure as does BP ffg&fffg or Pyrodex ffg&fffg.
Jus' rules I live by...
:cool:
 
The advice to reduce 777 by 15% is for obtaining equivalent performance with real black powder or, more specifically, Pyrodex.

50 gr of 777 is approximately equivalent to 58 gr of Pyrodex or real black powder. Using that much powder (of any kind) in a bp revolver is, to be honest, a waste of powder. The chamber and barrel are simply too short for the powder to reach it's full gas production. A good deal of the powder will likely be expelled unburned or burned outside the gun. It results in inconsistency from shot to shot. This is one of the reasons a full chamber load in a bp revolver is universally a poor load for accuracy. It's also one of the reasons it's so much fun, because you do get a good, loud report and lots of smoke and flame from the powder burning outside the gun. You can also set the range on fire, but that's another subject.

At any rate, using 50 gr of 777 is not, in my opinion, a safety issue in a bp revolver because a good portion of the powder will either be unburned or burned outside the gun. You won't actually be shooting a full 50 gr of 777.

Clembert makes a good point about needing to compress the powder to get a full 50 gr of powder in a Dragoon chamber along with a ball. Yes, a good deal of compression will be necessary, and compressing 777 will give very inconsistent results. It does not like to be compressed. Another reason why you won't get the full effect of all 50 grains.
 
Myke u allways state that you should reduce 777 loads by 15% by volume,also didnt some of the original guns (walkers)blow up,because of heavy loads? factory recomended charge 30 gr pyrodex p 50 gr .777 would nearly be a double load .
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Colt had cylinder cracking on the original Walkers because of, 1 metallurgy was in it's infant stages. 2 conical bullets loaded backwards. Not a problem with modern day replicas. People have reported loading a Walker full of T7 with out problems. Why you would want to is beyond me. It's a waste of powder.

These chamber full charges really don't give you that much more velocity, most of the extra powder is burned after the bullet has left the barrel.
 
I see folks chiming in that they know for "fact" that most of the powder is being blown out and is not increasing cylinder or barrel pressure, but like inmy reloading world, does anyone have any concrete data for this? I guess I can't put a pressure/strain gauge like I could reloading metallic cartridges.

And can anyone comment about using ffg powder like goex ffg or pyrodex RS. If I understand it correctly RS and ffg is larger granuals and hense you couldn't get 50gr of weighed load in a revolver anyway. Also the way I understand it is RS and ffg is slower burning made primarily for rifles with longer barrels so a 7" barrel pistol couldn't really gain anything? Is this silly thinking?
 
If I understand it correctly RS and ffg is larger granuals and hense you couldn't get 50gr of weighed load in a revolver anyway.
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Pyrodex is not weight equivalent to black powder, it's only a volume equivalent powder.

While you may have meant "volume equivalent load", you stated "50 gr. weighed load" with respect to loading Pyrodex RS which is a concept that we try not to confuse.

This poster recently shot a 50 grain load of Pyrodex in their Dragoon:

http://thefiringline.com/forums/showthread.php?t=412431

Also the way I understand it is RS and ffg is slower burning made primarily for rifles with longer barrels so a 7" barrel pistol couldn't really gain anything? Is this silly thinking?
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No, not silly thinking. IMO nothing would be gained over using Goex fffg or Pyrodex P except more powder fouling and a dirtier gun.
However, the more that Pyrodex is compressed, the higher the velocity that's produced - i.e. like when using a hotter primer.
Maybe you would enjoy this Lyman book:

http://www.lymanproducts.com/lyman/publications/black-powder.php
 
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Bigcountry11 said:
I see folks chiming in that they know for "fact" that most of the powder is being blown out and is not increasing cylinder or barrel pressure, but like inmy reloading world, does anyone have any concrete data for this?
Click to expand...
I'm not sure who said they knew for a fact that most of the powder was blown out and not increasing cylinder or barrel pressure. If you were referring to my post you may want to reread it.

A great deal of chrongraph data has been published on The Muzzleloading Forum with regard to this subject. It has been hotly debated. The data universally shows that after a certain point adding powder results in diminishing returns with regard to projectile velocity. For example, after the optimum point for a given barrel/projectile combination, adding 10% more powder will only achieve about 6-7% more velocity. A number of people reported finding unburnt powder on the ground in front of their firing point in those cases; there was no corroboration between the amount of powder expelled and the diminishing returns in velocity, however. I understand this diminishing returns phenomenon is documented in the tables in the back of the Lyman Black Powder Handbook, although I haven't seen them myself.

I should mention that the Lyman data, and the data published on The Muzzleloading Forum, were all for rifles. I make the assertion as obvious that the situation with respect to percussion revolvers is even more acute.
 
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