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Gents,

I have a 4 bore muzzle loader with a 46 inch barrel, percussion action and a Parker Hale p53 nipple. It has a 1980's Birmingham Proof mark and 8 drams black powder stamped onto the barrel next to the proof marks.

When I have taken slow-mo videos of it firing I have noticed a lot of unburnt powder coming out the end. Therefore I am considering using a finer powder to assure that all powder is burnt in the barrel pushing the shot. Currently I am using 8 Drams of Swiss No5(1Fg) behind 4Oz of shot. I am considering changing this to Swiss No3(2Fg). In the hope that a finer powder will produce more velocity. Is there anyway of calcuating the changes in pressure and velocity this will cause?

Is a normal musket nipple and cap sufficient to get all that powder burning? An old boy has suggest not and suggested I put a few grains of the finest black powder behind the nipple to help it ignite the main charge. Not sure I am convinced.

Also Greener in his book The Gun suggests a light 4 Bore load of 8 Drams and 3Oz Shot and a heavy load of 9 Drams and 3 3/4 Oz shot. Does anyone have any thoughts on this? Does anyone have any other 4 bore load data?

Thanks

Tom

bigteeth

I have no data for you I'm afraid Tom but I have a question....
Are you still stood up after firing 4 oz of lead?

Gazza wrote:I have no data for you I'm afraid Tom but I have a question....
Are you still stood up after firing 4 oz of lead?

It’s ok, it can catch you unawares if you don’t know what’s coming.

Are you sure it is all unburnt?

What is the barrel length? Is that the one that was cut back?

dromia wrote:Are you sure it is all unburnt?

What is the barrel length? Is that the one that was cut back?

Barrel is 46 inches long. It’s the one I showed you at the Yarners. Im pretty sure it’s unburnt you can see a spray of burning flakes come out the end.

You get that with any M/L, black is an inefficient propellant with around 50% coming out as fouling after combustion, I would be more interested in how it patterns with the load than worrying about burning flakes exiting the muzzle.

If this supposed "waste" bothers you then work down the load 'till it stops, but I doubt it will. A white sheet laid down in front of the muzzle will help you capture and identify the ejecta.

We aren't talking metallic cartridge/smokeless combustion/internal ballistics here.

Would a finer grade of powder produce higher muzzle velocity?

The Gun says it’s proof to 8 drams of black powder. What grade and type of powder would the proof house of used. Without this information isn’t a blackpowder proof mark worthless.

TomEnfield wrote:Would a finer grade of powder produce higher muzzle velocity?

The Gun says it’s proof to 8 drams of black powder. What grade and type of powder would the proof house of used. Without this information isn’t a blackpowder proof mark worthless.

My logic being that 8 drams of Swiss No1 is a whole different ball game to 8 drams of corse nutty slack.

Depends on the load, it certainly will combust faster.

TPPH was and could still be the proof house powder in my day, I can't say what they used in Greeners day. I no longer speak with the proof houses.

TPPH is perhaps a shade faster/finer than Swiss No4, it was the go to powder for the Enfield rifles.

My worry would not necessarily be over pressure but polo mint patterns with the faster powders/bigger loads.

As in all things you need to try and see what works in your gun.

Swiss is the most energetic/highest pressured grain for grain of the current crop of black powders.