Determining safe powder loads?

[user 63484]

I know this is a question that has tons of variables and probably multiple answers but I find myself looking for some advice as I just picked up a new gun.

And I’m sorry if this has been asked before but my google kung fu was coming up short on this one.

This new gun that’s got me asking about this is a Cabelas Hawken style in 54 cal that’s been bored out to 58 smooth bore.

And just to get ahead of the curve here, yes it shoots just fine with 60-70gr of 2f and I doubt there is any need for anything more.

I would however like to know a system to determine safely how far these charges could be taken. With this and any other gun that’s either maybe heavily used/older, modified like this one, or I simply don’t have access to a factory manual with loading data.

My first intro into BP shooting was the cheapest traditions 50cal rifle I could find. And once in a while with the recommended max charge of 2f smacking a steel plate hard enough to knock the stand over would make my inner child light up a bit, good times. But a brand new gun with a factory manual had me more at ease for that sort of recreation.

I’m really not trying to take my guns out to their limit, but I’m a very analytical, numbers oriented person. And I just love accurate data, so having this gun with zero info on this topic just rubs me the wrong way.

I really don’t think I have any interest in pushing this gun past 80gr of 2f but I feel like I should have a time tested system for developing safe and effective loads as a BP shooter.

Any advice or information would be greatly appreciated.

 

[Johnny Too-Tall]

Best answer is to ask the person that rebored it. It also matters if your shooting a PRB or shot as well. But you should have a 15/16" barrel and a .58 hole leaving .177 outside thickness. Which is just under 3/16" which is .1875

 

[TDM]

I think the main thing to consider is that any well made muzzleloader will handle 2-3 times the amount of BP than your projectiles will. That is the limiting factor. A patched round ball can only handle so much velocity before it strips from the rifling. Depending on caliber, that may be 50 grains for a .36 or 90 grains for a .58, and your most accurate load will be below these numbers. 70 grains for a .54 or a little either side is good. Now if your shooting conicals you will use heavier powder charges, 90 - 110 grains for .50's and 54's are normal. But if your rifle won't shoot heavy loads accurately it's a waste of powder. And it depends on your barrel twist as to whether you have a slower round ball twist, something in the middle like a 1:48 twist, or a fast conical twist. Just continue to experiment 5 grains up or down, if your using PRBs try some different patch thickness, and try some 3F if you have some.

 

[Dave Marsh]

TDM she's a smoothbore.

 

[TDM]

TDM she's a smoothbore.

Oh well...... then never mind.

 

[TDM]

TDM she's a smoothbore.

And I'm stone cold sober too. Got to remember to read better.

 

[user 63484]

Oh well...... then never mind.

Still good information, I hadn’t considered being able to accelerate a projectile fast enough to separate it from the rifling. But considering how soft most lead is that makes perfect sense and I would imagine it wouldn’t require an extreme amount of force either.

All the rifles I have I shoot round ball in. I have a flintlock hawken that is 1:48 (?) but everything else is 1:60/66 range I’m pretty sure. So I have never shot anything but RB, I would like to try some conicals out sometime though.

 

[user 63484]

Best answer is to ask the person that rebored it. It also matters if your shooting a PRB or shot as well. But you should have a 15/16" barrel and a .58 hole leaving .177 outside thickness. Which is just under 3/16" which is .1875

It was sold to me as bored out by Bob Hoyt. I’m assuming that has meaning to someone but I have zero knowledge of the players in this arena.

I’m shooting .575rb currently. Looking to pick up some overshot wads and some lead shot (found wads at TOTW but any leads on where to buy lead shot please chime in!)

“It also matters if you are shooting a PRB or shot as well.” Is this implying the load over the charge can have an effect on chamber pressure with a given amount of powder? Such as projectile(s) weight difference or maybe friction coefficient/drag on the barrel itself?

 

[Johnny Too-Tall]

It was sold to me as bored out by Bob Hoyt. I’m assuming that has meaning to someone but I have zero knowledge of the players in this arena.

I’m shooting .575rb currently. Looking to pick up some overshot wads and some lead shot (found wads at TOTW but any leads on where to buy lead shot please chime in!)

“It also matters if you are shooting a PRB or shot as well.” Is this implying the load over the charge can have an effect on chamber pressure with a given amount of powder? Such as projectile(s) weight difference or maybe friction coefficient/drag on the barrel itself?

Bobby Hoyt is well known reborer on this site. Many have his contact information here. But yes pressure is a big player in the loading game. For example if you have to hammer the ball in to load it, it will build more pressure due to drag and sealing it completely or close to it.

 

[Johnny Too-Tall]

Still good information, I hadn’t considered being able to accelerate a projectile fast enough to separate it from the rifling. But considering how soft most lead is that makes perfect sense and I would imagine it wouldn’t require an extreme amount of force either.

All the rifles I have I shoot round ball in. I have a flintlock hawken that is 1:48 (?) but everything else is 1:60/66 range I’m pretty sure. So I have never shot anything but RB, I would like to try some conicals out sometime though.

The conicals will shot well in the 1-48 twist. The 1-60 and 1-66 are round ball twist not saying the conical won't shoot well its just more suited for round balls.

 

[BeardedGunsmith]

I'm new myself to black powder and muzzleloaders but it was always my understanding that once you got to a certain level of powder, the "excess" would remain unburned. And after watching some guys on YouTube do an experiment by filling the whole barrel of an inline and ramming a saboted round before firing it remotely, that seems to be true. The rifle was undamaged and you could see the evidence of unburned powder on the table the rifle was on.

 

[Iceman]

any leads on where to buy lead shot please chime in!

Any gun store that sells reloading supplies will probably have it.

 

[Duk]

any leads on where to buy lead shot please chime in!)

I've been looking for lead shot locally for a while now everybody is out

 

[Notchy Bob]

A good place to start is the old-time rule of thumb, one grain of powder per caliber. That would be considered a light load now, and you could work your way up judiciously. I don’t know what your maximum charge would be. A lot might depend on the thickness of your barrel wall. Your barrel likely measures either 15/16” or 1” across the flats. I would be more conservative with the lighter barrel. In your smoothbore, assuming it really is .58 caliber, a .562” patched round ball would be a good choice. This ball size (and the mould to cast it) is readily available.

Your .58 caliber smooth bore is essentially a 24 gauge shotgun, and I think 2-1/4 drams of FFg (approximately 62 grains), with an equal volume of shot, with two card wads over the powder and one over the shot, would be a good starting shot load.

24 gauge was probably the most common bore size in 19th century smoothbored trade guns, although actual bore diameter was more commonly around .600”. A lot of the fellows here shoot trade guns, and could advise you regarding their loads.

Be safe, and have fun with your gun!

Notchy Bob

 

[mikesto44]

This was told to me when I first got into this sport.
Never exceed double the caliber of the gun for safety.
Example: 32=64, 45= 90 an so on. Maximum powder loads are not always best for accuracy. JM2C

 

[Rob M.]

Just start with low charges and work your way up while getting to k ow your firearm . Start with the same powder as your caliber standard , ie 50 cal = 50 gr. of powder ....start there always ... For long arms , of course . Pistols , half . You can always go up a little , but a little at a time ...

 

[flatcreek]

Quote

Just start with low charges and work your way up while getting to k ow your firearm . Start with the same powder as your caliber standard , ie 50 cal = 50 gr. of powder ....start there always ... For long arms , of course . Pistols , half . You can always go up a little , but a little at a time ...

I started with 40 gr, .395 RB and .018 patch in my 40 cal tenn mt and never looked back. It shoot great with that load.

 

[Rob M.]

Quote

I started with 40 gr, .395 RB and .018 patch in my 40 cal tenn mt and never looked back. It shoot great with that load.

Very cool . I still shoot 60 gr. in my .62/ 20 ga. ! Works great .

 

[gunpa]

Bobby would not bore it if there wasn't a good margin of safety. That's just the facts

 

[user 63484]

I've been looking for lead shot locally for a while now everybody is out

My closest shop is 100 miles away and doesn’t have much anything if you can even catch them open. I’m out in the middle of nowhere in the Texas desert, so I’m really looking for an online vendor.