Home Forums Hunting & Shooting Muzzleloaders bore capacity question

this question is about a custom muzzleloader with barrel steel strong enough for modern guns.
If one put 250 grains of FF or FFF black powder in a .58 caliber muzzleloader behind a 500 or so grain minieball, do you think most of the powder would be burnt in a 28" bbl?
What would be needed,a longer barrel or a larger caliber bore or faster powder?

p.s. not everyone is the same size,strength,tolerance etc when it comes to recoil and things you may find uncomfortable others may not and vice versa.I was really wanting to know about the powder burn etc.I thank everyone for their input!

A thicker recoil pad......

No matter. You'll hate shooting that load.

Why? Why would i hate shooting that load? would it be inaccurate or something?
I'm 6'2" about 240 and work out as often as i can,and im able to handle recoil ok. Im not concerned with that aspect of it. I was wondering if all the powder is going to burn in the barrel at that length. Please elaborate if there is some reason you think that would be a bad load other than recoil.
Thanks for your input.

Other than recoil from hell. No, I don't think all the powder will burn. I don't believe a powder load half that size will burn completely.

Enough will burn to still be a stout load though. Especially, with such a heavy bullet. I'd also be concerned about overloading the barrel.

The best thing is to increase the loads slowly up to that amount, and chrono them to see where gains end.

Why would you want to shoot that load? It's around 50% more powder than any other published load I can find, and 150% more than the Goex website.

There's an easy way to answer your question though. Lay out a white sheet (or two) in front of the muzzle, load 'er up, let 'er rip, and see what ends up on the sheet. Probably work best if you shoot from prone.

Let us know how it turns out.

PS, I'm guessing your bullet will deform, your barrel will get leaded, and accuracy will be poor.

thankyou very much. the barrel is used for a wildcat smokeless cartridge that pushes 650 and 750 grainers to 2800fps with the pressure level of a 458 win mag,due to powder choices and longer barrels. If i used smokeless loads in it i could push 600 grainers over 2000.But i dont,because i like blk powder. I know the barrel will hold up. I was just trying to ascertain where the black powder stops giving velocity. And i think youre right,i need to chrono it and find the law of diminishing returns.

i thank you for your guess about bullet deformation. i think they publish data lower than the real deal to be safe. the barrel was designed and is used to push smokeless loads in modern guns,.585 caliber 650-750 grain max 2800 fps in a wildcat cartridge.I figured adding it to a ML would be a cool .58 caliber.
To defeat the things you said, could i use a modern fmj or safari bullet then lay out a sheet. great advice brother.thanks !

If you're talking about a cartridge rifle, you may want to ask the question on the black powder cartridge forum.

I own a 62 caliber hawken replica and have used a 600 grain maxi ball over only 110 grains of 1f powder to take an elk,I can assure you you get full penetration,even at 90 yards, on a diagonal raking shot so I doubt youll need more power

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? im sorry i thought i said muzzleloader.its a custom muzzleloader job. the barrel is modern gun type steel,thats all. i use blacpowder.

My .02.....

Methinks your best chance of success is running heavyweight .50 bullets in a .58 sabot, if elongated projectiles is what your after.

If it's speed your looking for with a big bullet, think about a Forsythe (sp?) rifled big bore roundball slinger.
Pacific rifle used to build a 12 bore underhammer flinging a 500 grain ball to 2,000 fps. with (if I'm remembering correctly) 200 grains of FF.
They also built an 8 bore with a neat double-nipple arrangement to help with ingnition that handled some pretty huge charges.

If you look at sheer velocity, it ain't easy to beat the ball, even with a sabot (with black powder). Conicals may have somewhat higher BC's, but it takes a pretty good stretch before they start to catch up in terms of speed (ergo, trajectory). I've NEVER seen any data anywhere that would get a bore-sized conical of reasonable weight for the caliber much past 1300fps with black powder. Look up a few BC's for rounballs, sabots, and conicals and play around on Hornady's calculator. It'll embarrass a few marketing gurus.

Of course, I'm one of the few left that still has some appreciation for the lowly roundball and black powder. They will do things that other forms of projectile and propellant can't, but the cool kids on TV don't get paid to pimp them....

This is why I brought up cartridges.....

Thanks for your .02 cents. i agree with you about the roundball,i have no problems using one.In .58 caliber it should retain velocity fairly well too. The barrel can use smokeless to push 600 grain fmj's to past 2000 fps, but i wanted to use black powder in it or pyrodex etc to hunt muzzleloading season with.
I also think youre right about the sabot.i thnk Hornady makes a .50 to .45 300 or so grain boattail sabot bullet. I think finding a sabot to fit .58 to .50 is a good idea. ill try to get fullbores moving as fast as possible too.thanks for the input. hey and thanks for the recommendation of new guns to look at,i appreciate it. Ive looked into custom bp guns like 8 bore doubles and .72 calibers made with smokeless barrels for high charges,and the best price i found was $1700 for a custom .72.
But then i found a guy that makes smokeless barrels that are in the .600 nitro express range and can put a .58 caliber barrel on the .50 cal muzzleloader i already have. For significantly less money.So my logic is to save thousands of dollars by swapping my barrel out and turning it from a deer gun to a grizzly gun.
I agree with you about roundballs and black powder,and they do shoot flatter and penetrate well which is the basis of their performance i think.
I will tell you in all the forums ive posted this question your response was reasonable and provided good info,that you know of a 12 bore using 200 grains FFg.So i propose to use 200+ grains in a .58 but ill use FFF so itll burn faster.

thank you for your input.

You might want to think again on those sabots. Im not away of any company that makes a 58x50 sabot. I may be wrong but i would be very interested if you have a link to such a sabot.

Overkill45,good to see you again,breaker 1-9. Id like to see that link for a .58/.50 sabot too. I found a real hookup on getting my CVA .50 barrel swapped out for a .58 smokeless barrel that will push 650 grain bullets to 2500+ fps using nitro powders,but since im keeping it black powder, i figure 250 grs FFFg should help that .58 ball out a little quicker.

All input is appreciated.

That would be a thick sabot, and probably wouldn't work that well.


What are you hunting?

im sorry sir, i must clarify: the barrel im having put on my muzzleloader was originally designed for large bore smokeless cartridges to push heavy bullets fast at pressures equal to a .458 mag.I just wrote to show that if it will handle that,it will handle 250 grains of blk powder. It is basically putting a modern strong steel barrel on a muzzleloader so i can use more powder and push my ball/conical faster.
sorry for any confusion.

No worries, let us know how it does.

Yes, the powder will burn. The bullet you speak of isn't that hefty. The barrel steel isn't the issue, but the nature of you breech plug and ignition system is.

.50 caliber, 800 grain patched bullet over 180 gr Swiss 1-1/2 Fg works.
.56 cal, 1300 gr patched bullet over 200 gr Swiss 1-1/2 Fg works too.

Wouldn't suggest such loads for conventional BP rifles but underhammer or sidehammer guns with platinum lined nipples or sealed ignition handle it just fine. It helps with recoil if they weigh 25-40#, give or take.