Pressure of my 12 bore?

[Togo]

Wow 350grs 777?? That's heavy! Sounds really cool he took it to Africa..

He didn't shoot the Cape in Africa, he found one in the states at a ranch somewhere $$$$, he was a member of Safari Club Internation and held a few records

 

[Blackpowder8bore]

No sir the 1 1/4thickness is going to be for the 12 bore

 

[Blackpowder8bore]

He didn't shoot the Cape in Africa, he found one in the states at a ranch somewhere $$$$

Yes that is money..but a buffalo is a buffalo

 

[Blackpowder8bore]

You said your builder already has a barrel with a 1-1/4 breech. What material is the barrel?

An 8 bore is .835 diameter. That gives you a breech wall thickness of .2075 inches.

If your builder is saying a .2075 wall is sufficient for a shoulder cannon, I would find another builder.

You'll need a huge lock too. Chambers makes a massive Virgina/Colonial flintlock that will work well on large breech rifles. They're rated for a 1-1/4 breech.

The 8 bore is not 1 1/4. It's already built and takes 350grs of powder+ball and it's diameter is 1.375.

The 12 bore is not built and its diameter is 1 1/4...

Do you think this is sufficient??

 

[Blackpowder8bore]

Sam Falada wasn't the sharpest knife in the drawer.

He sounds cool

 

[64Springer]

My .69 smoothbore has a .300 breech wall. So it's a 1.300 breech.

C-Num spoke of a 1-3/8th diameter. That sounds like a good start for .715/12ga bore.

 

[billraby]

With round ball the pressure is going to be fine. With conicals the pressure will be higher and probably best to reduce the powder charge. I would not be using large charges of 777 with conicals. That will increase the pressure even more.

I am using 1700 grain balls with 450 grain powder charges in my 4 bore. Rifle weighs 17 pounds. The recoil will knock you back a few feet but it is not painful. I have never gotten a bruised shoulder. It does NOT detach retinas, give you a concussion, or make you spin around. Anyone used to high recoil guns can shoot it without much trouble.

 

[Bunk]

for you big big bore guns what about a slug over 1000 grains and propelled by 12 drams of black powder.
Wat till the end when he shoots one. The "light" target load.
Not ML mostly but does talk about one ML Stopping Rifle and is interesting
ghttps://youtu.be/MDYtxxRU_cY

 

[52Bore]

12L14, leaded, was created for free machining screw making. Douglas Bbl stopped using it completely, years ago, and friend Jim K. who was the Metallurgist expert witness during the trials agrees - don’t risk using it with bullets.

I don’t believe Jason at Rice will cut you a bullet gun out of 12L14 either.

I built a 12b out of 4140 with no issues and shoot a mild load with a 850gr conical, I’m only shooting Whitetails..
Good luck, be safe.

 

[Blackpowder8bore]

Thank everyone for their input. It has all been helpful or cool to hear!!

 

[Blackpowder8bore]

12L14, leaded, was created for free machining screw making. Douglas Bbl stopped using it completely, years ago, and friend Jim K. who was the Metallurgist expert witness during the trials agrees - don’t risk using it with bullets.

I don’t believe Jason at Rice will cut you a bullet gun out of 12L14 either.

I built a 12b out of 4140 with no issues and shoot a mild load with a 850gr conical, I’m only shooting Whitetails..
Good luck, be safe.

Do you think a 1 1/4 wide 12bore barrel out of 12l14 steel is safe? The barrel company said it was the common ML steel.

 

[Blackpowder8bore]

for you big big bore guns what about a slug over 1000 grains and propelled by 12 drams of black powder.
Wat till the end when he shoots one. The "light" target load.
Not ML mostly but does talk about one ML Stopping Rifle and is interesting
ghttps://youtu.be/MDYtxxRU_cY

Thank you

 

[Mike in FL]

I wouldn't put 777 in anything. I'm not afraid of 12L14 for muzzleloaders, but others wet their drawers at the mention of it.
I have no idea what the pressure is, but that many grains of real black powder and that weight of projectile will be safe with 12L14, depending on how big your breech is. I'd recommend 1 3/8" to 1 1/2" at the breech. Finished weight for the gun should go 14 to 18lbs or so, unless you want to pick yourself up off the ground a lot.
What beastie is it that you're going to slay with such a large projectile?

The man said no negativity.

 

[Comfortably_Numb]

The 8 bore is not 1 1/4. It's already built and takes 350grs of powder+ball and it's diameter is 1.375.

The 12 bore is not built and its diameter is 1 1/4...

Do you think this is sufficient??

It might be. If I were planning on me being the one pulling the trigger I'd want the breech much closer to 1 1/2 inches. I made a big 11 bore Hudson valley fowler with an 1 3/8" breech and it was fine. Of course, It wasn't loaded as heavy as what you're doing, and it wasn't rifled.

11 bore HVF

 

[user 34300]

I know nothing of 777.

I do know black. Shooting a 0.990" ball in my 4-GA (1") 350 grains of 1F is reasonable. It pushes but is not violent. 350 Grains of 2F is very unpleasant. 350 grains of 3F will give you a concussion, at least it did me. Consider running 1F in large bores as was done originally.

If 777 accelerates the ball like 2F or 3F you might find yourself regretting it.

 

[FishDFly]

Sam Falada wasn't the sharpest knife in the drawer.

Amen.

 

[FishDFly]

I am inquiring about the psi of a rifled 12 bore muzzleloader shooting 250grs of 777 and a 600 grain conical or similar round ball. This is its max and common load for a 12 bore used in Africa. I'm choosing a steel for a similar rifle and need to know so i can pick the steel! 4140 or 12L14.

Anybody with knowledge of pressures in big bore muzzleloaders please help!

Please no negativity just trying to find useful info.
Thank you

Why not send a note to the makers of 777, they will be able to tell you?

 

[tenngun]

Sam Falada wasn't the sharpest knife in the drawer.

I’m wondering why you said that. Navy arms were great products and Sam was informative. While one can not pick his work his information was pretty sound

 

[beardedhorse]

I hunt with a 12 gauge smoothbore using a patched.715 caliber round ball over 120 grains of FFg black powder. Barrel is a Curly Gostomski Sitting Fox trade gun barrel. The charge is more than sufficient and actually overkill for white tail bucks. I carry it during bear and elk season too. The reason for the heavy load. It kicks like a mule with a walnut half stock.
James Gefroh (sp?) of northern Colorado made muzzle loading express rifles in 4 and 8 bore and some smaller. He and his clients successfully harvested BIG game in Africa. I don't have breech and barrel pressures for Triple Seven as I don't shoot anything but black powder. Maybe James does. I hunt for the meat and hides and have to get proper shot placement to keep damage to a minimum. Let use know which barrel steel alloy you choose.

 

[beardedhorse]

The 12 gauge Curly Gostomoski "Sitting Fox" barreled (smooth bore) trade gun I hunt with works well with a .715 patched round ball over 120 grains for FFg black powder. Don't know what the breech pressures are. It is more than sufficient for white tail and mule deer and loaded this heavy for seasons where I have an elk or bear tag. Kicks like a mule.
James Gefroh of northern Colorado made and hunted 4 and 8 bore muzzle loading rifles. Both he and his clients were successful in harvesting really big game in Africa. He might be able to recommend a certain alloy of steel for your barrels. He had a machinist make breech plugs and tangs for those express gun barrels..