Minie Air Gap?

[Steel Horse Rider]

After reading the question about using a shotgun slug in a muzzle loader I started to wonder about the void in the back of a minie ball. If the minie or a slug is not rammed hard into the powder charge wouldn't you have the dreaded "air space" in the chamber that is supposed to make BP guns into bombs? Could someone enlighten me?

 

[hawg]

After reading the question about using a shotgun slug in a muzzle loader I started to wonder about the void in the back of a minie ball. If the minie or a slug is not rammed hard into the powder charge wouldn't you have the dreaded "air space" in the chamber that is supposed to make BP guns into bombs? Could someone enlighten me?

No because there is no gap where the outside of the bullet is concerned. The dangers of an air gap are overated anyway. Take a percussion Sharps for instance. There's no way to get rid of some air gap. Mine had a recommended charge of 80 grains. With a bullet seated it would hold 110 grains of loose powder. That's quite a gap. Even with the chamber full you would still have a gap at the breechblock. Now if you had an inch or so between bullet and powder that would act as a barrel obstruction with explosive results.

 

[woodnbow]

No because there is no gap where the outside of the bullet is concerned. The dangers of an air gap are overated anyway. Take a percussion Sharps for instance. There's no way to get rid of some air gap. Mine had a recommended charge of 80 grains. With a bullet seated it would hold 110 grains of loose powder. That's quite a gap. Even with the chamber full you would still have a gap at the breechblock. Now if you had an inch or so between bullet and powder that would act as a barrel obstruction with explosive results.

Fadala did some experiments with this and he had to create a substantial air gap from charge to projectile before the barrel burst. I’m not saying how substantial because as foolproof as modern bp arms are, I’m sure there’s a fool out there waiting for a challenge.

 

[Mike OTDP]

Proper procedure with a Minie is to ram the bullet home firmly.

 

[.38 Special]

Fadala's experiments were, to the best of my recollection, done with seamed, mild steel tubing. Just recently, Muzzleblasts magazine did an extensive test with real barrels and couldn't damage them no matter how ridiculous they got with air gaps and overloads. I personally believe the "air gap" is closer to myth than reality.

 

[hawg]

I remember back in the early 70's Turner Kirkland of Dixie Gun Works took one of their flintlock pistol barrel blanks and made a pipe bomb out of it. All of the pressure came out of the touch hole with no damage to the barrel blank.

 

[LaneP]

Agree with the air gap blowing up guns being overrated. It's more to do with consistently seating the bullet in the same manner each shot, and firm contact with powder column is a baseline you can feel for in the loading process. Consistency is the name of the game whether you're loading modern metallic smokeless ammo or ancient smokepole designs.

 

[Armored farmer]

I was invited to help out at a 'Fellowship of Christian Hunters' field day. The idea was to get local youth interested in hinting/fishing/outdoors. They had various activities set up along a hiking trail at our local State Park. Archery. 'Hawk throwing. Casting a lure.....etc
I was asked to help out at the muzzleloader shooting event. There were a couple of young guys there that had a t/c inline. 50 with a scope. They were loading with 50gr 777 pellets and pointed plastic sleeved sabots, and letting the kids shoot it at a target. I was just hanging back talking to the kids. After about a dozen shots, I noticed the guys having problems loading the rifle. They were really leaning on the ramrod. A shot or two later the sabot hung up about halfway down the barrel. It wouldn't budge. The guys proceeded to prime and 'shoot it out. I had been only a casual observer, but I stopped them. There were a dozen kids standing around waiting to shoot. The guys said, "oh I've had this happen before....I just shoot it out..." MAAAH...not today you're not!
I had them remove the breech plug and push the mess out of the barrel, and give it a proper scrubbing. I explained that they had just made a bomb and were going to set it off with a group of kids hanging around.

I wasn't real popular with the young guys who had the inline, but I'm glad that I was there. Everything would have been okay.....probably......?
They didn't invite me back the next year..

 

[woodnbow]

Fadala's experiments were, to the best of my recollection, done with seamed, mild steel tubing. Just recently, Muzzleblasts magazine did an extensive test with real barrels and couldn't damage them no matter how ridiculous they got with air gaps and overloads. I personally believe the "air gap" is closer to myth than reality.

I’m pretty sure the one I recall was using copper tubing. (Type L 1/2” copper tubing is .545 caliber i.d.)One end of which was stuck in a coffee can full of concrete for a breech. Cannon fuse to light it off. It’s been a long time and that particular book is up in the attic for the time being. So I could be way off base…

 

[.38 Special]

I’m pretty sure the one I recall was using copper tubing. (Type L 1/2” copper tubing is .545 caliber i.d.)One end of which was stuck in a coffee can full of concrete for a breech. Cannon fuse to light it off. It’s been a long time and that particular book is up in the attic for the time being. So I could be way off base…

My copy is just about as accessible, but I think you may be right. It's been an awful long time.

 

[Steel Horse Rider]

Back to the subject of Minie balls, my understanding of their purpose was to speed and simplify the reloading process in the Civil War so I am not too sure that they would have been rammed firmly home before each shot.

 

[JCooperfan1911]

Fadala's experiments were, to the best of my recollection, done with seamed, mild steel tubing. Just recently, Muzzleblasts magazine did an extensive test with real barrels and couldn't damage them no matter how ridiculous they got with air gaps and overloads. I personally believe the "air gap" is closer to myth than reality.

True, but some of the junk out of India that people buy use such tubing for their bores.

 

[.38 Special]

I dug out Sam's Black Powder Handbook and found the relevant chapter. It was indeed "copper conduit" which nicely took a .54 ball. He made the "breeches" out of soup cans filled with molten lead, and reported that even 120 grain charges did no damage with the ball seated on the powder. The same load would bulge the "barrel" when short started. Undefined "lighter" loads didn't.

He also has a few notes regarding a rig made by gunsmith Dale Storey, which used actual rifled barrels. These apparently held up fine to short starting, but blew or ringed when a second ball was short started over the main load.

 

[Jim Watson]

A friend loaned his TC Hawken. The user shot it dirty and stuck a ball partway down and shot it out, bulging the barrel. TC replaced it but friend did not think the new barrel was as accurate as his low number original.

But I once read of the Swiss Federal with Wild System ramrod with positive stop about 0.1" off the standard powder charge.
And is there a gap between the Shutezen's powder only cartridge and breech seated bullet?

 

[.38 Special]

And is there a gap between the Shutezen's powder only cartridge and breech seated bullet?

That is a very good point. The standard advice - at least 30 years ago, during my very brief foray into that game - was to begin with a 1/16" gap and experiment from there. Many shooters apparently found a bit more than 1/16" gave best accuracy, in what was a surprisingly complex game.

 

[dave951]

After reading the question about using a shotgun slug in a muzzle loader I started to wonder about the void in the back of a minie ball. If the minie or a slug is not rammed hard into the powder charge wouldn't you have the dreaded "air space" in the chamber that is supposed to make BP guns into bombs? Could someone enlighten me?

No. It doesn't cause a problem. As pointed out earlier, the Sharps is designed that way.

Also, you do NOT have to slam, pound, cram, or beat the minie into the powder, just seat with a little bit of pressure to avoid damaging the nose and altering the flight characteristics of the bullet. But hey, what do I know, it's not like I'm an Instructor or black powder competition shooter or something.........

 

[Jim Watson]

While we are here...
The 1841 Mississippi rifles were put back/kept in service for the War.
Some were rebored to .58 for standard Minie balls, some got .54 Minies. But I read that those did not work out well, not as accurate as a .58. Zat so? If so, any ideas why?

 

[dave951]

While we are here...
The 1841 Mississippi rifles were put back/kept in service for the War.
Some were rebored to .58 for standard Minie balls, some got .54 Minies. But I read that those did not work out well, not as accurate as a .58. Zat so? If so, any ideas why?

Reports of a 54cal being less accurate need to be taken with a bag of salt. Are we looking at contemporary reports, some reenactor gossip, or what somebody who knows minies?

Contemporary reports are probably due to ammunition issues. In the competition world, a 54 "Mississippi" can be darn accurate. The barrel is essentially a "bull" barrel which helps with dampening shooter movement. It also resists barrel motion from the act of firing making the gun more stable. Fit the minie correctly, use quality components and know shooting fundamentals and you have a great rifle.

 

[hawg]

While we are here...
The 1841 Mississippi rifles were put back/kept in service for the War.
Some were rebored to .58 for standard Minie balls, some got .54 Minies. But I read that those did not work out well, not as accurate as a .58. Zat so? If so, any ideas why?

The 1841 Mississippi had a twist rate of 1:66 but I have read that some of the different contractors used a 1:72 twist. I think the rebored barrels were all a 1:72 twist like the 1861 Springfield. Since the 1841 was originally a round ball rifle the pitch of the rifling may not have worked well with minies.

 

[PWC]

38 Special said:
"I personally believe the "air gap" is closer to myth than reality."

Wouldn't it be more circumspect to say this applied to modern guns?

There are still a lot of original barrels that were hammer welded around mandrels that are still shooting BP.

 

[dave951]

The 1841 Mississippi had a twist rate of 1:66 but I have read that some of the different contractors used a 1:72 twist. I think the rebored barrels were all a 1:72 twist like the 1861 Springfield. Since the 1841 was originally a round ball rifle the pitch of the rifling may not have worked well with minies.

You would be surprised to find how little twist rates matter in a minie ball rifle for the most part

 

[.38 Special]

Wouldn't it be more circumspect to say air gap in modern guns?

There are a lot of original barrels that were hammer welded around a mandrel that are still shooting.

Probably. The point I was trying to make was that fears that "any sort of air gap in a muzzleloader will lead to explosions" is overblown, in my opinion.

Has it happened? Probably. Is it any more than the remotest possibility? I doubt it.

 

[hawg]

38 Special said:
"I personally believe the "air gap" is closer to myth than reality."

Wouldn't it be more circumspect to say this applied to modern guns?

There are still a lot of original barrels that were hammer welded around mandrels that are still shooting BP.

A minie acts like a round ball. It has all the weight forward so they do better with slow twist.

 

[SC45-70]

The 1841 Mississippi had a twist rate of 1:66 but I have read that some of the different contractors used a 1:72 twist. I think the rebored barrels were all a 1:72 twist like the 1861 Springfield. Since the 1841 was originally a round ball rifle the pitch of the rifling may not have worked well with minies.

I believe that the depth of the rifling has more to do with the accuracy of a minnie than the twist rate.
Years ago I had two 58 caliber barrels custom built specifically to shoot minnies. They were identical in every way with the exception of the rifling depth. 1 had a rifling depth of 4-5 thousands and the other had a rifling depth of 10-12 thousands.
The barrel with the deep rifling would not consistently hit the target at 25 yards, and when it did the minnies key holed. I tried several loads and never got this barrel to shoot a minnie. The barrel with the shallow rifling shoots the minnies great at 100 yards.

SC45-70