Just what goes on in there? Barrel

[hightime]

I can imagine that a fired bullet doesn't slip the rifling for a ways 'til it get a spinnin'. If so that would probably be leading and very little you could do about it. I guess in a pistol of at least four inch, she's a spinin' by the time she exits the muzzle. I see about 1 inch of rifling on my derringers. I don't think they're working. Maybe that's the real reason I have to be in the barn to hit the broad side.
Whoops. I think I'm headed back to burn rates and that obsternation or whar ever that word was.

Owen

[Pete44ru]

IIRC, projectiles start their turning at about the time the nose reaches the length of the projectile into the barrel's rifling.

While there may some skidding with certain projectiles and/or loads, I would think 4" to be very extreme, and indicative of a wrong projectile diameter.

.

[zzr7ky]

Some of the Derringer type and other low cost handguns may have less than ideal rifling to meet US legal requirements.

I have seen some scary simple single shots in Mexico/S. America that were smooth bores. Not importable since GCAof'68.

[Chuck 100 yd]

Proper bullets and load pressure (obturate properly) will
not skid over the rifling at all.

In BP rifle shooting the bullet will bump up while still in the cartridge case and be forced into the barrel by the building pressure. No skidding at all then.

[Cliff]

One thing I have read about gunpowder and its burning makes some sense I think. Gun Powder is a combination of Charcoal, Saltpeter, and Sulfur. When set afire, the combinations will burn, but the demons feeding on the sulfur will become constipated by the saltpeter. The carcoal is the intial heat the demons are trying to get away, but cannot do so being blocked by the steel of the gun they will eventually mange to push the bullet forward and run or fly screaming out of barrel, screaming and breathing sulfur and fumes as they try to get back to their domain. For this reason a lot of really old guns had the Hex signs on the muzzels and around the firelocks. Just a bit of trivia. Have a good day.

[Griff]

Aye, if that bullet strips thru any length of the rifling it'll leave chunks of itself behind. If you're seeing leading in the 1st 4" of the rifling, 1 of 3 things is wrong: 1- bullet diameter, 2- velocity, & 3 bullet hardness. #s 2 & 3 can work in combination and could be viewed as the 4th item... I tend to view them as separate, but equal parts in the equation.

Safe, accurate, effective ammunition (reloads) is a balancing act. Some might view the ability to develop superior ammuntion as an art form, but there is a science behind it... but sometimes there might just be a little magic in finding that perfect combination!

[BigSky56]

Hightime, reading your posts about your troubles with cast bullets and tight spots in your barrels, there is a fix you can lap the barrel with a cast bullet that has been coated with a type of paste like JB bore compound or a valve grinding paste second you can fire lap witch means using a coated bullet load it up and fire it. There is a treatise on this method at http://www.beartoothbullets.com/bullets ... n=book.htm then you need to read Glen Fryxell info @ http://www.lasc.us/Fryxell_Book_Contents.htm the one thing I learned is to match the PSI(how fast you push them) to the hardness of the bullet. Hope this helps you. danny

[earlmck]

Safe, accurate, effective ammunition (reloads) is a balancing act. Some might view the ability to develop superior ammuntion as an art form, but there is a science behind it... but sometimes there might just be a little magic in finding that perfect combination!

+1 on Griff's thoughts. And you'll probably want to look at bullets that are light-for-caliber (ie, "short") because they stabilize easier when you can't much velocity and the twist rate may be a little slow. Get a bullet of large enough diameter to fill the barrel and short enough to be stabilized by the rifling twist and surely you'll be able to at least hit the barn from the outside...

[AJMD429]

I can imagine that a fired bullet doesn't slip the rifling for a ways 'til it get a spinnin'.

You sound like you'd be a fan of Pope rifling...!

I don't doubt that the bullet slips only a little bit on engaging the rifling (look at a fired bullet if you can recover it, and the rifling grooves cut into the bullet won't be much wider than the lands in the barrel - but of course the highest velocity bullets are hard to capture intact to see this).

What I wonder about is how much slippage occurs between the relatively-hard-and-relatively-low-density-jacket-engaging-the-rifling, vs. the relatively-soft-and-relatively-high-density-core slipping against the jacket. I'm sure someone has studied this, and the relative bonding types with jackets and core. I can't imagine that there isn't slippage there.

[Cliff]

Don't forget Gain Twist rifling which was supposed to avoid these problems. I don't know if anyone does this anymore, it did have it supporters. Good Luck...........

[harry]

Don't forget Gain Twist rifling which was supposed to avoid these problems. I don't know if anyone does this anymore, it did have it supporters. Good Luck...........

They still do gain twist but it is for barrel torq not bullets slipping in the groves for the most part,
http://www.bartleinbarrels.com/Trifling.htm

[hightime]

Are you saying they had a twist rate that increased as the bullet traveled though the barrel.?

Owen

[harry]

Are you saying they had a twist rate that increased as the bullet traveled though the barrel.?

Owen

Have; S&W has it in the 460, bench rest shooters use it and I have a 6mm barrel with it.

[Chuck 100 yd]

Gain twist is not new. Many target rifles had it 100 years ago.

[hightime]

I feel so stupid sometimes. Ther's just so much to learn and I'm already old.
Anyway , I guess I'll just keep plugging along and ask questions when I need to. At least I can get answers.
The persuit of knowledge is the new game and the rifles are test.

Owen