Broach Rifling/Twist

[Zulch]

Reading about the different rifling methods lately to educate myself. I came across an article.
I've noticed that some of the replica Colt's that I've looked at online and or purchased have broach rifling.
Just wondering if all replica's, regardless of make, used this process from day one? For instance my Uberti 1851 Navy made in 1962?
I've also read that from a mass production aspect, broach rifling is fast and economical.
   On another note, a military historian that I know recently told me that the rifling in the original Colt BP revolvers had a different
"twist"?? from todays replicas? He explained it like this. He said that the original BP Colt's rifling cuts were such that the conical
or ball would start slower in the early stage of propulsion and as it travelled down the barrel it increased in velocity? Please, love to hear
from anyone here on this topic. Fascinating to me, elementary to some ;-).
Link to Article:  https://www.nrafamily.org/content/3-methods-of-barrel-rifling-pros-vs-cons-2/

[Hawg]

Colt revolvers of the time did indeed have gain twist rifling as did the Remingtons. A little known fact is that until about 1860 Colt navies had a left hand twist and after 1860 had a right hand twist.

[Zulch]

Colt revolvers of the time did indeed have gain twist rifling as did the Remingtons. A little known fact is that until about 1860 Colt navies had a left hand twist and after 1860 had a right hand twist.

Thank you Hawg. I appreciate the input. We’re the Colts broach rifling during that time period?

[Hawg]

Colt revolvers of the time did indeed have gain twist rifling as did the Remingtons. A little known fact is that until about 1860 Colt navies had a left hand twist and after 1860 had a right hand twist.

Thank you Hawg. I appreciate the input. We’re the Colts broach rifling during that time period?

No, broach or button rifling wasn't invented until the end of the 19th century. Colt revolvers were single point rifling. Each groove was cut one at a time and required several passes to get to the correct depth.

[Zulch]

Interesting Hawg, is that the same as “cut” rifling

[Hawg]

Interesting Hawg, is that the same as “cut” rifling

Yep

[G Dog]

Z, there are two "speeds" involved.  One is the linier velocity, straight down the bore and the other is angular momentum, spin.

Progressive rifling / gain twist starts the projectile with a 'looser' twist to help the lead catch the groves and then (progressively) tightens up (gains twist) to put on maximum angular momentum.  That helps stabilize the projectile. Especially useful on heavy slugs.

There are many ways to describe that.

[Hawg]

Z, there are two "speeds" involved.  One is the linier velocity, straight down the bore and the other is angular momentum, spin.

Progressive rifling / gain twist starts the projectile with a 'looser' twist to help the lead catch the groves and then (progressively) tightens up (gains twist) to put on maximum angular momentum.  That helps stabilize the projectile. Especially useful on heavy slugs.

There are many ways to describe that.

Progressive rifling is where it gets deeper. Gain twist is where it speeds up.

[G Dog]

You are correct, Hawg.  The terms are often incorrectly used interchangeably and I picked up the bad habit. 

Does gain twist and progressive usually come on the same gun?

[Hawg]

You are correct, Hawg.  The terms are often incorrectly used interchangeably and I picked up the bad habit. 

Does gain twist and progressive usually come on the same gun?

No. I don't know of anybody that used/uses gain and progressive on the same gun but I won't say none have.

[Zulch]

Colt revolvers of the time did indeed have gain twist rifling as did the Remingtons. A little known fact is that until about 1860 Colt navies had a left hand twist and after 1860 had a right hand twist.

Any ideas Hawg as to why they would have switched from left hand twist to right hand twist? Significance?

[Zulch]

Z, there are two "speeds" involved.  One is the linier velocity, straight down the bore and the other is angular momentum, spin.

Progressive rifling / gain twist starts the projectile with a 'looser' twist to help the lead catch the groves and then (progressively) tightens up (gains twist) to put on maximum angular momentum.  That helps stabilize the projectile. Especially useful on heavy slugs.

There are many ways to describe that.

G. Thank you for that explanation. It makes good sense to me. On another note, if one were shooting an RM 8" barrel in .45 cal and another RM 8" barrel in .38 cal at a 100 yard target would they be comparable, meaning could you expect the same or similar grouping? I realize that we are also talking about a larger projectile and powder grain difference. I think? Z

[Zulch]

Thank you both, Hawg and G for the input. I am still learning an I really appreciate those who are willing to help me along the way. Means a lot to me. 

[Hawg]

Any ideas Hawg as to why they would have switched from left hand twist to right hand twist? Significance?

I have no idea why. I don't think there's any real significance. Some people think a left hand twist will torque the gun into the shooter allowing him/her to shoot better and some say that a right hand twist is more likely to unscrew the barrel. I have never heard of a properly torqued barrel unscrewing itself.

On another note, if one were shooting an RM 8" barrel in .45 cal and another RM 8" barrel in .38 cal at a 100 yard target would they be comparable, meaning could you expect the same or similar grouping? I realize that we are also talking about a larger projectile and powder grain difference. I think? Z

At 100 yards you would have to be an expert shooter to even begin comparing groups between .45 and .38. At a more reasonable range say 25 yards groups would be comparable.

[Zulch]

Any ideas Hawg as to why they would have switched from left hand twist to right hand twist? Significance?

I have no idea why. I don't think there's any real significance. Some people think a left hand twist will torque the gun into the shooter allowing him/her to shoot better and some say that a right hand twist is more likely to unscrew the barrel. I have never heard of a properly torqued barrel unscrewing itself.

On another note, if one were shooting an RM 8" barrel in .45 cal and another RM 8" barrel in .38 cal at a 100 yard target would they be comparable, meaning could you expect the same or similar grouping? I realize that we are also talking about a larger projectile and powder grain difference. I think? Z

At 100 yards you would have to be an expert shooter to even begin comparing groups between .45 and .38. At a more reasonable range say 25 yards groups would be comparable.

Thanks Hawg. I appreciate your input. I'm learning, thank you, Z