.54 round ball rifling?

[Bucky182]

I hope this is in the right spot as I am new to the board. I am having a .50 call Renegade barrel re-bored to .54. I plan on only shooting round balls as I want to keep my flintlock hunting traditional. I am wondering what the ideal round ball twist would be or if there is a formula to figure it out. Also, does barrel length effect twist rate. For example a 26 inch barrel might be ideally 1:60 but a 30 inch might be 1:66? Just a thought. I am considering either a 1:64 or a 1:82 why because I like having stuff just a little different than everyone else! Which explains my 6.5/06 deer rifle. LOL

 

[Griz44Mag]

If you are sending the barrel to Bobby Hoyt, just tell him what you want to shoot out of it and he will take care of the rest.
For round ball it needs to be a slow twist - 1:60 to 1:70

 

[Larry Akers]

Either of the twists you mention will work for a .54. The 1:64 may be more particular about powder charge for best accuracy while the 1:82 will give you a wider window in the powder charge.

 

[Grenadier1758]

The slower the twist, the more likely you will need a large powder charge for optimal accuracy. A 1 in 60 twist may work well with a powder charge of 65 grains of 3fg, but it will take 100 grains of 2fg to get the same accuracy in a 50 caliber rifle. Its nice to want to be different, but if you use Bobby Hoyt to rebore the barrel, let him choose the best twist. Its okay to do the same as others.

 

[Sidney Smith]

My Lancaster is either 1/60 or 1/66. I get very good accuracy with 80 grains of ffg

 

[user 43911]

1 in 48 twist (that's my vote).

 

[Sparkitoff]

Depth of grooves vs. lands is a factor. I like 1:70 for .54 caliber. It gets good velocity with not a ton of powder. 70-90 grains with the right patch is super accurate. I have 1:60 and 1:66 .54's but the two 1:70's from different makers are the least picky about load.

 

[Bucky182]

Thanks guys yes going to bobby hoyt. DBrevit it has a 1:48 now. I don't want a compromise twist.

 

[erhunter]

Go with Bobby Hoyt, you won't be disappointed! I had a Lyman Trade 50 cal. rebored to .540, 1:60 twist, 7 lands, with .011 grooves and it shoots 1 1/2 inch groups at 70 yards. Bobby's your man. As other members said, tell him what ball size and weight you want to use and even maybe a starter patch thickness and powder charge and he will do the rest!

 

[user 43911]

Thanks guys yes going to bobby hoyt. DBrevit it has a 1:48 now. I don't want a compromise twist.

Why would you consider 1 in 48 a compromise twist. Some original PRB guns were this twist.

Even talked about on this forum back in 09 (link below)and many other places. I have seen the term "1/48 is a Compromise Twist" used many times before, not necessarily the case.
https://www.muzzleloadingforum.com/threads/original-hawken-barrels-question.52588/

 

[Bucky182]

DBrevit, I guess in more modern terms it is a compromise simply because is can shoot both PRB and conical bullets. I am looking for a pure round ball only twist.

 

[Loyalist Dave]

I am looking for a pure round ball only twist.

1:48 WAS a "roundball only twist" because it was popular when there was only round ball. But we know what you mean.

Slower twists in the past came about, partially because of the manner of the rifling. The grooves were not always the same width as the lands, and in fact were thinner. So in some cases, either from day one or as the rifle barrel wore, barrels being a lot softer metal than rifle barrels today, the depth of those thinner grooves could be or could become more shallow than today. Thus you then get the "skip" of the patched ball over the grooves and lose accuracy.

In the 19th century with modern machining, the rifling got better and more scientific. Some of the Minie Ball rifles were very slow twist, and the copies of those are so today. The Pedersoli repro of the 1853 caplock rifle aka the "three band" has a very slow twist rate of (iirc) 1:78 but shoots Minies very well. By the mid 1850's an offshoot (no pun intended) of the hunting community, gravitated toward very large calibers for round ball, and very slow twist rates. They were shooting rifles such as 8-bore [.85 caliber] and 4-Bore [1.2 inch ] with loads such as 165 grains of powder or 220 grains. They were still shooting at 100 yards, but they were shooting "dangerous game". A popular twist at the time was 1:120. James Forsyth came up with a customized type of rifling, that bore his name, and it was 1:108.

I don't think you're going to be shooting such stout loads from your Renegade at tigers nor elephants. So if you're going to Bob Hoyt, he can tell you what you need. If you had it done by somebody who was good at rifling but not "up" on black powder rifles, I'd suggest an observation. You will note that in all cases the makers of barrels for muzzle loading rifle builders, and the makers of the factory rifles, give their rifles at a minimum a twist that rotates the bullet, whether ball or minie, at least 1/2 turn before it exits the muzzle. Often it's more, but the 1/2 turn "rule" seems to not be violated. These companies live and die by their reputation for accuracy, so perhaps they know something?

So while a 1:82 would likely "work", it might not be an optimal twist for a Renegade barrel, since the ball would need to travel 41" to get a half turn before being release from the barrel's muzzle. Look at Green Mountain's website, and they offer the twist of 1:70 which means in a 36" barrel the ball has just completed a half-turn at 35" and then exits...their pistol barrels are 10" and all have a 1:20 twist.

Folks will often poo poo this observation, but it does seem to hold true for folks whose bread-n-butter are their muzzle loading barrels for round ball.

LD

 

[Zonie]

DBrevit, I guess in more modern terms it is a compromise simply because is can shoot both PRB and conical bullets. I am looking for a pure round ball only twist.

Some of the factory made guns like the TC Hawkens does have "compromise" rifling in their barrels but it is not a compromise just because of the twist rate.
It is a compromise because of the depth of the rifling grooves.

Barrels that are made for shooting long bullets usually have rifling grooves that are .003" or less in depth. Rifles that are made for shooting patched roundballs usually have rifling grooves that are .007"-.015" deep. The "compromise" barrels usually have rifling grooves that are about .005 deep. That is shallow enough to allow a elongated bullet to "bump up" and fill the grooves when the gun is fired but at the same time, it is deep enough for a cloth patch to get a grip on.

 

[user 43911]

Thanks guys yes going to bobby hoyt. DBrevit it has a 1:48 now. I don't want a compromise twist.

I agree with Zonie with regards to depth of rifling (last post above) in today's barrels over the rate of twist, if you had your barrel cut 10 thou groove depth and 1 in 48 twist you would have a very good .54 cal PRB gun (and not like many others today). The added plus would be if the need or want to shoot a heavier projectile came up you could shoot Minie"s as the hollow base does not need to have as much pressure to obtain enough obturation as the Minie' s skirt will flare to fill the grooves (even 10 thou, no so much with solid or R.E.A.L type).I digress, each to their own, 48 twist would work well as it has many time before.

 

[Bucky182]

Loyalist Dave, Zonie and DBrevit thank you all so much. I learned a lot and will tell Mr. Hoyt what I want the gun to do and let him figure out how to make it do it!!

 

[Bucky182]

Loyalist Dave,
Using your formula of 1/2 turn in the lenght of the barrel. My 26 inch renegade should have a 1:52

 

[Loyalist Dave]

Using your formula of 1/2 turn in the lenght of the barrel. My 26 inch renegade should have a 1:52

Yes, it's a general rule...well actually it's an observation. So a 1:48 isn't a bad twist rate for your barrel.

You should also know that the British between 1800-1807 figured out that for rifling to help at all, the ball needed a 1/4 turn. The Baker rifle, made famous by the Sharpe''s Rifles TV series originally had a 30" barrel with a 1:120 twist. That was partially to help with speed loading, and cleaning. That rifle's accuracy standard was much lower than what folks expect for hunting. In fact the repro barrels for that rifle are made 1:66... and still don't get that half-turn, but it's a lot closer.

Now on the other hand, the barrel makers don't know what you're going to do with your barrel, especially a straight sided barrel like those from Green Mountain. So say you bought a 1" wide, .50 barrel. It's going to be 36" long, with a 1:70 twist. So say you wanted it made into a half-stocked rifle similar to your Renegade, but just a tad longer. That's OK because the half-turn point is at 35"....or is it?

So the first inch or so at the breech, is tapped for the breech plug...not rifled...well that's OK because you still have 35" from the internal face of the breech plug to your muzzle, and 35" is half of the 1:70. BUT when you load your powder, your powder takes up a almost 2" in length inside the barrel, so...when you seat the ball on the main load, it's resting 33" from the muzzle...so it's getting slightly less than that 1/2 turn. IF your builder copied an existing plains rifle from the time period, or perhaps an English sporting rifle, the barrel might be shortened by as much as 4", which then would mean your ball is seated 29" from the muzzle. Still will probably shoot fine, because the bare minimum appears to be a 1/4 turn, and it does that after 17.5" of travel.

If the re-rifling you buy is at 1:56, you get that much turn after 14" of travel...just fine in your 26" barrel.

Now back to a previous post and theoretical figures....a 1:82 twist will "work" since it would give you in that 26" barrel a 1/4 turn by the time the ball had moved 20.5".

So bottom line don't worry about it, as you're going to have Mr. Hoyt do the work.

LD

 

[Kansas Kid]

Some of the factory made guns like the TC Hawkens does have "compromise" rifling in their barrels but it is not a compromise just because of the twist rate.
It is a compromise because of the depth of the rifling grooves.

Barrels that are made for shooting long bullets usually have rifling grooves that are .003" or less in depth. Rifles that are made for shooting patched roundballs usually have rifling grooves that are .007"-.015" deep. The "compromise" barrels usually have rifling grooves that are about .005 deep. That is shallow enough to allow a elongated bullet to "bump up" and fill the grooves when the gun is fired but at the same time, it is deep enough for a cloth patch to get a grip on.

That saved me a lot of typing. If I had my choice I pick a 1-56 to 1-60 with narrow lands and .010 to .013 deep grooves that are square cut. Loads super easy and shoots great. Good luck

 

[longcruise]

Folks will often poo poo this observation, but it does seem to hold true for folks whose bread-n-butter are their muzzle loading barrels for round ball.

Well, don't take any of this personally, but I'm in the "poo poo" camp.

The dynamics of stabilizing a ball or bullet come into play after the projectile leaves the muzzle. It's not reflecting on the length of the barrel it just exited or looking back to decide how it should behave.

Comparing balls and elongated bullets is pretty much a apples/oranges thing. Balls are pretty tolerant of variations in twist rate. I've watched a shooter with a fast twist 54 inline shooting patched balls with 90 gr of ff with pretty good accuracy. Twist rate, IMO, (and it's only opinion) get a lot of undue credit and blame for many shooting results.

Elongated bullets are a whole different dynamic from a ball. Its actually a very complicated science involving many factors. If you are feeling up to a mind bender, give this several long thoughtful reads. http://ffden-2.phys.uaf.edu/212fall2001_Web_projects/Isaac Rowland/Ballistics/Bulletflight/index.htm

The rifled muskets of old with the slow twist were in many cases shooting hollow base bullets that also behave differently from solid bullets.

There's just way more going on with projectile stability than a ratio of twist rate and barrel length.

Once again, please don't equate my opinions with a personal attack. I hold you personally in high respect. We just disagree on this one little thing that is relatively speaking a drop in the bucket.

 

[Griz44Mag]

Loyalist Dave,
Using your formula of 1/2 turn in the lenght of the barrel. My 26 inch renegade should have a 1:52

The stock Renegade barrel is 1:48 - so your measurement is right on (+\- a tad.)