1/48 twist & round ball?

[david w]

A 1-48 twist is a compromise for either round ball of conical. If you load a round ball too heavy. you lose accuracy. Dedicated round ball rifles are better off with 1-66 or 1-70 twist rate. Round balls have almost no sectional density and need very little spin.

 

[LME]

Hesp, I have built over 150 muzzleloaders from .36 to .58 caliber, with twists from 1 in 48 to 1 in 84, IIRC, and tested them all from the bench with a wide range of loads. I can tell no difference in accuracy that I could attribute to the rate of twist. Here is my second copy of Jim Bridger's Hawken with a 1 in 48 twist Oregon Barrel. The 120 grain powder charges of Olde Eynsford 1 1/2F were measured with a weight- corrected measure. (If you left-click the picture, it will enlarge).
View attachment 113833

At what distance were the targets? I have sighted in several rifles for others and never could use a stout load in a 1/48 twist barrel?

 

[Herb]

Both targets are labeled 50 yards, shot from bench.

 

[mooman76]

A 1-48 twist is a compromise for either round ball of conical. If you load a round ball too heavy. you lose accuracy. Dedicated round ball rifles are better off with 1-66 or 1-70 twist rate. Round balls have almost no sectional density and need very little spin.

Twist rate also depends on caliber. 1-48 twist for a 32 cal is about right for RB and not so good for conical. The larger the caliber, the les twist you need to stabilize the projectile and in turn of coarse the smaller the caliber, the more twist you need.

 

[Stony Broke]

The 1-48 is basically considered the mid point as far as twist. A guy could get slightly better results, depending on load, ball size, and all the other factors....but basically a 1-48 can be set up and do a good job with either RB or conical. It is just in the middle where it can be made to work with either.

 

[Okie Hog]

An option may be to find a rifle you want in .50 and send the barrel off to Bob Hoyt to re-bore into a 54 slow twist.(?)

^^^^^This.

Find a .50 caliber with roached barrel. Send the barrel to Mr. Hoyt for re-bore to .54 caliber with slow twist rifling.

My ,50 caliber Navy Arms barrel was re-bored and rifled to .54 caliber by Mr. Hoyt. Barrel has rounded grooves. This target has the first seven shots from that barrel. First shot was to the right and i adjusted. Second shot was high and i adjusted again and fired a five shot group. Distance is 50 yards.

i used a .490 ball and unwashed drill cloth patch, a tight fit that required a couple hard whacks on the short starter.

 

[LME]

Both targets are labeled 50 yards, shot from bench.

After looking at your post again and blowing up the targets I see that your targets were at 50 yards. I am a Neanderthal when it comes to computers!
I thought you said you were using 120 grains of powder in a 1/48 twist barrel? The last rifle I sighted in was a T/C .50 cal. rifle 1/48 twist barrel. I started with 80 grains of powder behind ball and kept down until the top accuracy of the rifle was reached. Accuracy was best with 60 grains of powder. I also shot a .54 cal. rifle with a 1/66 twist rifling and top accuracy was reached at 80 grains of powder. The latter rifle has shot a three shot group with one oval hole at a hundred yards. I haven't been able to maintain good accuracy with heavy loads and would like to know how you do it?

 

[Herb]

Yes, I used 120 grains, thrown from a measure that I calibrated to hold 120 grains BY WEIGHT of OE 1 1/2F. I did it specifically to test the twist. I fired four groups of 20 shots of even much heavier loads in this rifle with equally good results, but I will not post those pictures nor loads here.

In a .54, I shoot 50 grains of either Goex 3F or Goex 2F in our local matches, all off-hand. Eighty grains of either is a good load in a .54, almost standard.

I have never found a "sweet spot" of best accuracy in any caliber, ever. But some loads are much better than others. Having shot tens of thousands of rounds through a couple hundred muzzleloaders over the years, I test until I find what works. For example, the first shots on the left target were with red duck cloth from Wal Mart and one blew. I switched to some other red-colored patches I had, and one holed. On the right target a week or so later, I used linen that measures .016 with the ratchet on my micrometer but which can be crushed to .010, which is what happens when the ball is loaded. I like linen , but added a wool over-powder wad. I don't know if it was needed.

 

[LME]

Yes, I used 120 grains, thrown from a measure that I calibrated to hold 120 grains BY WEIGHT of OE 1 1/2F. I did it specifically to test the twist. I fired four groups of 20 shots of even much heavier loads in this rifle with equally good results, but I will not post those pictures nor loads here.

In a .54, I shoot 50 grains of either Goex 3F or Goex 2F in our local matches, all off-hand. Eighty grains of either is a good load in a .54, almost standard.

I have never found a "sweet spot" of best accuracy in any caliber, ever. But some loads are much better than others. Having shot tens of thousands of rounds through a couple hundred muzzleloaders over the years, I test until I find what works. For example, the first shots on the left target were with red duck cloth from Wal Mart and one blew. I switched to some other red-colored patches I had, and one holed. On the right target a week or so later, I used linen that measures .016 with the ratchet on my micrometer but which can be crushed to .010, which is what happens when the ball is loaded. I like linen , but added a wool over-powder wad. I don't know if it was needed.

I missed the part that you were using weight not volume. I use volume. That makes a difference I would think? The one thing I have found is there is a point where accuracy starts to fall off as the powder charge is increased.This has occured with every rifle I have shot in for people. This is not to say there is a way to change these results I am saying I don't know what it would be?

 

[hanshi]

I tend to load tight prb combinations that require the muzzle crown to be relieved. Most of my rifles have grooves of from about .012" to .016". But a sort of an anomaly exists with one rifle. It's a .54 with a 1-66" twist and a very accurate round ball shooter with charges from 60 grains of 3F up to 110 grains of 3F. Thing is the groove depth is only .006". While not truly "shallow" it's not too far from being shallow. It's an excellent shooter with .530" ball and a rather "thin" patch. The other rifles are normally patched with .023" - .024" canvas or denim. A couple use cotton duck or mattress ticking about .018" (+ or -). This suggests that general statements do not always apply as there are exceptions.

 

[Herb]

LME, my charges all were MEASURED, using a measure I made to hold exactly 100 grains of OE 1 1/2F by weight with no tapping or settling. I make such measures for each powder, grade and weight. Why do I do this? The photo below shows some powders I use and measures I cut for them. The powders From left are Goex 2F with a 100 grain and an 80 grain measure,, Goex 3F, Swiss 3F, Swiss 1 1/2F and the first Olde Eynsford 1 1/2F sold at Fort Bridger. (The label reads "test sample NOT FOR RESALE.)

The rifles I made are my first copy of Jim Bridger's Hawken, .54 caliber, an early .54 Hawken I made from a blank, and my first .58 fullstock flint "Hawken" style. Left-click to enlarge this picture, then read the target. I shot Swiss 1 1/2F measured with my 100-grain Goex 2F measure, BUT those charges weighed 117 grains! No wonder Swiss is hotter when you just use volume measurement.

 

[leadhoarder]

That would blow up the narrative that you get more shots to the pound with Swiss because you can reduce your charge. That was with 1.5f? 2f would be more drastic.

 

[BadDaditood]

Hesp, I have built over 150 muzzleloaders from .36 to .58 caliber, with twists from 1 in 48 to 1 in 84, IIRC, and tested them all from the bench with a wide range of loads. I can tell no difference in accuracy that I could attribute to the rate of twist. Here is my second copy of Jim Bridger's Hawken with a 1 in 48 twist Oregon Barrel. The 120 grain powder charges of Olde Eynsford 1 1/2F were measured with a weight- corrected measure. (If you left-click the picture, it will enlarge).
View attachment 113833

Herb, thanks for posting your research, that’s a lot of work.
However, since Goex and Olde Eynsford are extinct can you please repeat all your tests with Swiss and Scheutzen?
…on all 150 rifles?
Thanks!! ;-)

 

[LME]

LME, my charges all were MEASURED, using a measure I made to hold exactly 100 grains of OE 1 1/2F by weight with no tapping or settling. I make such measures for each powder, grade and weight. Why do I do this? The photo below shows some powders I use and measures I cut for them. The powders From left are Goex 2F with a 100 grain and an 80 grain measure,, Goex 3F, Swiss 3F, Swiss 1 1/2F and the first Olde Eynsford 1 1/2F sold at Fort Bridger. (The label reads "test sample NOT FOR RESALE.)

The rifles I made are my first copy of Jim Bridger's Hawken, .54 caliber, an early .54 Hawken I made from a blank, and my first .58 fullstock flint "Hawken" style. Left-click to enlarge this picture, then read the target. I shot Swiss 1 1/2F measured with my 100-grain Goex 2F measure, BUT those charges weighed 117 grains! No wonder Swiss is hotter when you just use volume measurement.

View attachment 1141

I appreciate you being so free with your information. I wasn't around many B.P. rifle shooters and learned what little I know from trial and error.
Your picture of the rifles you have made are beautiful! The Bridger Hawkin is absolutely beautiful!

 

[Herb]

LME, thanks. That picture was taken before I had finished the stock. Here is what it looks like now, the second one down. I have hunted deer and elk with it and shot it a couple thousand times. The top is a closer copy of the Bridger Hawken , with the 48-inch twist, unfortunately, the only roughly shaped stock blank available from Knob Mountain (which had been recommended to me as a good fit) was way too highly figured. The bottom two are lighter rifles based on Kit Carson's Hawken.

Baddaditood, the table is of some powder comparisons I have made. I have never had Scheutzen.

 

[Herb]

Oops- don't know how I got two pictures of the last one and can't delete
the second one.. If the moderator can delete the extra one, please do.

 

[LME]

LME, thanks. That picture was taken before I had finished the stock. Here is what it looks like now, the second one down. I have hunted deer and elk with it and shot it a couple thousand times. The top is a closer copy of the Bridger Hawken , with the 48-inch twist, unfortunately, the only roughly shaped stock blank available from Knob Mountain (which had been recommended to me as a good fit) was way too highly figured. The bottom two are lighter rifles based on Kit Carson's Hawken.

Baddaditood, the table is of some powder comparisons I have made. I have never had Scheutzen.View attachment 114232View attachment 114246View attachment 114254View attachment 114254

Very nice work! I have always been partial to percusion Hawkin rifles. I presently use a Ithaca Hawkin which I prefer over other rifles I have and have had. Your rifles are so nice that if I had one I would be to scared to use it. I would start to cry if I put a scratch on it. I have only one major regret that being I never knew anyone that shot B.P. rifles when I started. What little information I got was from books and trial and error.

 

[Herb]

LME, the thing about building copies of rifles as they look today, such as the Bridger Hawken, is that any handling marks add to the look. They are good. I took the first copy to the Fort Bridger Rendezvous and carried it around. Nobody paid any attention to it. I got a buffalo burger and smeared grease all over the stock. Anything goes.

When Robert Redford, the actor of the movie Jeremiah Johnson, had the Green River Rifle Works make him a Hawken, he didn't like the new look. Carney, who worked there, told me the builders then took turns beating dents into the stock with tools. I also heard, and it might be true, that Redford tied a lasso to the rifle and dragged it down a gravel road behind his pickup.

Here I am hunting elk with my first Bridger.

 

[Frontier's]

My traditions, cva guns shoot both patched balls and conicals well under 2 inches at 100 yards. All of them are a 1:48 twist.

A lot of this so called compromise twist myth, comes from the crappy TC barrels. The TC Renegade is the only model that I've found to shoot PRB with great accuracy. Their hawken model has been the worst with prb. Never have been a TC fan to begin with, but that super shallow rifling was intented for their maxi balls.

 

[Wildrangeringreen]

1:48 In .54 caliber is pretty fast, we're talking fast enough to stabilize 600gr bullets lol. I make my express rifles in .54 in a 1:70, that allows you to shoot 300-350gr bullets and round ball well, without requiring high velocity for the ball.

There is no set rate of twist that is ideal across all bore diameters, velocities, and projectile shapes. Generally, the heavier the bullet is per the length, the slower the twist can be at the same velocity. The larger the bore, the slower the twist can be for the length of bullet. The faster you drive the bullet, the slower you can have the rate of twist. A ball, while not very realistically efficient, is very stable in transit, and requires very little rpm to overcome imperfections in the ball and loading errors, so technically, you can get away with less twist if you are going to shoot only ball. In my experience, shallow groove rifling doesn't hurt accuracy with a patch, I get average 1.75" rested groups at 100yd with a shallow groove barrel .50 I have (it's the only rifle I have that gets loaded exclusively with ball). You just need to use a thinner patch.