Understanding the different rate of barrel twists and most compatible projectiles

[ETipp]

I've always thought that a 1:66" twist provided the best accuracy for round ball. I've noticed that many of the old long rifles have/had a 1:66" twist, or close to it.

I was also under the impression that a 1:48" twist was good for Maxi Ball style conical projectiles. Yet some folks state they obtain great accuracy with RB out of 1:48" twist ML. Even the Traditions .32 caliber squirrel rifle has a 1:48 twist and its for shooting RB.
Personally, I have not had the best of luck with 1:48" twists ML and RB but have gotten very good accuracy out of Maxi Balls in the 1:48" twist ML.

And then we have the new inline ML which I assume has a different rate of twist yet.

So, I'm a little ambiguous on this. Anyone care to clarify the differences and most compatible projectiles for each?

 

[deermanok]

Along with twist rate, the depth of the rifling is a factor.
I have an old CVA Missouri rifle 54 caliber, 1/48 twist barrel.
It will put just about every ball in the same hole at 50 yards. I tried some 54 caliber Powerbelts and they shot like crap.
I have another rifle, same twist that won't shoot a ball worth a darn but it will shoot good with any conical.

 

[ETipp]

Along with twist rate, the depth of the rifling is a factor.
I have an old CVA Missouri rifle 54 caliber, 1/48 twist barrel.
It will put just about every ball in the same hole at 50 yards. I tried some 54 caliber Powerbelts and they shot like crap.
I have another rifle, same twist that won't shoot a ball worth a darn but it will shoot good with any conical.

Interesting for sure. I need to educate myself on the rifling depth thing as well.

 

[Idaho PRB]

The rate of twist is also relative to the caliber. A 45 caliber round ball twist may be ideal at 1-48 while a 58 caliber may need 1-70, a 50 cal 1-66, etc. Some round ball barrels are 1-110". These numbers are for example only. Also, powder charge makes a big difference. Try backing off the powder charge in the 1-48 for round balls and see what happens. Also toy with patch thickness, slickness of lube, etc.

 

[ETipp]

The rate of twist is also relative to the caliber. A 45 caliber round ball twist may be ideal at 1-48 while a 58 caliber may need 1-70, a 50 cal 1-66, etc. Some round ball barrels are 1-110". These numbers are for example only. Also, powder charge makes a big difference. Try backing off the powder charge in the 1-48 for round balls and see what happens. Also toy with patch thickness, slickness of lube, etc.

I understand what you are conveying about bore size and rifling twist. I reckon that's why the Traditions .32 has a 1:48" twist but still suppose to be a very accurate RB rifle. I am, however, still curious as to why some of the smaller caliber KY and TN style long rifles have 1:66" twist.

I did try different patches and thickness. Also, different size round balls from 490" to 495". To tell you the truth, its been so many years since I've tried to shoot a RB I have forgotten whether I tried backing down the charge. Sounds like a good thing to try though.

 

[deermanok]

I owned a Crockett rifle, sold it 2 years ago.
That little gun shot great with a ball and 10 to 15 grains of 3f.
I found some conicals for it but the balls just shot better.

 

[ETipp]

I owned a Crockett rifle, sold it 2 years ago.
That little gun shot great with a ball and 10 to 15 grains of 3f.
I found some conicals for it but the balls just shot better.

After doing some research on that rifle, it appears to fit what I am looking for, for the most part anyway. Lots of positive videos on them. Hunting squirrels with one of those would be a great offseason fun as well as good exercise.

 

[Idaho PRB]

I do not believe manufacturer's always pair up the barrel's rate of twist on their rifles for one specific projectile due to availibility of mass produced barrel stock and to appeal to a wider audience, also almost all barrels will shoot something well given the right recipe. Look at ML pistols which typically have a very fast twist but shoot round balls well (reduced charge). This is all my $.02 and based on my experience. Others here know much more than I. Just try different things, something will work for you.

 

[anonymouscowherd]

TL;DR - there is ideal twist rate and then the ranges of twist rates that will actually work, the 1"48 is a mostly happy medium that seems to work well for most but the only way to be sure is to try it.

When it comes to twist rates there are 3 things that affect the "ideal" - muzzle velocity, bullet diameter and bullet length, or rather the ratio of bullet length to diameter (until you get into weird shapes/designs). A longer skinnier shape in relation to the diameter needs more rotations per second to stabilize and fly true.

Now if you do enough fizzicks classes and math classes you can actually calculate what the ideal twist will be for a given projectile at a given velocity. But nobody makes a 1 in 8.73453721 barrel .. so there is actually a fairly decent range of twist rates that can stabilize a particular bullet in a given range of velocity. In reality, it comes down to "there is a minimum" and then the maximum is when your bullets don't make it past the 50 yard line 'cause they've spun themselves apart (yes, this happens with light varmint bullets in the larger cased 22 and under caliber varmint guns, especially if they have a faster twist). This is why when developing subsonic rifle loads you get teh velocity right first and check for any signs of keyholeing in the targets before you risk putting a suppressor and associated tax stamp on the end of the barrel and why you don't drive 35gr .224" hollow points at 4500fps out of your 224 Valkyrie with a 1:7 twist.

A round ball won't spin itself apart but a sphere has some weird physics about it as it flies and gets rotational velocity going, so you want a minimal spin if any. 1:22 is at the bottom end of what is needed for big 458 diameter bullets (500gr 458WinMag) but 1:14 is ideal, drop that bullet length by going down to 300-400gr 50 or 54 caliber (or 300gr 45cal) and you quickly get down to a length where a 1:48 twist will actually stabilize it. Perhaps not as ideally as a 1:36 etc (my 1963 Ruger 44 carbine is 1:38) but it will work and work for RB for the most part as well.

 

[deermanok]

I've shot round balls in my CVA Optima pistol, I think it's a 1/28 twist barrel.
60 grains volume of 3f Swiss black powder.
They actually shot surprisingly well out to 50 yards.

 

[drpatton]

I understand what you are conveying about bore size and rifling twist. I reckon that's why the Traditions .32 has a 1:48" twist but still suppose to be a very accurate RB rifle. I am, however, still curious as to why some of the smaller caliber KY and TN style long rifles have 1:66" twist.

I did try different patches and thickness. Also, different size round balls from 490" to 495". To tell you the truth, its been so many years since I've tried to shoot a RB I have forgotten whether I tried backing down the charge. Sounds like a good thing to try though.

Patched soft lead can and will rip/skip//trip through the rifling with moderate to heavy charges. That's why the original .50 & .53 Hawken rifles with a 1:48 twist had a .012" groove depth. If backing off on your load works, then, more than likely, the PRBs were probably starting to skip through the rifling. The answer to how to use a hotter charge is, use a harder lead alloy or a barrel with deeper rifling.

Edit: I forgot to mention, a slower twist also assist your effort. The idea is to keep the lead, patched or otherwise, in the grooves. There are several variables to make that work. Harder lead, slower twist or deeper grooves.

 

[Okie Hog]

Soon after getting back into muzzleloading in 2000 i began firing round balls in inline and conventional muzzleloaders. i've fired round balls very accurately from rifles with twist rates as fast as 1:32. My old CVA Stag Horn with it's deeper rifling is very accurate with 70 grains of powder and a patched round ball. The .54 Fire Hawk with 1:38 twist rate is very accurate with 80-90 grains of Black MZ powder and a tight fitting patch: At 100 grains accuracy begins to decline.

My .54 caliber Navy Arms Hawken barrel done by Mr. Hoyt has rounded groove rifling and 1:66 twist rate. It makes one 5 shot hole at 50 yards.

The compromise thing with the TC guns is the shallow rifling accompdation for conical bullets. Patched round balls can be accurately fired from those guns, but a tight fitting patch is necessary for use with larger powder loads.

There is this thing about very slow twist rates: Balls driven by different charges of powder land in the same group.

Here's Doc White:

http://whitemuzzleloading.com/round-balls-in-fast-twist-rifles/

 

[ETipp]

Soon after getting back into muzzleloading in 2000 i began firing round balls in inline and conventional muzzleloaders. i've fired round balls very accurately from rifles with twist rates as fast as 1:32. My old CVA Stag Horn with it's deeper rifling is very accurate with 70 grains of powder and a patched round ball. The .54 Fire Hawk with 1:38 twist rate is very accurate with 80-90 grains of Black MZ powder and a tight fitting patch: At 100 grains accuracy begins to decline.

My .54 caliber Navy Arms Hawken barrel done by Mr. Hoyt has rounded groove rifling and 1:66 twist rate. It makes one 5 shot hole at 50 yards.

The compromise thing with the TC guns is the shallow rifling accompdation for conical bullets. Patched round balls can be accurately fired from those guns, but a tight fitting patch is necessary for use with larger powder loads.

There is this thing about very slow twist rates: Balls driven by different charges of powder land in the same group.

Here's Doc White:

http://whitemuzzleloading.com/round-balls-in-fast-twist-rifles/

That's some good information for sure by White.

 

[retrieverman]

Glad I found this thread, because I‘ve been thinking about trying round balls out of my MK85. Texas muzzleloader season starts on Jan 2nd, and I may try to kill a doe with the combo.

 

[deermanok]

I've shot round ball in my Optima pistol. 60 grains [V] of 3f Swiss. With either a .010 or .015 cotton patch, can't remember exactly witch one but the combination was surprisingly accurate out to 50 yards.
At typical bow ranges, I'm sure it would be deadly on deer.

 

[Ka'imiloa]

Soon after getting back into muzzleloading in 2000 i began firing round balls in inline and conventional muzzleloaders. i've fired round balls very accurately from rifles with twist rates as fast as 1:32. My old CVA Stag Horn with it's deeper rifling is very accurate with 70 grains of powder and a patched round ball. The .54 Fire Hawk with 1:38 twist rate is very accurate with 80-90 grains of Black MZ powder and a tight fitting patch: At 100 grains accuracy begins to decline.

My .54 caliber Navy Arms Hawken barrel done by Mr. Hoyt has rounded groove rifling and 1:66 twist rate. It makes one 5 shot hole at 50 yards.

The compromise thing with the TC guns is the shallow rifling accompdation for conical bullets. Patched round balls can be accurately fired from those guns, but a tight fitting patch is necessary for use with larger powder loads.

There is this thing about very slow twist rates: Balls driven by different charges of powder land in the same group.

Here's Doc White:

http://whitemuzzleloading.com/round-balls-in-fast-twist-rifles/

Maybe 10-12 years ago a friend experimented with round balls in his Knight inline rifle (50 cal.). Think it was 1:28 twist. A good strong patch was used, "pocket drill" cloth, creating a pretty tight fit of patched ball in barrel. You always want to avoid burned or holed patches, because gas-jetting destroys accuracy as the ball exits the muzzle. He could shoot loads up to 100 gr. vol. (probably BP but maybe it was Pyrodex R). before accuracy began to fall off.
If he had put a felt wad beneath the patched ball I suspect he could have used 110 or even 120 gr. powder by vol. The wad blocks the burning or holes in the patch.
But the other problem with round ball in an inline rifle is that these modern barrels may have very shallow rifling, and as velocity increases it becomes more and more difficult for the narrow "ring" of tight patch to hold onto the circumference of the round ball and get it to spin adequately. If a ball "strips" the rifling during its path out the barrel, accuracy goes away. It becomes a bit like shooting a roundball in a smoothbore barrel.
Aloha, Ka'imiloa

 

[drpatton]

Maybe 10-12 years ago a friend experimented with round balls in his Knight inline rifle (50 cal.). Think it was 1:28 twist. A good strong patch was used, "pocket drill" cloth, creating a pretty tight fit of patched ball in barrel. You always want to avoid burned or holed patches, because gas-jetting destroys accuracy as the ball exits the muzzle. He could shoot loads up to 100 gr. vol. (probably BP but maybe it was Pyrodex R). before accuracy began to fall off.
If he had put a felt wad beneath the patched ball I suspect he could have used 110 or even 120 gr. powder by vol. The wad blocks the burning or holes in the patch.
But the other problem with round ball in an inline rifle is that these modern barrels may have very shallow rifling, and as velocity increases it becomes more and more difficult for the narrow "ring" of tight patch to hold onto the circumference of the round ball and get it to spin adequately. If a ball "strips" the rifling during its path out the barrel, accuracy goes away. It becomes a bit like shooting a roundball in a smoothbore barrel.
Aloha, Ka'imiloa

I bought a Traditions "PA Pellet Ultralight" .50 Flintlock, with the idea of shooting lead conicals instead of sabots. Because the 1:28 rifling is so shallow, I have to make sure I have enough bearing surface of the lead engaged in the grooves. The increased surface area should keep the bullet in the rifling. This means I need a longer bullet with shorter grease grooves or a paper patched bullet.

I won't be able to test my theory for an other Month or two, due to hunting and weather conditions. I'm very curious how this will pan out. Any guesses?

 

[Buttonbuck]

I’d be interested in this in terms of using round balls in inlines for the 4h shooting sports bc of the required 60 grain max charge. Our spin club is talking about adding black powder. It is just easier to get inlines for the kids as opposed to say a 1 in 66 Hawken

 

[drpatton]

I’d be interested in this in terms of using round balls in inlines for the 4h shooting sports bc of the required 60 grain max charge. Our spin club is talking about adding black powder. It is just easier to get inlines for the kids as opposed to say a 1 in 66 Hawken

Does anyone make an inline with a 1:48 twist rate or a groove depth of .005 or greater? That may work. Most inlines, from what I have read, have twist rates of 1:28 and quicker and groove depths of .003" to .004".

I really do not believe you are going to be able to consistently, shoot round balls through an inline with a twist rate of 1:28 or faster. My understanding is the rifling is too quick and shallow. It may be possible to use a harder alloy. With a groove depth of about .003" - .004", and a thin RB patch of .010, the rifling may not engage the lead ball.

Try a hard alloy, a ball which is a few thousandths under the groove depth, a wool patch over the powder, a well lubed ball patch of .005 (I have never heard of one so thin) and a very low powder charge. This may work? There is absolutely nothing wrong with experimenting, as long as it is done safely. You don't want the ball so tight, it creates a barrel obstruction and acts as a barrel plug, so you effectively have a pipe bomb.

I am going to experiment with a conical in the shallow grooves, so perhaps we can share data from our investigations.

 

[Ka'imiloa]

Does anyone make an inline with a 1:48 twist rate or a groove depth of .005 or greater? That may work. Most inlines, from what I have read, have twist rates of 1:28 and quicker and groove depths of .003" to .004".

I really do not believe you are going to be able to consistently, shoot round balls through an inline with a twist rate of 1:28 or faster. My understanding is the rifling is too quick and shallow. It may be possible to use a harder alloy. With a groove depth of about .003" - .004", and a thin RB patch of .010, the rifling may not engage the lead ball.

Try a hard alloy, a ball which is a few thousandths under the groove depth, a wool patch over the powder, a well lubed ball patch of .005 (I have never heard of one so thin) and a very low powder charge. This may work? There is absolutely nothing wrong with experimenting, as long as it is done safely. You don't want the ball so tight, it creates a barrel obstruction and acts as a barrel plug, so you effectively have a pipe bomb.

I am going to experiment with a conical in the shallow grooves, so perhaps we can share data from our investigations.

With the greatest respect, please see reply #16, a few places up on this thread. The two friends who conducted the inline experiment were both highly experienced ML shooters, and straight-talking, reliable people. If not for that, I would have had a hard time believing what their trial with roundball shooting in a fast twist, doubtless shallow-rifled inline barrel, showed. Yep, they could shoot accurately using patched roundball up to a 100 gr. by volume powder charge. I was amazed!
For shooters like this, they would have known to use a pure lead ball for maximum "grab" of the patch on the circumference of the ball, and to obtain obturation of the ball diameter as the power charge increased. They also selected a very strong patch material, "pocket drill", which is made to line pants-pockets and not give way from keys, pens, etc. in the pocket. Pocket drill is about .010 thick when compressed, as I recall.
In all truth, there is no way you are going to blow up a ML using a tightly patched ball, and indeed, long ago when barrels were significantly less strong, the loading method was to actually hammer the ball down the barrel! In another thread on this Forum, I explained about this, and how even a short-started ball is not going to blow it up either, tho anything atop the powder charge, such as a wad, can drive forward against such an item in the bore, an possibly create a "ring" in the bore there even tho the ball or bullet fires on out.
Of note: a round ball is the lightest possible projectile that can be used in a ML barrel with any accuracy at all, and because it has the least mass, it is also going to produce the least pressure from the firing of the powder. Further, a round ball has the least contact with the barrel, since only its perimeter as a single ring is contacting the lands and grooves. Hence it has the least friction in the barrel of any projectile, and again this means there is less pressure created by any given powder charge.
I do agree that an inline with deeper rifling should work better is shooting roundballs. Nonetheless, the 4H shooting with no more than 60 gr. powder, is likely to work, using a snugly patched pure lead ball, even in a 1:28 twist inline barrel. The usual caveat, mark the ramrod, always applies!
Aloha, Ka'imiloa