Twist rate question...

[SCLoyalist]

On another forum there has been discussion of shooting .32 PRB out of a barrel with 1:66 twist.   My first thought was that wasn't a good idea, but after some googling and searching, I've seen references to Douglas barrels in that caliber & twist performing well.   On the other hand, there must be some reason why barrel makers like GM, Rayl, Colerain, Rice, and others consider the 'optimal' twist rates for their RB barrels to get slower as the caliber increases. 

I know this site has some barrel makers and no doubt some closet internal ballisticians lurking.  What are the pros and cons of a slow twist barrel in squirrel gun caliber?


Thanks, SCL

[little joe]

Stood beside a fellow who loved small calibers and on that day he shot a 44 score on a standard NMLRA 6 in  target. Not bad for a 66 in. twist Douglass 32 cal. with open primitive sights

[hanshi]

The ONLY thing I know for sure is that there's no such thing a "over-stabilization".  I will add to that, that accuracy is good bullets going through good barrels and twist be d_____.

[Hungry Horse]

 I feel there are optimum twists for certain calibers, but that doesn't mean that a different twist rate won't work. In small calibers like .40's I think the optimum rate is around 1 in 48". You have to also take powder charge size into consideration. It's going to take more powder to stabilize the bullet in a slow twist barrel. So, do you really want to consume maybe half again as much powder per shot, for a minimal difference in accuracy?  I think the old twist, to caliber,recommendations took into consideration economy, as well as performance.
 I owned an old Jukar .45 cal. pistol, that I used for parades, and survival walks, back in the day. These guns were make from an old piece of rifle barrel, with a 1 in 48" rate of twist. On a survival walk I was (disabled) to the point that I couldn't shoulder a rifle. Knowing I would be making rifle distance shots with a 8" barreled pistol, with a slow twist, long story short, I opted for a rifle size charge. The pistol exceeded all expectations. I shot it with the heavy charge for as long as I owned it.

                                         Hungry Horse

[Dphariss]

On another forum there has been discussion of shooting .32 PRB out of a barrel with 1:66 twist.   My first thought was that wasn't a good idea, but after some googling and searching, I've seen references to Douglas barrels in that caliber & twist performing well.   On the other hand, there must be some reason why barrel makers like GM, Rayl, Colerain, Rice, and others consider the 'optimal' twist rates for their RB barrels to get slower as the caliber increases. 

I know this site has some barrel makers and no doubt some closet internal ballisticians lurking.  What are the pros and cons of a slow twist barrel in squirrel gun caliber?


Thanks, SCL

Cloth patched projectiles are limited by the strength of the patch. This becomes more and more important as the weight of the ball increases. A 69 with a 24" twist will not make much velocity a 32 with a 24 will likely be OK. But 24" is a BULLET twist in both bore dimensions.
Round balls are not very finicky. A 48" will work extremely well to at least 54 caliber even with a heavy loads. But a 66 works good too from 32 to 69 at least.
Slower twists work well 70-72 in 50-54 etc.
All the RB twists in general use work well. Obsessing over the twist rate of the PRB barrel is silly. For a 40 I personally would prefer a 48 (and for 50 too) but its not a deal breaker since 66 has proven to be very accurate in 32.

Dan

[little joe]

Not bad for a 66 in. twist Douglass 32 cal. with open primitive sights

That's a good example of the  testimonials in favor of the slow twist for small calibers I saw.   Don't suppose you remember anything like powder charge he was using, or how he did at longer target distances?

30 grains powder,.313 ball and .016 ticking He was tough that day. Joe

[Don Getz]

I onetime made a 40 cal. barrel for a cross stick shooter, it had a 1/72" twist.    It shot fabulous, but, was shot with
80 grains of FFF powder.   For smaller calibres I would prefer 1/48" twist, or, for that matter, I could live with a 1/48" in
any calibre........Don

[RichG]

in my personal experience a 1-66 twist in a 32 is too slow for the intended use of a 32. It will probably shoot better with 40+ gr. My 32 tenn. with a 1-48 shot best with 25 gr 3f. The t/c cherokee with a 1-30 twist shoots good down to 10grs. Ive also had a couple of 50 cal t/c hawkins (1-48)and both lost accuracy with anything over 90grs. 3f (prb)the smaller the ball the faster the twist. The larger the ball the slower the twist. It's the momentum of the balls rpm's.  It takes more spin to keep a light ball spinning than a heavy ball. Sam Fadala has a very good explanation of this in his books. Very slow twist barrels like Forsythe used require large charges to shoot best witch was their intended purpose. All that being said I've never had a muzzleloader that I couldn't find a load for. It might be more or less than you would like but it can be made to shoot accurately.

[Standing Bear]

Ive also had a couple of 50 cal t/c hawkins (1-48)and both lost accuracy with anything over 90grs. 3f (prb)

I saw the same thing in the TC 1:45 twist .50 cals.  However I now believe it was the shallow rifling rather than the rate of twist that caused PRB accuracy to deterioate with charges >90 gr.  The ball was trying not to rotate and the force of a heavy load caused the patch to strip.  Thus gain twist was born.

Tom Gillman's personal .40 had a 1:66 twist as do mine and all have deep .010 - .013 rifling.  Had a .50 years ago w 1:66 twist and it didn't start shooting well until I got to 90 gr FFg.  Shot 120 gr beautifully.  I had a .50 barrel cut with a 1:56 twist but .012 deep rifling and it works well w PRB  from 60-90 grains as intended.
TC

[willyr]

You know, we can berate the Douglas barrels with their slow twist all we want to, but, the fact is those barrels would really shoot. Max Vickery could hold shooting clinics in his day with a Douglas barrelled .32, 1 in 66 twist. When I first started shooting in the early 1970's, one of my mentors used a Bob Watts .32 flintlock with a Douglas barrel and if you ever beat him on a 100 yard target, either you had an outstanding day or he had a really bad day. Back in those days, we used a .323 ball, .018 patch, and 30 grains fffg at 25 and 50 yards, 50 grains fffg at 100 yds. When I got my first GM .32 barrel, I probably fired 500 shots before I found the load which worked in it. That load turned out to be 35 grains ffg, .323 ball, and .018 patching. The fact is: the only way to really find "THE Load" is to try a lot of different things and do a lot of shooting.
Be Well,
Bill

[Candle Snuffer]

Years ago I had Ed Rayl make me a .40 x 7/8'' x 36'' - 1 in 72 twist w/ round bottom rifling barrel and it shoots great.  This particular barrel handles lite 3fg loads (up to 50 grains) very well, and will handle 2fg loads very well from 45 to 65 grains.  I have even shot 1fg through this barrel with good results.  I will also add that no matter what powder granulation or size of charge, this barrel reloads easily - better then any faster twist square bottom rifled barrel I have ever used, and yes I do use a spit patch.

At the time Ed made this barrel for me, I also had him make a .45 x 7/8'' x 38'' - 1 in 72 twist w/ round bottom rifling barrel which I used to make my neighbor a plains rifle like he requested.  The first three shots from this particular rifle netted a three shot 1 hole group off the bench from 25 yards while using a 45 grain charge of 3fg Goex, and to this day shoots extremely good.

I like the slow twist in small calibers, (at least the .40 & .45) as they have proven to be very accurate.  Sure, the best load(s) still need to be worked up just like any other barrel.  I do wonder if the round bottom rifling has something to do with this?

[2lookindown]

Guys, I started the post on the other site looking for some shooters that used the 1:66 twist...I'm having a barrel made in a 32 cal 1:66 twist... It was originally a 29 cal with a 1:57 twist.... The barrel was left uncleaned and ruined the barrel.... So I went to the 32 cal.... It was built by Rex Maxxie.... Wayne Jenkins has his equipment now.... I have some friends that are shooting the 1:66 twist all the way down to the 29 cal.... They say they are tack drivers... I tried to get some info on the build and the reason for such a faster twist rate was needed for a small ball ... I guess it will work...  I was told buy a few of the builders that the reason for the middle of the road twist (1:48) was to accommodate the conical (fast twist) and the round ball (slow twist) and the would let a shooter shoot either conical or round ball... Maybe I was misinformed and the 32 cal 1:66 twist won't shoot fer snit ? But all of your opinions a helpful....

SCLoyalist, Thanks for digging around and gettin some more info.... Again thanks

[hanshi]

Faster twists were used back in the 18th & early 19th century probably because lighter charges were fired than what today's shooters normally use.   1-66" is NOT a death sentence for a .32.  You may have to load heavier but yes; excellent accuracy can be had.

[2lookindown]

SCLoyalist, sorry to kill your thread.... I guess they don't like a newby over here either... But thanks anyhows...

[Dphariss]

Faster twists were used back in the 18th & early 19th century probably because lighter charges were fired than what today's shooters normally use.   1-66" is NOT a death sentence for a .32.  You may have to load heavier but yes; excellent accuracy can be had.

I believe the concern over twist rates in RB rifles is, except for extreme cases, a tempest in a teapot... But here goes. Again...
It used to be believed, by some not all,  that the ball needed to make one turn in the barrel. This belief resulted in some large bore, short barreled rifles being grossly over twisted. Lots of European  rifles of the mid-18th c had twists in the 26-32" range due to the short barrels often used. Coupled with the larger ball sizes 58 and up this reduced the velocity they could obtain without stripping the patch.
It is likely that the 48" twist that was common for RB rifles of all calibers may have been the result of the "4 ft" barrel common in America from at least the mid-18th c onward.  
That the 4 ft twist is very useful for a wide variety of calibers is self-evident from both historical and modern usage.
If the 58 Minie could be used in a 72" (because its somewhat stabilized by its heavy nose and light skirt) why would a RB care much? I suspect that really good accuracy can be obtained with a 32 cal from 30" or even faster to 72 or slower.  Heavier balls with more rotational inertia need a slower twist to prevent blowing the patch at the point of highest pressure and greatest acceleration. Yet current experience shows that a 66" twist will work with almost any bore size to at least 69 caliber with heavy charges.
When shooting cylindrical bullets or even short conicals twist can be very important. Round ball? It just needs enough spin to make it shoot accurately,  to prevent it "knuckle balling" and slow enough the patch can maintain its integrity. The cloth patched RB also needs rifling in the .008 range or somewhat greater to assure that the patches  can get proper grip but grooves over .012 are just window dressing. It is also necessary that the  patch imprint on the ball at the lands during loading to assure that the two have a good grip on each other. This is easier to do with narrow lands than wide ones.
But in general don't worry about the twist.
If in doubt don't come here to post ASK A BARREL MAKER.... Its a simple concept. Will you find varying answers? Sure. Jim McLemore will not even tell you what his gain is. You take what he makes. I would not question his knowledge.
Jake and Sam Hawken used 48, Bill Large used 56, Douglas used 66, Green Mountain uses 48 for small bores around 60 for mediums and 70 for 50 up. ALL THESE BARRELS WILL OUT SHOOT THE SHOOTER. McLemore's gain will shoot virtually through the same hole with a scope. He tests them all...
Buy the barrel of your choice and find out what it likes.
 
Dan

[PPatch]

Excellent post Dan.

dp

[little joe]

Just read my first reply and I forgot to mention thatthe range was 100 yds. and offhand.

[Frizzen]

You can look up Sharon Smith's records she holds at Friendship. She used a Douglas 1-66 twist 32.
She had a tender shoulder and only used 30 grs. Goex FFF.

[2lookindown]

I hope to get out there to the shoot this year... it aint that far from me ... I just hope my eye holds up long enough to shoot a few shoots ..... I've just got the one eye  and I have sugar  so I hope I can hold it together long enough to win a shoot or 2 with the smoke pole like I have with the shotgun....

[Dphariss]

The ONLY thing I know for sure is that there's no such thing a "over-stabilization".  I will add to that, that accuracy is good bullets going through good barrels and twist be d_____.

Actually there are downsides.  Except as noted in my previous post where RB rifles were sometimes twisted to the point of being useless for their intended use they generally don't apply to the PRB.

Dan

[hanshi]

The ONLY thing I know for sure is that there's no such thing a "over-stabilization".  I will add to that, that accuracy is good bullets going through good barrels and twist be d_____.

Actually there are downsides.  Except as noted in my previous post where RB rifles were sometimes twisted to the point of being useless for their intended use they generally don't apply to the PRB.

Dan

I probably should have added the corollary that "extreme cases are to be ignored" .  Within our concert I think we can all agree on the range of twists and projectiles that beg our attention.

[gumboman]

I know this thread has addressed small bore calibers and twist. Very interesting. My issue is I have a 62 caliber under construction and nearly finished. My custom barrel is mounted to an underhammer action. Problem is I cannot get it to shoot decent groups. My best group so far has been 12 inches at 100 yards.

Here are my barrel specs. 62 caliber 30 inches in length. Twist 1 turn in 90 inches. Lands .040 wide, grooves, .200 wide and .005 deep. This is a form of Forsyth rifling. I have shot loads of 2f Goex from 140 grains to 200 grains. Balls have been both .600 and .610 swaged and cast. Using a 20 gauge wonder wad over powder. Patches have ranged from .010 to .020 thickness with wonder lube.

My sighting system is a Malcom 3x scope of 17 inches.

I have been in this muzzleloader game for 35 years. I have built 6 rifles of various calibers. Shot round balls and conicals of all types. I have hunted and harvested just about every animal that has walked or crawled in the USA. I am a dedicated traditionalist and have owned and shot most type of black powder guns in one form or another. Every gun I have owned grouped well on my first visit to the range. Over time loads were developed to fine tune the accuracy with fantastic results.

But this barrel has me bamboozled. Up until this time my round ball barrels have had a 1-72 twist. The only exception is my first flintlock purchased from Dixie Gun Works in 1982. Its barrels is of cheap design, has a 1-56 twist but shoots 50 caliber balls like a dream. I cannot understand why this custom barrel won't shoot.

This gun was intended to be a large bore, long range hunting weapon. I have a considerable amount of money invested in this new gun but I would not shoot any animal past 50 yards.

I am seeking advice from others wiser than me on large bore, slow twist round ball barrels. Just wondering what I am missing. Would like to know if there is anything else I  can try to get this barrel to group. If I cannot figure out a solution all I am left with is to scrap the barrel and buy something new. But considering I have more than $400 in this barrel at this point I would rather not do that.

[Standing Bear]

Gumbo, I agree, step one is to insure the scope and it's mounting are solid.  I know first hand the woes of a loose receiver sight.

If the sighting system is solid then on to the load and finally the barrel itself. 

What do the patches look like?  Also, load a ball then blow it out with CO2 or a light charge.  Is the ball engraved (land and groove) and patch still in good shape?  I believe the .005 rifling maybe too shallow for 325+gr round balls and charges as stout as you are using. 

Good luck.
TC

[gumboman]

Many thanks for the pointers. This barrel is actually the second barrel for this project. The first barrel shot worse. Rifling twist was 1:104 with knife edge wide lands. I estimated the lands to be .015 wide on the first barrel. The barrel maker made a second barrel with rifling to my specs which is the one I am now working on.

I did try a peep sight with blade front sight and got same results. The patches look good. No burn out. Only slightly tattered edges and only a hint of cuts from the rifling. But I would expect some slight cuts from new rifling.

I have rammed a ball and patch down bore then pulled it with my loading rod. Inspection showed patch crosshatch pattern imprinted into the ball so this indicates engraving. TC I am thinking like you. Shallow grooves in combination with the slow twist is the problem. So far Forsyth rifling has not proven to be as claimed by some. At least that has been my experience so far.

In terms of the barrel maker, he has demonstrated concerned so far. Made the second barrel without question. My sense is that he has little to no experience with Forsyth rifling personally. He did test shoot the barrel. He sent a picture of the target. At 55 yards the group was 6 inches. He thought I would be happy after working up a load but so far the groups I have gotten are approximately equal to a smooth bore.

Currently I am rereading some of my old muzzleloading books and manuals, scouring them for hints about what to do. This gun project should have long been completed but the fact that I cannot get the gun to shoot decent groups has made for a protracted project. I am beginning to loose enthusiasm.

[hlary]

http://www.leverguns.com/articles/wosika.htm

anyone seen or read this before? It's an interesting read and address primarily the twist rate per caliber and charge/muzzle velocity for long distance accuracy. Also leaves some questions unanswered.