Ideal revolver twist

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  • Last Post 29 November 2016
cove posted this 08 October 2016

Just for fun, I want to buy a Remington style black powder 36 cal. revolver and shoot a wad cutter cast from a custom mold.  I envision the bullet to be 0.5 to 0.6 inches long and shot at target velocities.  38 specials have a twist rate of around 181/2 and shoot well.  Most BP revolvers have a twist rate of 30 which is suitable for balls.  Dixie Gun Works lists a Remington Navy with a twist rate of 18.  My question is: which twist rate is best for a wadcutter and or conical bullet? Cove 

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onondaga posted this 09 October 2016

The bullets that load well into BP revolvers are heeled bullets with a short bearing surface and a substantial heel under band diameter to start the bullet. A wad-cutter will have a long bearing area in comparison and if it is NOT heeled it will be very difficult to load  straight into the chambers. You have more considerations than twist selecting a bullet for BP revolvers. The old and valid rule of thumb for BP revolver bullets is that the bullet that is closest to the weight of a round ball will shoot better than a heavier one is pretty sensible.

Heeled bullets also shoot more accurately with a wad. So, a short bullet is important for 2 reasons.

Consider this SWC mold , it can be ordered to your specification diameter and cut with a heel for BP revolver loading and a nose shortened to flat:

http://www.accuratemolds.com/bullet_detail.php?bullet=37-100N-D.png>http://www.accuratemolds.com/bulletdetail.php?bullet=37-100N-D.png

A heeled tumble lube design wadcutter would also be a good selection. Accurate will make molds to your design and weight for a specific alloy.....pure lead is the best choice for BP revolvers.

Gary

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cove posted this 11 October 2016

Gary- Thanks for your input. Will look up 37100N.  I see your point, but isn't the reason BP revolvers have 1 in 30 twist is the fact that a round ball is short and easy to stabilize.  Using the twist formula for BP in Joe Brennans book,  it appears that a 1 in 30 twist will stabilize a bullet around 1/2 inch long, but that is for rifles.  Also, if 1 in 30 is adequate, why do they make a revolver with 1 in 18?  I mentioned that this was going to be a "Fun Project", at this point I'm in the confused stage.   I plan on loading using a custom made loading stand and will have the bullet made so that it has a slight taper at the base to help align it at loading.  Thus being the case, bullet length may be limited to room left in the cylinder after powder and wad have been inserted.  To be continued-Cove  

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onondaga posted this 12 October 2016

http://www.castbulletassoc.org/forum/view_user.php?id=5751>cove

Length of barrel is relative to ideal twist in BP revolvers. Faster than book rifle twist in a handgun is normal. You are applying too much theory for a simple firearm. Concentrate with what you can do with what you have. The twist you have works well with a RB or a light bullet.

Yes, room is at a premium in revolver chambers so trying to load more than fits doesn't work and you can't overload/over pressure a BP revolver with BP or substitutes no matter hat you do with lead bullets.. Being stuck with what fits is a good idea for these handguns. You have  the complete charge range from the smallest amount of powder that fires the bullet to the most that will fit. It ain't rocket science.

If you haven't chosen a powder yet Alliant BMZ substitute is the cleanest available and will seriously add to your enjoyment of the pistol more than anything else. Real Black powder is a disgusting mess compared to Alliant BMZ that is easily 20 times cleaner and completely noncorrosive. The residue from shooting BMZ is very slight and is a dry lubricant that does NOT attract moisture from the air.

Shooting real BP will mean strip down frequently and cleaning the cylinder pin or it will lock up at about 18 shots. You don't have that problem with Alliant BMZ.

Pyrodex is a water s**king fowling sludge mess that stops guns functioning compared to BMZ and Pyrodex is about twice as clean as real BP. Get BMZ and enjoy shooting!

Gary

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Ken Campbell Iowa posted this 12 October 2016

hmmm ... i seldom do black powder but i recall one reason for slow twist is to make pushing the ” ball ” down the barrel ...especially when fouled ... less effortful ...

any validity to that ??

ken

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4570sharps posted this 16 October 2016

36 caliber bullets are .375 diameter! Good luck shooting .358 from the cap and ball revolver!

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Brodie posted this 16 October 2016

36 cal. Cap and ball revolvers use a .375 diameter ball so that the ball will shave lead all around when being loaded.  It is this way to help prevent cross-fires; a most disturbing event if you have ever had it happen.

Barrels are cut with a very slow twist for round balls, because a fast twist rifling causes them to do funny things kinda like a knuckle ball or a good slider or curve.  I found this out when trying to load them in a .458 Winchester.  I could never get them to shoot well no matter what I did. Brodie

B.E.Brickey

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Maven posted this 17 October 2016

.36cal. cap & ball revolvers frequently require a .375” round ball, but some brands, e.g., Uberti and perhaps others as well, use a .380” ball.  Additionally, the specified RB diameter may also have varied depending on when, i.e., the year,  the gun was produced.

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cove posted this 18 October 2016

Gary, thanks again for the input.  I found your comments on Alliant BMZ very interesting.  I had not heard of it and will start a search to come up with a source.  There was also some confusion as to the size of bullet I intend to use. It will be .375 or the correct size for the cylinder/bore. The comments on slow twist being more ameniable to fowling was also interesting.  By using BMZ and keeping barrel clean a 1-18 twist may be the better choice.  Cove 

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rodwha posted this 27 November 2016

I have to disagree, as would modern pistol manufacturers. Look at the twist rates they use compared to the lengths of the projectiles used. The manufacturers didn't just blindly choose a twist rate...

And weight isn't the deciding factor, but length and speed. To suggest weight is, well, untrue to be nice.

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Ed Harris posted this 27 November 2016

S&W .38 Special barrels are 18-3/4” twist and stabilize 1/2” long, 148-grain HBWC bullets well at 700 fps and above. The .38 Long Colt used a 148-grain heeled bullet with .375” driving band ahead of the case and .360” diameter heel inside the case. A similar heeled bullet like Accurate 36-145C, having ample lube capacity for black powder, but made with its with base band of diameter to allow snug finger starting in the cylinder and the nose diameter a full .380” to cut a ring of lead in seating like a .36 Maxi-Ball will work fine. Cast bullets 1:40 tin lead.

73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia

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rodwha posted this 27 November 2016

Oh, and the Ruger Old Army, with its faster 1:16” twist borrowed from the Black Hawk, wins quite a bit of the match shoots with a ball.

My 1:16” Pietta Remington New Model Army and Ruger both shoot a .457” ball, as well as my 170 and 195 grn boolits equally well using the same powder charge (30 grns of 3F Olde Eynsford or Triple 7 in the Remington and 35 grns in the Ruger). My 170 grn WFN boolit is a mere .400” long and the 195 grn version is .460” long as I figured the Remington would come with the previous slower twist of 1:30” as they had prior to retooling and I wanted my boolits to be compatible between them both.

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cove posted this 29 November 2016

As usual, any project I get involved in seems to get complicated.  Buts that is the fun and challenge of cast bullets.  As they say, "If it was easy, anybody could do it".  Any way, at this stage of my quest for knowledge it appears from comments you guys have made, that twist may  be not critical.  I have called several suppliers of BP revolvers and twist seems to be an unknown factor.  A fellow at Taylors has been helpful and he contacted Uberti and reported that they said the 1858 Remington Army (44) had a 1 in 18 twist and the 1858 Navy(36) had a 1 in 20 twist.  Again, no one I have talked to has any idea why the twist varies.  After commenting on the standard twist for pistols at around 1 in 181/2, I checked my 38 special that has a Day Arms 1500 barrel and found it had a 1 in 10 twist.  I was surprised and measured it several times to be sure.  It shoots cast  HBWC into less than one inch at 25 yds, and  around two inches at 50yds.  So, since this project is just for fun, I'm going with a 1 in 18 or 20 twist and will let you know the results.        

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