What twist would be right for roundball in a 40 caliber ?

[kelljp]

Went through the shop and gathered all the Senaca and Cherokee parts I had replaced on several rifles last year for one reason or another. Looks like I can assemble a complete rifle with them. Like I said they are functional but might have a defect that was easier to fix with a replacement part. The barrel is a 45 caliber Cherokee, I'm thinking of sending it to Bobby Hoyt for relining it to a 40 caliber. What would be a good twist for roundball in that short barrel ?

 

[FishDFly]

Why not trust Mr. Hoyt?

 

[kelljp]

Why not trust Mr. Hoyt?

Good point, I was under the impression he might ask my preference as he probably has many options he can offer.

 

[Uncle Miltie]

A 1/48" twist will work very well.

 

[Boomerang]

Yep, I would see what he suggests. I'm thinking around a 1 in 48".

 

[Dusty_Traveler]

I, too, will suggest 1:48.

 

[longcruise]

Why not trust Mr. Hoyt?

That's what I did. They all shoot so well I never bothered to check the twist in any of them. Still don't know what they are!

 

[BillyC]

This might be a dumb question but here goes, does caliber have any bearing on what the twist rate should be for round ball? I assumed that round ball needed a very slow rate, like 1 in 60 or so but seeing a recommendation of 1 in 48 has me a bit confused.

 

[kelljp]

Tends to get more confusing the more you read. 1:60 to 1:70 seems to be sold as a roundball twist. But that discussion is normally in reference to 50 or 54 caliber rifles. Usually the advertised barrels are in the 30-32 inch length.
I guess my original question should have been does going to the shorter (Cherokee) barrel impact that ?
But 1:48 appears to be the general consensus.

 

[LME]

I thought a 1:48 twist was so you could shoot ball and conical? If he wants to shoot balls only a slower twist may give him a few more F.P.S.?

 

[64Springer]

1:60 or slower.

 

[#BPBReloadingFFL]

1:56 will work

1:70 will not

 

[Ohio Rusty]

My .40 is 1 in 66.
Ohio Rusty ><>

 

[ORBushman]

Man, I know even less than most! How does one go down in caliber? I can see going up from .45 to .50 but, how do you go down to a smaller caliber if the barrel is already bored to 45?

Apologies to the OP for the thread drift!

 

[BillyC]

Man, I know even less than most! How does one go down in caliber? I can see going up from .45 to .50 but, how do you go down to a smaller caliber if the barrel is already bored to 45?

Apologies to the OP for the thread drift!

Bore out bigger then insert a sleeve that fits the new bore and is .45 caliber

 

[ORBushman]

Bore out bigger then insert a sleeve that fits the new bore and is .45 caliber

Thanks, that's something I hadn't heard of.

 

[Grenadier1758]

Went through the shop and gathered all the Senaca and Cherokee parts I had replaced on several rifles last year for one reason or another. Looks like I can assemble a complete rifle with them. Like I said they are functional but might have a defect that was easier to fix with a replacement part. The barrel is a 45 caliber Cherokee, I'm thinking of sending it to Bobby Hoyt for relining it to a 40 caliber. What would be a good twist for roundball in that short barrel ?

I would recommend asking Bobby Hoyt for his recommendations.

This is not a question that comes with a single answer. What the optimal twist for a given caliber is based on several factors. Of course, caliber is the starting point. Next comes the projectile, round ball or conical bullet. What is the purpose of the rifle? Short range will work better with a faster twist and lower powder charge. Depth of the grooves and patches to fill the grooves add to the stability of either a patched round ball or a conical bullet. Radius bottom grooves or square bottom grooves have advocates for both shooting round ball or conical balls. The conical bullets seem to work better in shallow square bottom grooves. Patched round balls work well in either configuration. The width of the lands should be narrower than the grooves. We want the patch to have room to fit into the grooves. The number of lands and grooves seem to reside in the 6 to 8 lands. Some swear by the 7 lands and grooves based on the theory that having the land opposite the groove makes for a better fit. (Maybe?)

With all that said, most rifle barrel makers offer a standard 40 caliber with a twist rate of 1 in 48. However, other twists rates can be custom ordered. Bobby will most likely offer a liner with 1 in 48 twist and radiused grooves.

 

[longcruise]

I guess my original question should have been does going to the shorter (Cherokee) barrel impact that ?

The question of twist vs barrel length seems to come up only rarely. Barrel makers who make pistol barrels seem to settle on faster rates in the 1:25 or so range. But I don't think that would be a concern in any rifle length barrel.

Just my opinion but I think that twist rate gets overthought. I've shot 110 grains of 2f in a 54 with 1:48 twist with good accuracy. It's surprising what can be discovered if you ignore the "rules".

 

[DementedMindOfJac]

Went through the shop and gathered all the Senaca and Cherokee parts I had replaced on several rifles last year for one reason or another. Looks like I can assemble a complete rifle with them. Like I said they are functional but might have a defect that was easier to fix with a replacement part. The barrel is a 45 caliber Cherokee, I'm thinking of sending it to Bobby Hoyt for relining it to a 40 caliber. What would be a good twist for roundball in that short barrel ?

It's not about the length of barrel. It's a combination of bullet bearing surface and velocity. With RB, the surface that interacts with the rifling is very small so it needs a slower ROT. 1:72 to 1:48, though 1:48 is more an intermediary for RB and conical. With a ROT like say 1:20, a RB won't "grip" the rifling properly and just strip through

Hope that helps.

 

[nkbj]

Having 16" and 48" I'd probably end up with an average in between.