Fudging on the twist rule of thumb

[gmww]

I've put together a 30",1:60" twist barrel for my Underhammer. The idea was to use it hunting. I know the general rule is it is a RB twist. Being one that often pushes the limits I've been shooting Maxi-balls out of this twist. It is a .50 cal by the way.

I can tell I'm at the envelope cause I'm getting slightly off center holes. However I'm also getting 1-1.5" groups at 50 yrds. and good groups at 80 yrds. My groups at 100 yrds is about 4-5". The off center holes continue but don't seem to be any greater in size from 50-100 yards.

At any rate I'm going to use this for hunting this season.

:hatsoff:

 

[swquiro]

Supposedly the shorter conicals will shoot decently out of SOME slow twist barrels. Looks like yours is one of them. Alter your sights a bit and you are good to go.

 

[Lone Carabiner]

Plenty accurate for woods hunting but did you try dropping the powder charge some? May help 'keyholing'

 

[gmww]

The sights I'm currently using are peep sights. The powder charge has been played with and the key holing has been consistant throught out. Actually the key holing is very minute. It resembles a double strike at first glance in the same hole. I'm finding the best accuracy for the .50 has been between 95-100 grns. of Geox BP 2F.

:thumbsup:

 

[roundball]

I've put together a 30",1:60" twist barrel for my Underhammer. The idea was to use it hunting. I know the general rule is it is a RB twist. Being one that often pushes the limits I've been shooting Maxi-balls out of this twist. It is a .50 cal by the way.

I can tell I'm at the envelope cause I'm getting slightly off center holes. However I'm also getting 1-1.5" groups at 50 yrds. and good groups at 80 yrds. My groups at 100 yrds is about 4-5". The off center holes continue but don't seem to be any greater in size from 50-100 yards.

At any rate I'm going to use this for hunting this season.

:hatsoff:

:bow: dare to be different...I love it !!
:thumbsup:

 

[WV_Hillbilly]

FWIW...
I have noticed that typically "slow twist", "round ball barrels" shoot more accurately with conicals--than "fast twist, "conical barrels" shoot accurately with round balls.

This applies more to larger caliber guns (.50cal or bigger) also. I suspected that this phenomenon was true, as a rule; as there are many Civil War era rifled muskets which have "slower twists" and yet accurately shoot relatively long conicals with reasonably light powder charges.

Does anyone else subscribe to the above? or is this some kind of delusion I have fallen under?

Regards, and shoot safely!
WV_Hillbilly

 

[faw3]

The same here Hillbilly, for years (cause I was in a wheelchair) I just didnt want to fool with RBs so shot max/mins out of every barrel, the larger the bore the more forgiveing the grp. I could get decent fast twist RBs grps if I kept the powder way down. Now that Im not in thatthing anymore i shoot nothing but RBs :rotf: Its a strange world. Fred :hatsoff:

 

[renovato]

I know there are more differences in the guns than just rifling twist, but I have an Investarms .54 Hawken with 1:48 and a GPR .54 1:66. The Investarms shoots a ball more accurately than the GPR, though they're pretty close. I wish the Hawken was 1:66.

 

[arquebus]

Have you considered trying a .50 caliber minie (hollowbase) mould? That 1:60" twist should stabilize it just fine. I shoot alot of Rifle-Muskets which usually have 1:66"-1:72" twists & they were designed for Minies.