Fast and low twist

[wolkentanz]

Hello all,

is it right that fast twist rifles need a lower powder charge than slow twist ones ?

I have a .36 rifle (Green Mountain barrel) that shoot poor groups with 40 grn 3F Swiss powder. Swiss powder is more powerful than Goex so that this load is equal to 46 grn Goex (15 % more power). The twist is 1:48.

Should I reduce the load ?

Thanks in advance !

 

[roundball]

Hello all,

is it right that fast twist rifles need a lower powder charge than slow twist ones ?

I have a .36 rifle (Green Mountain barrel) that shoot poor groups with 40 grn 3F Swiss powder. Swiss powder is more powerful than Goex so that this load is equal to 46 grn Goex (15 % more power). The twist is 1:48.

Should I reduce the load ?

No...that charge shouldn't be causing accuracy problems at all...what size ball and patch are you using?

 

[paulvallandigham]

I agree with Roundball. The 1:48 should be just right for your 36 caliber rifle. What ball and patch combination are you using? You should be trying a .350 ball, and .015" thick pillow ticking, with a good lube for great accuracy. Most people get by using 30 grains of FFFg Goex BP in that gun. I have loading data up to 60 grains of FFFg powder in the Hodgdon Reloading manual.

Are you burning patches? Swiss powder is hotter, and you should always be checking your spent patches to see what is going on. The higher the powder charge, the more there is a chance that you will be burning the patch. Especially if you are using a patch that is .005, or .010" thick, both of which are way too thin for that load and caliber.

 

[MikeChapin]

I have two .36 rifles. One, a old Hopkins & Allen cheapie, uses 20 grains of 3F for 25 and 50 yards. The other is a long rifle that uses 30 grains of 3F with a .024 patch for 25 and 50 yards and 40 grains for 100 yards.

Years ago I was using .018 ticking for the patch. the 30 grain loads was fine but the 40 grain load would blow the patch to confetti. I was in a match shooting at a small gong at about 70 yards. One of the other competitors saw what was going on and mentioned it. I started putting a bare patch in the barrel before loading the patched ball. This kept the patch around the ball from blowing out. Won that match by the way with the new setup.

Myself, I would drop down ten grains and see what that does. As Paul mentioned, try to recover your patches and see what condition they are in. They will give you an idea of why the gun is shooting poorly.