1/66 twist

[Dan Jordan]

simple questions for you experts.Can u shoot any other bullet in 1/66 twist or is strickly RB? :hmm:

 

[LRB]

Pretty much a RB twist, but you can try others.

 

[D Sanders]

Pretty much what Wick Ellerbe said. What caliber is it?

 

[nkbj]

In .54 the old Lyman heavy skirted minie can shoot if you push it hard enough to seal the bore. The design is a little shy on lube grooves though so you can run into leading. And if you don't push it hard enough to seal off the deep rifling you can get gas cutting and really get some leading.
The Lee REAL might work for you and it has bigger lube grooves and will work with card wads (there's no hollow base) to prevent gas cutting.

 

[BrownBear]

simple questions for you experts.Can u shoot any other bullet in 1/66 twist or is strickly RB? :hmm:

I was in a "prove it to me" frame of mind when I got my first GPR, so I tried just about every conical known to man. The shorter and lighter the conical the better the group you can get with it at 25 and 50 yards, but you have to drive them really fast to do so. I managed "hunting" accuracy groups around 4" at 50 yards with the shortest and max charges. But move out to 100 yards with the same load, and I couldn't keep three shots on a 15" target paper. It appears that as they slowed down past 50 yard, the conicals really started to wander.

Bottom line, I contributed to the profit margin of the bullet and powder makers, but I didn't come up with anything I'd hunt with.

 

[mooman76]

1/66 is kind of slow for a conical but it also depends on the caliber and length of conical.

 

[Dan Jordan]

its a 50 cal.

 

[George]

According to the Greenhill formula for calculating the spin required for a given bullet length or, conversely, length of bullet which can be stabilized by a given twist, a twist of 1:66 will work for bullets .568" long or shorter in a .50 caliber.

Spence

 

[nkbj]

That's way slow for a conical in a fifty. Anybody tried one? I haven't in the GPR fifty barrel.

 

[nkbj]

But wait... this might actually work.

This is a Lee REAL in the .50 GPR barrel. The rear ring is .499" and a metal to metal fit on the bore. The lowest ring visible in the picture is .503" diameter.


The Greenhill Formula calculator for a .50 bullet and .53" length gives a minimum 70" twist. And the REAL would be shorter and fatter when it came out of the barrel.

 

[bubba.50]

i used both weights of lee r.e.a.l. bullets in my 54cal great plains with good results. accuracy wasn't much different than prb. would have killed anything at any yardage i'd shoot at.

 

[gmww]

simple questions for you experts.Can u shoot any other bullet in 1/66 twist or is strickly RB? :hmm:

For what it's worth. I've had good luck with maxi balls in my slow twist ML. I did notice a slight oblong hole in the paper but they held a very good group 4" at 100 yrds. Oblong being you hand to really look carefully to see it. Not to be confused with key hole.

 

[nkbj]

And don't forget double ball loading at "muzzleloader range".

 

[Spikebuck]

I very successfully shot several different conicals from slow-twist barrels, though they both have shallow, square grooves. My Pedersoli Rocky Mountain Hawken with 1-65 twist in 54 cal shoots Hornady Great Plains 435 gr conicals very well with perfectly round holes cut into the target at 100 yards. My Pedersoli Frontier in .54 could shoot the GP conicals or the short Buffalo Ball-ets very well. Neither of them liked the TC Hunters. So net, you'd have to experiment to see if your gun would shoot any given conical well.

The Hornady PA Conical in 50 is a short conical that might have potential.
http://www.hornady.com/store/50-Cal-240-gr-PA-Conical/

 

[George T.]

This is not meant to be a cop out but after research get a few and try them It would seem to me that you will have to shoot a pretty stiff powder charge. The proof will be in the shooting. I found the information interesting that as they slow down the groups spread! Geo. T.

 

[larry wv]

I have a .50 cal CVA 1 in 66 it will hold a 5 inch group at 100 yards with a maxi ball and 90 grs 3f. But it is unstable as far as tracking through a Deer at long ranges. Larry

 

[Rat Trapper]

For best accuarcy in any of my TC Hawken rifle using conicals required pretty heavy charges. Those rifle have a 1-48 twist, so not sure if you could get a conical to shoot or not out of a 1-66.
Round Ball did pretty well with a Lee conical out of his 40 cal with deep groves, but the rest of us didn't?

 

[nkbj]

I'm still working with the GM slow twist .40's trying to come up with a dependable conical technique, as in one that works almost every time instead of works most of the time. Best results so far are with a .41Colt mold but it was really too small in diameter.
What works:
Paper patched and sized down to be thumb tight to the bore (0.403").
1/2" long bearing length.
Long nose.
Large groove towards the rear.
Over powder card.

The rather large bore diameter on the GM barrels may make it easier, seeing as most available molds won't have to be squeezed down so much.
Muzzleloading is just a tinkerers paradise.

 

[Swede50]

I put 5 54cal Real Boolits in one ragged hole at 25 yards with 100 grs of Geox fff off the bench rest one day using my Precussion Lyman GPR.
I have no idea how they will shoot at 100 yrds.

My 50cal TC Flint lock does not like REAL boolits they are too tight.

 

[nchawkeye]

There is more to it than the twist...

Is this a true round ball barrel with the deeper cut rifling or a production barrel with the more shallow button rifling???