04 November 2010
Thanks for the tips, I'll have to take a close look at the throat and bore when I get the rifle.... I'm curious about the accuracy you mentioned, I've got a .32 rimfire falling block that will do very nice cloverleafs at 50 yards with my dwindling supply of 1970's vintage Cannuck ammo. When my ammo runs out, I'm planning to convert it, or have it converted, to CF and chambered for .32 S&W long.
Do you suspect that RF will become less accurate with the conversion?... I Not to say that the guns aren't accurate enough, but I wonder if they could be more so with a slower twist?...Correct me if I'm wrong, but I believe the old standard for 32-20 was 1 in 18 and later was updated by some manufacturers to 1 in 16.
I'm not sure it is as much a matter of twist rate, but of bullet quality and proper fit. The quality of swaged bullets in rimfire ammo is very good, better in terms of dimensional uniformity and roundness than typical cast pistol bullets. They are also soft, seal the bore well, are well lubricated, and used in light, low pressure loads with fast burning powder. I have tried to maintain those parameters in my bunnygun loads and have done best when I did.
As for twist, I have shot .32 bunnyguns in twists from 10 inches all the way to 20 inches and almost everywhere in between. Accuracy with light bullets and loads was not materially different, however, the faster twists let you shoot very light loads with heavier bullets.
In .32-20 revolvers I have encountered twists of both 16 inches and 18 inches, and in handgun use, based on my experience with the .32 S&W Long the faster twist is better. My most accurate .32 revolvers have been a Colt Officer's Model Target in .32 NP which had a 14 inch twist, and a custom S&W K32 I had built recylindernbg and rebarreling a .38 Special, which used a 14 inch twist Obermeyer tight-bore .298x.308 Palma barrel.
In .32-20 rifles the most common twist is 20 inches, which is used in the Savage Model 23 boltguns, 219 single-shot, and the Winchester 92. A 20 inch twist was also used in the Winchester .32 self-loading and the .30 M1 carbine. In a rifle I would worry less about twist than in getting a good quality barrel, cutting a good chamber in it and casting match quality bullets that fit.
The most accurate .32 S&W Long rifle I ever shot was a Remington Model 788 which Ellis Lea had, which had an 10-inch twist Hart barrel on it and long, gradual Ardito-style throat, in which he used the Saeco #315 breech-seated with a compressed charge of RL-7, about 8 grains, and Federal 205M primers. This rig drove bugholes at 100 yards and had the same trajectory as a .22 match rifle. Velocity was subsonic.
Using handgun ammunition it shot no better than I am getting. You have to decide whether you want a bunnygun which is a fun plinker with ordinary loads, or if you want something so specialized that it isn't suitable for hunting, and requires tweaked ammo which you cannot use in your revolver. I think that defeats the purpose.
73 de KE4SKY In Home Mix We Trust From the Home of Ed's Red in "Almost Heaven" West Virginia