General discussion > Black Powder Shooting
Gain Twist
Daryl:
--- Quote from: Tim May on January 07, 2022, 09:55:25 PM ---Thanks for all replies. Just undisighted
What to with this barrel it is marked
J.J.J.J.
Large. No other stampings
Tapered 1and 1/8 to 1 in. 45 cal.
36 in long gain twist.
Thanks
Tim
--- End quote ---
The .58 Large Barrel I had, was choked for sure but did not have a gain twist.
Are you sure it's got a gain twist?
WadePatton:
Here's what I got sorted in my head the last time, or maybe the other last time we discussed "gain twist": That rifling is/was rarely perfectly cut such that there is "zero" gain from one end to the other. That it may vary to gain a little bit here and lose a little bit there, and what we measure is actually an average of those variations. But that if the muzzle it cut where the gain is negative, reduced accuracy is the usual result. And thus intentionally using a gaining rate of twist when rifling a barrel should always give a positive gain at the muzzle, avoided the accuracy loss inherent to a negative gain.
I left out some details for "brevity", but I retell this because when I first heard of gain twist, this wasn't how it was explained. Makes a great deal of sense to me now, but I don't know how much more accurate modern machining is than the old ways. Perhaps enough to diminish the chances of a negative gain at the muzzle? If gain is always more accurate why isn't all rifling cut with gain?
Tim May:
--- Quote from: Daryl on January 08, 2022, 01:46:13 AM ---
--- Quote from: Tim May on January 07, 2022, 09:55:25 PM ---Thanks for all replies. Just undisighted
What to with this barrel it is marked
J.J.J.J.
Large. No other stampings
Tapered 1and 1/8 to 1 in. 45 cal.
36 in long gain twist.
Thanks
Tim
--- End quote ---
The .58 Large Barrel I had, was choked for sure but did not have a gain twist.
Are you sure it's got a gain twist?
--- End quote ---
Darlyl , pretty sure looking thru breech rifling looks
slow. Looking in the muzzle end is noticeably faster twist.
Daryl:
Could be, Tim.
I would expect Bob Roller should Know for sure.
A long time barrel maker here in Northern BC, now retired, said as he pulled the buttons through the barrel, he would
attempt to advance the ROT slightly, at the muzzle. He didn't claim any better accuracy than the "big" houses in the States,
just that his bls. would give as good accuracy as Shilen's barrels.
I've shot many amazing groups with Bevin King's barrels. It shows something that Dan alluded to, in that the rate of increase
needs only be a little bit.
I do know that modern BR shooters have barrels 'gauged' & "charted", and cut ahead of an increase in the rifling twist, if possible,
from a much longer rifled blank.
I read about this back in 1996, so that technology has been around for a while. It was noted, that this was likely where "Screamer"
barrels came from.
Dennis Glazener:
Please do not continue making posts about revolvers of any type, they are against ALR rules! I have removed several posts this morning. They feed on each other and other members think its ok to do the same.
Read our rules here: https://americanlongrifles.org/forum/index.php?board=541.0
Dennis
Navigation
[0] Message Index
[#] Next page
[*] Previous page
Go to full version