44-40 ROT Revisited

[Cliff Fendley]

I can't get any of my newer Uberti with the fast rot to shoot as well as the older ones with 36 rot. I don't know if its the quality of uberti barrels gone to the dogs or if the rot is the culprit. I just know the older ones I've been experimenting with shoot better once you get out beyond 75 yards or so.

[Lucky R. K.]

Has anyone shot an Uberti 44-40 rifle/carbine with their new 1 in 20" rate of twist at 50 yds. & beyond to see if it will stabilize a 200 gr. bullet worth a damn? I have a bad feeling about this drastic change. 

There is a mathematical formula you can use to calculate muzzle velocity, twist rate, bullet length/weight.  Google The Greenhill Formula. It works.

Lucky

[PJ Hardtack]

Best discussion I found on the Greenhill Formula was on the British Military Forum. Seems it matters if you are discussing lead bullets, the constant needing to be changed.

In addition to bullet weight, bullet length is an issue. Both short and long bullets can be accurate in a given twist, but not necessarily at all ranges.

But the bottom line remains - long heavy bullets generally require a faster twist.

I had an ERMA Gallagher carbine with a ridiculously fast twist .54 calibre barrel. It was supposedly intended for use with RB, but it shot Sharps 'ringtail' bullets rather well.

I had it relined to .50 and it shot Lyman 515141 bullets even better. IIRC, the rot was 1x26.

[Advertising]