I have--

[dave]

a Rem. 720 with a custom 24" stainless barrel, in .223 on it. I got all the info on it when I purchased it used. I have lost it and its been awhile so do not remember any of it, except barrel maker is or was in Ind. I am trying to figure the twist, usual method, mark rod, count turns, etc. Figuring the rifled only part of barrel (18 1/8") I get 13.4 turns, which seems very odd. Using total barrel length I get 16 turns.
Which method is correct? Thanks for any help.

[Litt'le Lee]

you mark your rod and only count 1 revolution-mark your complete one turn and then measure between--if 12" between
marks you have 1in12--the distance between marks is your end number--not the barrel length

[dave]

Aw, that makes sense. Back to the drawing board! Thanks! When I get it correct I will be back with the obvious questions about bullets & loads. It is very accurate now with Rem. ammo with the green tip bullets, off hand do not know bullet weight (ammo not at hand).

[mhb]

Are you sure that your rifle is built on a Remington 720, and not a 722? The 720 is the last of the Remington sporting rifles built on a modified 1917 Enfield action, while the 722 was one of the post-war actions which led to the current 700 series of rifles: it would be a considerable gunsmithing project to convert a 720 to .223 (altering the magazine, bolt face, extractor and ejector, etc.), while the 722 was made for the .222 and .222 Magnum rounds, and would need little or no modification other than fitting and chambering a new barrel to convert to .223. In fact, it is possible to rechamber the .222 to .223 with no other change.

mhb - Mike

[Sunray]

"...do not know bullet weight..." 62. Your issue is that the 720(AKA Model 30. Only 2,427 720's ever made.) was only made in 1941. Long before there was such a thing as .223. A custom barrel can have nearly any twist. Any markings to indicate who made the barrel?

[Dollar Bill]

Remington also makes a 50 grain load with a green tip, but 62 grain bulk is by far the most common.

Back when your rifle was made, 1:12 to 1:14 twist was the most popular because it was viewed, outside the military, as strictly a varmint round. 52 and 53 grain varmint bullets generally deliver outstanding accuracy.

As MHB noted, you probably have a 722. Relatively common and often chambered in .222 and easily rechambered to .223.