Twist rate 243 model 70 Winchester?

Answer 1

The standard factory twist rate for the .243 Winchester cartridge is 1 in 10"; for example, a used in Win. Mdl 70's, Rem's Mdl 700, and Ruger's 77. Custom barrel makers make other twists available, as slow as 1 in 12" and as fast as 1 in 8". The 1 in 9", has become useful in shooting heavier 100 gr. plus bullets, such as the 115gr DTAC for very long distance accuracy. To measure the twist of a barrel, fit a tight patch on a jag or on a bore brush, insert into rifling a bit from the chamber end (preferably), and place around the rod a piece of masking tape about 15" back from the rear of the action and mark a '+' on the very top of tape, now also magic mark your rod right at the point where it enters rear of action. If you must use the muzzle end of barrel to do this test, then put this mark where it just enters your barrel. Now slowly push rod into rifling allowing it to rotate as it follows the twist until your '+' mark has rotated one exact revolution. Now mark the rod again exactly at same point it enters rear of action (or barrel). Withdraw the rod so you can measure the distance in inches between the two magic marks on the rod...that will be your the twist rate, i.e. one turn in so many inches. Repeat to be sure. You may have to adjust your tape spot further back or use a longer rod when measuring very slow twists as found in muzzleloaders.