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I have a sako action with a berger barell on it it is now chambered for 222, this is a older rifle and i still am not sure of the twist, the old method of cleaning rod and measuring twist and length just does not seem to wrk
am considering rechamber to 223, comments?? all it will take is a reamer and skilled smith, right??
Odds are it is a 14" twist. I rechambered several M788 .222s to .223 many years ago. All that was required was finish reaming to proper headspace. There was a slight step left in fired .223 cases where the body of the .222 met the shoulder. This did not bother anything and presented no problems at all when either FL or NSing fired .223 cases. The barrel could be bulled and set back 1/2 to 1 thread to alleviate this.
Accuracy was excellent with reloads when using commercial 50-55 gr bullets. With M193 (military load with 55 gr FMJ) accuracy was ok until temps got below freezing then stability became an issue. I quit doing the conversions because the M788 came out in .223 with the same 14" twist.
Actually I would recommend leaving the rifle as a .222. Modern powders and bullets of 50-55 gr nip right at the .223's heels. Cases are also easily formed from .223 brass if that is an issue. A couple hundred .222 cases that are mostly NS'd with out last the accuracy life of the barrel.
Larry Gibson
"...cleaning rod and measuring twist..." You must be marking the rod incorrectly. Patch on jag and gently, push it into the chamber until it hits the bore. Mark the top of the rod at the chamber end and on top near the handle. Push the patch through the barrel until the handle mark make one complete turn/revolution and mark the chamber end again. The distance between the chamber end marks is the distance of one turn of the rifling twist.