Suprise, there is no standard bore size among barrel makers. This is why I have sets of pilot bushings in 0.0002" increments for most of the smaller calibers and in 0.0005" for the big bores. Example: 30 cal. barrels run from about 0.298" to about 0.301". The snugger the pilot in the bore, the more accurate the chamber or crown if one uses the piloted crowning tools. Thus the sets in 0.0002" increments for benchrest and match rifles.



Big bores are especially bad, example, in the 416 barrels, I see bore sizes from 0.408" to 0.4115". Big range, so you gotta have a good selection of pilot bushings. And you gents shooting solid bronze bullets wonder where the pressure variations come from: Difference in rifling depth and engravement of the bullet.



You should buy all the pilots mentioned. Then, as your work builds, buy more in smaller increments. I have about 200 pilot bushings in the collection.



Decide early which reamers one will use. I use Pacific Tool. Pacific Tool and JGS bushings have the same internal diameter for a series of bushings. Clymer is different. Meaning Pacific Tool and JGS bushings will not fit Clymer tools and vice versa.

My guess is the CF pilot is .213. Typically the standard pilot shipped with a removable pilot reamer is .009" under bore size.

Brownells lists a .211, .212, .213 and .22 centerfire pilots for their muzzle crowning tool. Which one is suggested for crowning stadard factory rimfire barrels? Do I need to buy all of them and use the one that fits best on a particular barrel. The .22 is the only caliber that seems to have multiple pilot sizes.
Thanks,
Weagle.