Thread: .17 Mach IV Barrel

Originally Posted by Wingman

Sorry I have written that info around the wrong way... it is the .17 Mach IV that is longer than the .17 fireball not the other way around. The bolt on a Remington fireball will not close in a mach IV cartridge.

While you might "get away with" firing .17 fireball in your .17 Mach IV it is not good practice. The cartridge body is 6 thou shorter than you chamber so add 2 thou for the std head space clearance and you have a total of 8 thou of head space.. your brass will migrate forward or backward to match the mach IV chamber but at the cost of side wall thinning just forward of the base cup with the risk of case head separation especially if you reload your brass.
Im keen to see pics of your .17 fox if you have any?

I'll take some pics for you. The 17fb ammo is a firm close in my mach iv. I had a heap of cases when I got the rifle (over 200)but the necks have been splitting or were already split they were formed from 221Fb.