Headspacing/Muzzle brake adjustment on FLCP-K

[Pazzoco]

My bolt head is damaged, and I'd like to replace it with an aftermarket one. I've never done head spacing, but I read an article at brownells.com on how to do it. I'm not going to recite the whole process, but basically, I'd loosen the barrel nut, and screw the barrel in or out to gain the correct spacing, using a go- and no-go gauge. Then retighten the barrel nut, and give the nut wrench a tap with a rawhide hammer for the final tightening. My concern is that my muzzle brake will no longer be at the correct position, because it will be turned slightly. I have no idea if that will affect accuracy, or if I'm just being OCD. If the muzzle brake does have to be perfectly where it started, how is it adjusted? And if anyone has any editing they'd like to do to the way I understand head spacing, as I said, I've never done it, so suggestion are appreciated. Thanks guys

[Hotolds442]

The only thing I'd add to your procedure would be to recheck the headspace after final tightening. The barrels are threaded at 20 threads per inch, so one turn is equal to .050" Changing a bolt head obtained from a reputable source should keep your headspace difference less than .001 if there's any change at all. Thats equal to 1/50th of a turn of the barrel, hardly enough to affect the timing of your muzzle brake. Being off a bit won't hurt it at all, but there's always that one guy that'll let you know it's not indexed. The brakes are screwed on to the barrel, a good gunsmith could shim it in a matter of minutes to index it correctly.

[Pazzoco]

I'm either going to get one from pacific tool and guage, or from savage, if they'll send me one free. Thank you.

[Pazzoco]

So it's just a matter of adding shim stock behind the brake?

[stangfish]

So if I understand your concerns it would be that an aftermarket bolt head would have different dimensions from the bolt face to the datum(action recoil lug). Legitimate concern. If I remember I have seen a difference of as much as .025". That would be anywhere up to 180* rotation in or out. Therefore, depending on your brake type you would need to have it timed by machine work, adding shims or adjustable locknut.

This can be done by removing material off of the face on the barrel or the face of the brake. For each .001 removed the brake will rotate 7.2*...or add shims using the same formula..

[Pazzoco]

Stangfish, what do you think the chances of a bolt head from savage being perfectly identical are?

[sharpshooter]

All of the factory bolt heads I have checked seem to be consistent within +-.001".
PTG...who knows, he makes them to his dimensions.