I have a Sako L579 in 308, Serial 242xx. Thinking about re-barreling. Are the threads on this barrel metric? Thanks, Jerry

Jerry

My Finnbear (L-61) and Forester (L-579) are both V 16 TPI.

Bill

Technically, it is a metric pitch. I am away from my shop right now and cannot measure the actuual thread.

However, if I remember corectly about the 579, the metric pitch is so close to an imperial TPI that they can be considered interchangable. I measured the pitch on a take off barrel I had, but the exact ones have slipped my mind. The L461 is the same way-it is technically metric, but there is an imperial tpiu that is for all practical purposes interchzngeable.

There was a discussion in a thread along these liens a couple of months ago. While technically cetrain pitches are metric or imperial, they are so close to imperial or metric pitches that you are really cutting the same thread eaither way. THis is assuming thread lengths of an inch or less as used in gun applications. When it comes down to nut cutting time, most machines, most lathe drivers, and most thread cutting tooling is not accurate enough to even tell a difference any way.

As another way to check it, you can pull the barrel off the 579 and look at the threads with a thread pitch gage and see how it looks. Just using Starrett leaf type gages, plus using my most powerful Opti-Visor, I cannot see any difference at all between the imperial and metric gages held the L461 barrel threads. With thread wires you might could see a slight difference, but again, the machine used to fit the aftermarket barrel will likely not be able to cut threads accurately enough to see that slight difference.

OK, full disclosure here. Even though I know the threads would be equally good, I cut the "proper" metric thread. I have a lathe where all I have to do is throw levers to cut eithewr imperial or metric threads, so it is no problem to do so. If I had to change gears and go through such gyrations i would just say screw it and cut imnperial threads

BTW-I have read that technically a LR Mauser uses a metric thread, but it is so close to 12 tpi it does not matter. does anyone know if this is true? If so, any idea what the "proper" thread pitch is? I am still going to use 12tpi, but am just curious about it

Thanks, WJW & Marc, Starting a project on a lathe that doesn't cut metric. Thought I would ask b/4 pulling barrel. Lots of good info, thanks again, jerry

I have rebarreled 20-30 Sako rifles and cut 16 TPI on all of them, not a problem so far!

That is true about the Mauser thread pitch.