What blank are these? Any way of telling manufacture? I was told shilen?

John primarily uses Wilson blanks and also some Shilen.

If it's Shilen, it will likely say that it's Shilen in the literature................if it doesn't, it's likely Wilson. Can't remember for sure, but I think all WOA's Shilen barrels are 5R.

You can always call WOA & ask; they are very user friendly.

MM

I have one, an 18" SPR, and it's a good shooter! Loves 69 grain SMKs. I haven't gotten around to the 77s, yet.

Rifle or mid gas? Rifle gas is on sale for $239

I prefer rifle gas on an 18" barrel. Runs smooth and no need for an adjustable gas block with a suppressor.

Sorry bout that, mine's a mid-length.

War Eagle has an excellent point with his post.

I agree with this and add that I did quite a bit of chronographing last summer with several different 18" barrels. You gain 100fps+ with rifle gas over mid length