Looking for barrel profile info

[fedupflyer]

Looking for some info on the following barrel profiles.
Would like a reference to drawing specs if you have them.

20' SAM-R how it this different from the 18' SPR?

15.1 Mid NSW Recce vs 16' Mk12 Mod H.


I have looked high and low but I still am coming up short for the info I am looking for.

Thanks in advance.

[JediGuy]

I would recommend posting this in the General forum.