My way is
1A= A-bbreviated barrel (22" vs 26" with sights)
1B= B-are barrel (no sights)
1H= H-eavy barrel (with sights)
1S= S-ights on barrel
1V= V-ery heavy barrel (2 scope blocks no sights)
RSI= I-nternational (stock goes to muzzle)
Add a K for stainless