you dont get long and short M16s, the carbine of an M16a1 (vietnam) is a CAR15, or the carbine of the M16a2 onwards is the M4a1 and other varients. 5.56mm armalite DMR rifles include the stoner rifle (knights armourments?) series and the SPR varients. The SR25 is a 7.62mm armalite DMR that works very well, i belive (correct me if im wrong) its a popular favourite among american snipers. Anyone know if delta are still using M21s for marksman rifles?
Then ofcourse you get into barret or M24 territory. American and english police both use the sig550 DMR, which (imo) is one of the nicest looking guns on the planet, other than anything made by H&K.
Well tbh Moset American MEU are using a M16A4 (m16A3 was a M16A2 with fully auto, while the M16A4 is basically a M16A2, but has a better scope, which led to the thought american soldiers where executing prisoner, when actually they knew how to use those new scopes. Unfortunatly most Army Reserves get stuck with the M16A2)
Then again your in the UK so I wouldn't expect you to know alot about american arms.
Also the sniper prefrence. My cousin was a sniper servering in Bosnia, Panama, and I believe also Somolia. He told me himself he prefered the M24, but then again he shot that, a M40 and a Barret only, and he thought the Barret was unnessesary firepower.
Also the M16A1 isn't really a CAR15 if you want to be picky, since the CAR15 had a retratable stock.
Glad to see another gun enthusiest on the forums