I was looking at several entry options for complete rifles in the market for a few friends looking to pop their EBR cherry. I came across several Del-Ton 316 rifles and was impressed by the reviews and the prices. But I did have a question about the different models. I think I get the differences but correct me if this is wrong:

316 line:
The Sport line uses a carbine length gas tube and a lightweight1x9  barrel
The Echo line uses a carbine length gas tube with a M4 profile 1x9 barrel
The Sierra line uses a mid-length gas tube with a heavy 1x9 barrel
The Extreme Duty is the Echo with a hammer forged M4 1x7 barrel with a Troy rear sight

Additional info:
An H in the model name designates a heavy profile barrel
A G in the model name designates a government profile barrel
A PF in the model name designates a non-threaded crowned barrel and a 10rd mag
The 216 and 220 lines use A2 uppers
The Alpha 320 line uses a rifle length gas tube with a government profile 1x9 barrel
And the upgraded models are self explanatory, ie. MOE, TRX, Evolution