How to measure the FX Impact X 700mm barrel.

I recently bought an FX Impact .30 cal with the 700mm X barrel system. The barrel seems to be short for a 700mm/ 27.5 in barrel. 

I wonder if they sent me the standard size barrel instead by mistake. Is the barrel measured from the inside barrel liner or from the end of the barrel to the end of the moderator with the shroud on? If your have an FX Impact with a 700mm barrel can you please share some insight on the proper barrel length measurements. Thanks 
 
Yeah i get it, sure its not closer to 27 and 5/8ths? (exactly what you payed for)

Heres how a 600mm measures, its hooked on the other end of liner.

700mm should be 4 inches longer.

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