TM scar H extended length - internal barrel length

[Sneaky]

Hi all. I’m looking to buy an TM scar H soon. I want to know what would be the inner barrel length with the additional barrel added. I have been told 363mm (M4)  but on the link below they are saying 407mm. 

 

https://overhoppers.wordpress.com/2014/07/02/tokyo-marui-scar-h-dat-hop-up/

 

Anyone who owns a TM scar that has done this please could you tell me the extended inner barrel length, just to clear this up once and for all. Also this will dictate if I need to replace the cylinder. I will do the work myself as I have many years airsofting experience.

 

Thanks all.