Hi guys, I have a very basic understanding of airsoft teching, so bear with me if I'm doing something stupid. I have recently bought a second hand Tokyo Marui M4 AEG, I'm not 100% certain but I am pretty sure it's a tokyo marui m4a1 carbine aeg. I am trying to remove the inner barrel but can't seem to get the upper and lower receivers to separate, I have removed both body pins and am pulling the charging handle as you usually would, and there is a little bit of movement, but they won't separate as they should. The gun has had a replacement stock and front handguard as seen in the picture, so not sure if that makes a difference. Any help would be massively appreciated, thanks!