G&G TopTech receiver swap?

[rubi-tong]

Hi all I've got a metal bodied TopTech M4 with the pneumatic blowback!
I want to swap the lower receiver for a Magpul MOE receiver, I'm aware the upper cannot be swapped due to the blowback (which I'd like to keep) but not sure if the lower can be swapped?
It's a Version2 gearbox and apart from the pneumatic blowback on top, is it the same as other V2's, if so could the lower receivers be swapped whilst keeping the blowback action?

Thanks in advance, Mark

[jonny lovegrove]

Re: G&G TopTech receiver swap?

In theory yes, it should work fine. Might be worth getting a cheap reciever just to see if they mix. And the upper can be changed with a little filing.

[rubi-tong]

Re: G&G TopTech receiver swap?

Cheers Jonny, so you think I could put a VTOR muir upper in or similar with some filing?
Would the filing be where the charging handle and blowback system are located?
Got me excited now!
If they would both go on then bugger the Magpul receiver, Noveske upper and lower for me.
Mark

[jonny lovegrove]

Re: G&G TopTech receiver swap?

Possibly, i havent tried it myself, but if you look inside the upper, youll notice that its just hollowed out more, the blowback just sits on the top of the gearbox. Might be worth asking someone who has tried, or just removing the blowback.

[Identiti]

Re: G&G TopTech receiver swap?

If i remember rightly dont they have a spring release on the gearbox too?

I know my cheaper version G&G EBB gearbox did which i fitted to a G&P lower and from what i can remember i didnt need to modify the lower

How ever the upper reciever will need more than a bit of filing to get the blowback to work, would be better off being laithed out by maybe 2mm as your need to get it perfectly round inside for the blowback to run smoothly.

[rubi-tong]

Re: G&G TopTech receiver swap?

Yes it has a forward assist to ease the spring and a bolt release too!
So the lower would just go straight it? Would have to see if it mates up nice with the upper, not sure about getting a brand new upper laithed though, lot of money down the pan if it f*#ks up!