We GBBR M4 Internal and External Upgrades

[Keccott1610]

Hi everyone 

I've had we gbb m4 for a year now although I havent had much time to use it during covid im looking in to upgrades internally and also is there a 416 delta style rail that would fit and if so where could I get one.

Many thanks.

[Cyberlawyer]

There are several clones of the Daniel Defence Mk 18 rail that will fit.

 

416 rails also need a different upper receiver otherwise the top rail won’t line up as the real steal version of the 416 is a piston gun so there is space at the top of the rail & receiver for the short stroke gas piston system.

[Nick G]

Internally, it's worth fitting a Maple Leaf hop rubber and think about getting a Real steel charging handle . You may need an NPAS if you dont already have one, all my GBBR's have run hot out of the box. 

 

My GBBR L119 A1 is based on a WE and has a number of real steel fittings. Buffer tube,  pistol grip, stock, charging handle and carry handle. I've got a RS bolt catch to try too at some point. As Cyberlawyer said the 416 front would require the correct upper too. But plenty of railed fronts available if that's what you are looking for.

 

Nick

[PopRocket123]

I'm looking at getting one of these. Are the co2 mags worth the extra hassle to run them in winter?

[Nick G]

Everything I've seen suggests the CO2 mags are very prone to leaking. I tend to run red gas in mine all year. Might try black at some point.

 

Nick

[EDcase]

Co2 (around 900psi) is much higher pressure than even Red gas.

So the exit valve of a Co2 mag has to be much more robust and should control the output to rough working pressure of the rifle but will often be at the high end.  So rifle parts will take more of a beating.

 

Even though their output is usually consistent until they are empty, there are a couple of big arguments against Co2.

1) If you have a leak you will use a whole bulb ever time to test if its fixed and if not then its wasted.

2) You cannot top up at the start of a game.  So you either have to waste what's left to put in a new bulb or risk running out mid-game. (You can of course refill mid-game but its not so convenient)

Edited March 20, 2021 by EDcase

[PopRocket123]

Thanks guys. I've talked to someone who really knows his stuff with these guns and he's recommended running straight propane and keeping the mags well lubed. Having seen his videos of a 888 running full steel internals and still locking back after a full auto mag dump I think I'm going that route lol. 

[CrackCommandoUnit1972]

I have seen this online. Anyone used one of these?