Looking for V2 gearbox suggestions

[grumio]

I'm looking at getting an E&C M4A1 receiver set as it's the only thing I can find with full Colt trades. I want to get a new gearbox shell for this but not sure what to look for in terms of something that would work well and make tech work easier over a non QD shell. I've seen the retro arms split gearbox but I'm not sure if this is worth upgrading to over a standard QD. Would be great to know what makes to look out for/avoid as well. Cheers.

[Speedbird_666]

I would get an E&C shell. It's QD and from the same manufacturer, so should be a drop-in fit for the receiver.

 

As an owner of many ICS M4s with split gearboxes - it's a nice feature to have - IF the gun was designed from the outset for it. However, it's certainly not a strong enough feature to justify spending a big chunk of cash on a mere gearbox casing.

[Lozart]

Second the E&C gearbox. It's what the original Specnas came with and it's been the basis of at least three builds for me so far.