G&G blowback M4 - quick tech review

[m102404]

I had a G&G M4 blowback come in for repairs and a checkup. This one was originally from Mach1 Airsoft....I don't know first hand the difference between the one they sell (higher end of the clear receivers) and the others (i.e. lower quality ones).

Pneumatic system:
- quite an ingenious design. There is a simple hole in the cylinder at the front near the cylinder head that allows air to get pushed up into another small cylinder riding piggy back on top of the mechbox. The piggy back cylinder is about the size of a pencil (people still use pencils...right?).
- The piggy back cylinder has it's own piston that is forced back under pressure, until the piggy back piston head clears a vent, where the air escapes and the system depressurizes (the bb has probably left the barrel by then as well).
- the holes between the piggy back cylinder and the main cylinder are sealed by a rubber grommet/gasket. It's quite soft...so take care not to nick/tear it.
- at the end of the piggy back piston shaft...there's a c-clip that holds the fake bolt. Under pressure, the bolt is pushed back...with lack of pressure a spring snaps it back forward. It's not so hard that if you stick your finger in it that you'll think you'll loose your finger tip (tested that...).
- it travels back about half the length of the complete ejection port.
- unlike other "fake" dust covers...this one straddles the mechbox and rides in a slot on both the right and left sides of the mechbox (the slots are actually on the piggy back unit).

Internals:
- pretty typical stuff. very "sportline"-ish. Solid and tidy. Thumbs up...nothing a little TLC can't make better.
- big bronze bushings (9mm?)
- shimming was extremely poor, greasing/compression was decent
- spring guide is metal...but the plain, no-bearing type
- piston head is poly...with the "tornado/vortex" type ports
- piston is poly...2nd tooth already removed.
- AOE was a little early
- wiring/solder was good
- the spring release forward assist was a great touch...it works well

Externals:
- sportline-like...nothing great, nothing overly poor.
- the upper and lower come apart like a "CA"
- putting back in the front pin is absolutely horrible. A LOT of "gentle" force was needed to get the front holes even remotely lined up. The pin fit is extremely tight throught the lower. I can see a lot of broken lowers from guys monkeying around with their AEGs.

[Crunchmeister]

Of all the blowback designs seen to date, this one seems to be the best thought-out to me, using air from the main cylinder to power the blowback action, rather than a mechanical attachment to the gun's internal action. This ensures that the fake bolt carries always returns to battery with every shot, rather than the potential of stopping partways open when firing in auto. I still think the blowback mechanism is useless on an AEG, but this one seems like the best concept to date short of an actual GBB gun.

[wildcard]

Originally Posted by Crunchmeister

when firing in auto. I still think the blowback mechanism is useless on an AEG, but this one seems like the best concept to date short of an actual GBB gun.

It seem that all the AEG coming out from reputable companies now comes with BB action just look at King Arms, as for reliability issue I just don't know what to think, Logic dictate that the more moveable parts, the more problem it will have but company like King Arms, TM, CA, G&G, G&P and even VFC are all getting into the BB action. Only time will tell

[Crunchmeister]

I can certainly agree with that. This fake blowback action really does nothing for me. I'm all for simplicity as well.

It has no purpose other than to "look good". And quite honestly, I think it looks like ass for the most part. The other blowback designs are relying on the internal action of the cylinder to position the fake bolt carrier. Firing in semi, the mechbox does a full cycle, so the bolt always returns to battery. But if firing in auto and you let go of the trigger in mid-cycle, then the bolt stays cocked back. And I fail to grasp how exposing the side of the mechbox / cylinder - something that REALLY shows it's not a real gun - helps increase the realism factor.

But if they're gonna be making these things, then I think at least G&G seem to be the ones to have the right idea with this using a pneumatic blowback system instead of a mechanical one. For every BB fired, the fake bolt carrier always returns to battery when you release the trigger. At least on the cosmetic aspect, it doesn't look bad. It's still ugly to me, but the design of G&Gs system is its one redeeming factor that at least makes it better than the others.

But I still think it's a useless feature that can only cause complications and possibly parts compatibility issues. As you said, more moving parts means more potential for problems. If the part has no practical use, then I don't want it on my gun.

[13Fido13]

I have to agree with all that was said here but i do have some different ideas on the subject as well.

I've just picked up an mp5 blowback, I'll be testing it this weekend and checking out what it's made of. I'll update after that.

As of right now with a few shots fired it has a good sound to it, and sounds like it has a wicked hit. I can't wait to chrony it.

Updates to come.

[Colin_S]

Hey Tyson quick question for you, did you find a piece of plastic in the groves of the buffer screw? If you did how did you remove it? I picked one up just as a loaner and for the life of me I can't get that piece of plastic out and which makes taking out the buffer screw impossible.



Hope that comes out ok.

[panzergrenadier]

I didn't have a peice of plastic in the groves of the buffer screw... that's weird

[m102404]

Not on the ones I had...but try a flat screw driver...hopefully it'll catch and jam so at least you can get it out.

Tys

[PaddMadd]

Overall, the look of the blowback is a nice detail, hovever I prefer the dust trap closed(pet peeve), so having the extra components that wouldn't be seen would just be extra weight, even if it is a small ammount. With that said as far as quality goes, could someone expect the same quality and performance from the blowback version as the standard G&G M4?

[KenC]

Hi Guys,

I'd like to clearify that the Blow Back GR16 from 007 airsoft are with C8 maple leaf receiver (not combat machine), and proper 9.6V 1400mA NiMH Nunchuck batteries as recommended from the manufacturer (not 8.4V 600mA NiCd mini ). Our prices are different as well, mine being lower.


However both have the same internals (Plastica series internal)

Ken
007Airsoft

[Skladfin]

I was wondering..

can't you sand down front pin so it fits easier?

[13Fido13]

Originally Posted by KenC

and proper 9.6V 1400mA NiMH Nunchuck batteries as recommended from the manufacturer (not 8.4V 600mA NiCd mini ).

Are you saying that using anything less than a 9.6v battery will not function properly. I gamed my MP5 blowback and noticed that the battery died really quickly both with an 8.4v battery and a 9.6v battery. Any explanation as to why this is happening? Heavier springs inside? etc?

[Gravewolf]

I never liked blowback on a rifle cause it looks so unrealistic plus it another extra part of the gun to take care of. I saw my friends romanian AK47 and it usually blows back halfway. I prefer that manufacturers put their money on more reliability and better performance than waste precious r&d money on gimicks.

[Malice Army]

Has anyone done a side by side comparison between a blowback and same in a non blowback? Same velocity?rate of fire?noise level? accuracy? Does the blowback "kick" ?
I'm a sucker for "gadgets" , but not at expense of performance.

[device]

Hi all!

Guys! Can anyone of you measure those g&g pneumatic blowback parts? I'd be very pleased if you could tell me some mm-s what is it made of, how big high deep are those parts,what are they made of etc...


God, I cant wait till you write an answer !

Thanks anyway,

Tamas Antal
Hungary