Separating M4/M16 Reciever - Swing vs Slide

[Cokeman]

My first two M4's were an Aftermath and an ICS-128. For both of them, the upper and lower reciever can be separated by rotating/swinging about the front body pin (right in front of the mag well). I just worked on my friends King Arms M4 Colt and we found that it's reciever had to be separated by sliding them apart. It was also very difficult to separate, and even more difficult to put back together (with lots of things to catch on, as well as alignment of the mock bolt carrier).


I've done more searching on the internet and it seems that most of the M4/M15 are the sliding type (King Arms, ARES, Classic Army, JG). Does anybody know which other airsoft M4/M16 have a reciever which separates by swinging apart?

Also, What is the advantage of using the sliding design?

[ThunderCactus]

Old Marui M4s, I think all GBBR M4s? and systema PTWs swing apart

Some older plastic guns had thin tabs to try to emulate the real steel method as best as possible, but those plastic tabs were pretty weak, I think everyone switched to the sliding method for AEGs.

A PTW and most GBBRs replicate a real steel receiver where the upper receiver has a sturdy crossmember for the rear body pin to hold the receivers together, obviously if there's a mechbox in the way that tab can't be there. This was solved with the sliding receiver whereas the rear buffer tube area that mates with the upper has a lip or pins to lock the receiver halves together.

The sliding method is the strongest way to keep the two halves together with a mechbox in the gun

[Cokeman]

Thanks for the explanation. If the upper/lower reciever are metal and the tab on the upper reciever is also metal, wouldn't the swing method be just as strong?

Originally Posted by ThunderCactus

Old Marui M4s, I think all GBBR M4s? and systema PTWs swing apart

Some older plastic guns had thin tabs to try to emulate the real steel method as best as possible, but those plastic tabs were pretty weak, I think everyone switched to the sliding method for AEGs.

A PTW and most GBBRs replicate a real steel receiver where the upper receiver has a sturdy crossmember for the rear body pin to hold the receivers together, obviously if there's a mechbox in the way that tab can't be there. This was solved with the sliding receiver whereas the rear buffer tube area that mates with the upper has a lip or pins to lock the receiver halves together.

The sliding method is the strongest way to keep the two halves together with a mechbox in the gun

[ThunderCactus]

no, because they are still thin tabs, now they're just inferior pot metal.
And I can't speak for every model, but the old marui plastic tabs actually required some bending and flexing action to get it into the lower.
The sliding method is honestly the best way to go about it unless you have the room for the cross member

versus plastic tabs

[MaciekA]

If you were going to choose one receiver by which to judge the sliding design, the King Arms M4 would be the worst one to judge it by. The tolerances on that receiver are completely over the top too tight (especially the back end).

[ThunderCactus]

And G&P is generally too loose lol
CA is actually pretty damn good for sturdy receivers, but their pins sometimes break, and you'll be stuck with a shiny CA receiver

[coach]

The CA's are pretty good but I also found them to have really short nubs

Madbull receivers are nice but remember to put a dab of glue on one end of the pins as they are tiny and tend to slip a lot.

[Cokeman]

Thanks a lot for the explanation everybody.

[Styrak]

The first picture ThunderCactus linked is actually a real steel upper receiver.
The airsoft version has no crosspin chunk attached at the back.

[ThunderCactus]

Actually it's a PTW upper, same thing basically

[Styrak]

Originally Posted by ThunderCactus

Actually it's a PTW upper, same thing basically

OK well, in the airsoft world, not common. PTW's are still a small minority.

[ThunderCactus]

Depends where you live lol

[Azathoth]

Originally Posted by Styrak

OK well, in the airsoft world, not common. PTW's are still a small minority.

Not true. PTW ownership in Alberta is very high. As a percentage of "ACTIVE veteran players" IE people actively playing over 4-5 years. I would guess that PTW ownership of active players is around 66-75%.

One more thing to add with the metal tabs. I don't even know if the old style metal tabbed metal receivers are still in production. In the handful that I worked with grinding off those tabs made manipulation and fitment between upper and lower FAR better.

[Styrak]

Originally Posted by Azathoth

Not true. PTW ownership in Alberta is very high. As a percentage of "ACTIVE veteran players" IE people actively playing over 4-5 years. I would guess that PTW ownership of active players is around 66-75%.

But in Canada, it drops down to a small minority. Anywho, getting offtopic...