King Arms M4a1 fitment issues

[logoris]

Originally Posted by venture

There are 2 things that stop the KA receiver from going that last 1.5mm.

1) What Stealth Alluded to, you need to "pinch" the upper receiver near the back so that the tabs will slide into the lower. Just use your fingers for this, not vise grips. These receivers are brittle.

2) The gearbox has to line up properly with the hopup so that the hopup kind of goes into the front of the gearbox a little bit.

i did try squeezing by hand it wasnt even budging the hop is 100% lined up.


i just chronod my gun, what spring are you guys using to make it cqb legal im hitting 390fps+ consistantly

[HKGhost]

I've seen this so many times with the King Arms m4. The only way to get the receivers to come together is to loosen the pistol grip and buffer tube. Get those very loose but not coming apart. Coming apart completely is not an issue. Then slide the two half together and maybe a bit of banging with a mallet with get it on. Remove the buffer tube completely and bang on the stem for the buffer tube.

[Stealth]

As TC said, do NOT use any tools. You do not need any. Do not bang anything FFS.
Judging by the first pics you posted, the charging handle does need to be pulled back slightly to remove the vertical gap between the upper and lower receivers first. THEN pinch the rear of the upper receiver and slide in. Oh and make sure your front bodypin isn't blocking anything as well as the ejection port cover.

Screw it, just sell it to me.

I'll start the bidding at $50.

[HKGhost]

Trust me, some of these KA receivers need some persuasion from a soft face mallet. The QC from the factory on these is almost nonexistence.

Originally Posted by Stealth

Screw it, just sell it to me.

I'll start the bidding at $50.

But seriously though, as TC said, do NOT use any tools. You do not need any. Do not bang anything FFS.

[ccyg8774]

Is your fake bolt in the right place? In some KA M4A1 they tend to be pulled out of its "rail" as you lift the charging handle to pass the little bump on the gearbox, then the bolt piece will prevent the upper receiver to fit in properly, just like the way in your pic. There is no easy solution for that, you will have to pull the charging handle as little as possible, and keep a finger in the fake bolt as much as you can to hold it in place.