King Arms WA M4 GBBR Body review

King Arms WA M4 GBBR Body review


The item was supplied directly from King Arms in Hong Kong. As per usual there communications are fantastic. Help is easily obtained from them. There was a delay in sending the item, but that was down to a big show in the middle of talks.


The item was very well packaged in a large box; I think there was as much bubble wrap in the box as the actual size of the box that held the Body. This really did ensure that the item was not going to get damaged.


I was notified on a Saturday that the item was posted, Tuesday morning it had arrived. That is what I call very fast postage. Hong Kong EMS was used. I can highly recommend this service based upon this experience.

1st Impressions:

My first impressions on this body were the box was empty, it was so light. Opening up the box, it was there. Comparing the upper receiver weight of my AGM body to the complete weight of the KA body, the AGM is heavier (and it’s only the top half against a whole receiver). The box it comes in is well padded, and has a detailed installation instruction set with it.

Also supplied was the barrel nut which looks to be Steel.

Ease of fitment:

Fitting the body to my gun was fairly difficult but only because you need to swap over all the parts. I was also upgrading a few other parts inside my rifle so it was slightly easier for me in this situation.

Trying to separate the top and lower receiver to start fitting parts into it was very difficult. Putting in the front pin assembly made the job of separation easier (this shows the tight tolerances KA have gone to with this receiver).

I ran into a problem with the rear bolt retention pin and spring. The spring was too fat for the hole it was supposed to go into. After digging around in my spares box, I found a spring that was small enough to fit into the hole. It was also stronger than the AGM spring, so the pin didn’t pop out of the receiver like it used to on the AGM receiver.

Fitting the Stock became a nightmare; the buffer tube from the AGM was a fraction to thin causing wobble in the receiver, doing the buffer tube nut up didn’t remove this wobble. I decided to take a risk and ordered a Replica Magpul UBR stock assembly, hoping a new buffer tube was included as it looked in the pictures.

The only other problem was the AGM bolt stop holder is a fraction to large, filing this down and it fitted perfectly.

Other than these few little problems, everything else fitted with no hassle. This is nothing to do with the King Arms receiver, more to do with the quality of the other brand parts you are installing into this.


The receiver is CNC milled aluminium with engraved markings which are very well engraved. There is laser etching on the one side for the TROY logo.

All the markings are officially licensed. This adds a bit more realism to them as they are accurate to the real rifles.

The tight tolerances and precision of the milling is noticeable when you assemble the rifle. Everything is tight fitting with no rattles.


If you are after a new receiver for you GBBR M4, this is a nice replacement for you to use, you could also use this to build a rifle from scratch, but I would rather go for the complete built ones that are on sale. You could get the same receiver but in a fully built rifle from King Arms.

The quality of this item is as usual with King Arms products, very high and very well made, you then have to upgrade the internals to be as high a quality.

All in all, it’s a good purchase, but I think next time I will ditch all my AGM parts and buy the complete rifle.


Construction: 9/10

Usability: 6/10

Ease of assembly: 6/10

Value for money: 6/10

Aesthetics:  8/10