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Matrix CNC Machined Hybrid Hopup Chamber for WA / G&P WOC Airsoft M4 GBB Rifle

1 Customer Review

by Eric C. on 06/28/2017
"This was an excellent upgrade over the stock hop adjust system in my King Arms WA-system M4. The degree of hop is adjusted via a 2mm allen wrench inserted just below the chamber with the receivers hinged apart. With a free-float RIS attached, the stock King Arms hop adjust was inaccessible.

So far, however, it has eaten through a Prometheus purple bucking (over the course of two games) and an Angel Custom V-teeth orange bucking (over the course of two shots). And it may or may not have contributed to the destruction of the stock plastic loading nozzle. But I have high hopes for the Madbull 60 degree Shark red bucking [http://www.evike.com/products/28917/]. It required slight trimming on the forward end and a little bit of massaging to get it to fit, but it seems to fit snugly without protruding too far into the path of the new aluminum loading nozzle. The chamber can't take all the blame for being hungry. It's really a problem with how all of the pieces fit together - barrel, bucking, hop chamber, and feeding nozzle. So each unique build will have its own quirks. Best to have spare buckings on hand just in case.

Because I contradict the description, which says that Madbull buckings may not fit, here are the other mechanical parts of my build: King Arms receiver, barrel, and outer barrel, RA-Tech steel bolt carrier, and RA-Tech aluminum loading nozzle, bolt, locking plate, and NPAS. Again, it did require some trimming and massaging, but there are no signs yet of shredding which makes it a better candidate already than the other two I've tried.

The solid pin that holds the arm in place fits very tightly. You might want to bring the chamber to the hardware store to find one that fits -just- snug if you want to be able to remove the arm. Coaxing the spacer into place is a delicate and frustrating task if you can't remove the arm. Also, the tiny spring that sits between the hex nut and the forward wedge likes to fall out if you're not mindful when dis/assembling the barrel. I ended up replacing mine with a spare rubber hop spacer.
In short:

Pros:
Easier to adjust hop
Compatible with AEG barrels and spacers
Durable

Cons:
Small, easy-to-lose parts
Finicky about which buckings it likes
Difficult to get spacers in place