GHK M4 V2 Bolt Carrier and Magnetic Bolt Lock Kit for GHK M4 Gas Blowback Rifles

"Solid construction in terms of the bolt carrier itself, and it has a steel insert so filing the part where the bolt catch mechanism engages is no longer necessary like on the V1. That in combination with the magnet/adjusted bolt catch design engages the bolt lock almost every time, even with a Magpul BAD lever installed, whereas the V1 bolt only worked maybe half the time and not at all with the BAD lever. Massive improvement. Even a nice metallic sound when firing when compared to the V1.

Getting the roll pin holding the bolt catch in place out to do the install is a bit of a PITA though if you don't have roll pin punches. I managed to use some small flathead screwdrives in their place.

The magnet is by far the worst part of the design, it's made of some weak material and mine actually snapped in half during the install. I would instead recommend getting Deryun mini magnets or something similar size, as those are made of steel and should work just as well. The plastic part seems not to be necessary for functionality and it's extremely easy to lose but your mileage may vary.

Nozzle install was pretty straightforward, though I did need to transfer and file down the inside part of the retaining pin (the removeable piece on the side of your bolt carrier) in order for the nozzle to move freely. Getting the e-clip on and off was also quite annoying but nothing that takes more than a few minutes.

Overall, this is probably a required upgrade if you plan to field your rifle often, just a shame it didn't come this way to start if you bought a V1.