Has anyone used the Angel Custom Thunderstorm M4 adapter for use on an M249? I have been trying to find alternative magazines for it. Not that the CA/TOP/STAR box mags are bad (inherent issues aside) but, a smaller, less intrusive magazine would make handling the gun much easier. I'm specifically looking at magwell fit, feeding issues (or lack thereof), handling, ease of reload, durability, and/or weather-resistance. Thanks!