Seconding what Chris above me wrote, I'd recommend these P90 mags, but given it 5 stars cos I've been dealing with cheap chinese ones up til this one and this is just made that much better. As Chris says, a little spray of silicone lube always helps, but these do feel well built and solid. If you have a P90, get one...
Reviewed by Chris on 20/01/2012
These are rumoured to be tricky from time to time, Ive not had a problem with the 2 I got here. The low capacity for a high cap ( 300 ) is balanced by the fact these bad boys are silent at all times ! Ideal for sneaking up on your opponent. Also the charging wheel is inset at the top and can be fiddly, but if you have an alan key to spare it goes from fiddly to simple. The filling point for the BB's is relatively small but with a little practice you wont have any issues and i would recommend a quick spray of silicon lube into the middle every so often to keep it smooth.
Solid, smooth and unique !