This is by far the best performance for your money M4 variant on the market. Iíve owned it for approx 2 months and have put 10,000+ rounds through it with out a drop in performance. Itís superbly accurate with a 6.01mm tightbore. It has an effective range of 110-130ft max. That figure is using Golden Ball .25ís. It could potentially have a longer range if .2ís were used but I have yet to test them. Also it has a ported cylinder so the volume of air that can be compressed is less than with a full cylinder, thus hindering its effective range and velocity. However the port does allow for the piston to bleed off air resistance as it cycles forward, thus increasing the ROF slightly. The ASGI chrono sheet claimed 350fps. I can reasonably assume that with the 6.01mm tight bore it puts it up around 370fps using .2ís.
There were 2 characteristics that I found to be more of a nuisance than an actual flaw. The first being the dust cover/ejection port has to be held open when adjusting hop-up. I assume that this was intentional being that the hop-up unitís gears are very stiff and hold itís position very well so one wouldnít need to adjust the hop-up as frequent. The second characteristic is that the triangle sight on the gun was loose. Itís an easy fix just time consuming lining up the sight then tightening it down. This occurred with both of my GR-16ís.
The magazine wobble was intended so that the GR-16's could accommodate the wide array of M4/M16 magazines. It's easily remedied by placing a couple of strips of electrical tapes on the sides and front of the magwell.
Great Value ($260 value as of June 2010)
Great External Build (6061 Aluminum making a very sturdy platform) Older models had lighter Magnesium bodies but these were prone to crack.
Great Paintjob (Anodized and Powder coated for a very scratch resistant finish)
Great Accuracy (with 6.01mm tightbore)
Good Range ( 110-130ft with .25ís, 6.01mm tight bore, stock gearbox internals, 363mm barrel length, and ported piston).
Good ROF (approx 950-1000 rounds per minute using an Intellect 9.6V Nunchuck)
Great Hop-up Unit and Bucking (Works Perfectly and stays ďzeroedĒ.
Great Reliability (So far. Iíll update it when/if I encounter problems).
Dust Cover/Ejection Port (Makes changing hop-up a slower process)
Front Triangle Sight ( Was loose when I received it on both of my GR-16ís)
Rating: [5 of 5 Stars!]