I've owned an ICS Sig 551 for a little over a year now. Left it bone stock and I have to say I've been pretty happy with it overall. I've put tens upon tens of thousands of rounds through it and she still shoots great.
The externals of the gun pretty are nice but I wouldn't say they're top notch. 7/10
- The "plastic" parts are quite robust
- Aluminum receiver has laser engraved (?) realistic trades.
- Rotating rear drum sight gives 3 different view options and clicks solidly into place adjustable for windage and elevation. Front sight is adjustable for windage and has a second (larger) flip-up blade sight.
- The removable charging handle and functioning bolt catch in a nice realistic touch. But don't let the charging handle slam forward too many times or the piece that holds the charging handle in place will break making your charging handle easy to fall out. With the retaining piece intact the handle would be difficult to lose.
- The selector switch is very stiff at first but will become better with time.
- The trigger guard is too loose and will swing around on you when you don't want it to. I glued mine in place and it hasn't bothered me since.
- Quick & easy break down/disassembly and battery installation.
The stock internals are pretty impressive for ICS. I've put 50,000 rds + through it with zero issues. 8/10
- Factory shimming was pretty good, lubrication was also good.
- Gears and anti reversal latch seem to be made out of nicely machined good quality steel.
- The nozzle is proprietary but seems to seal well.
- Compression is good but not 100%
- Cylinder is good and smooth but cylinder head has a bit of a lose fit.
- Piston and piston head are respectable. Piston has a metal first tooth and the piston head is plastic non-ported with no bearings.
- Comes with the ICS turbo 3000 motor. This is motor performs very well, only one little issue is that it's a bit loud and high pitched.
- Spring guide is mediocre and has no bearings
- The plastic hop-up functions very well, but could probably use a better rubber.
- inner barrel is 363mm aluminum, bore?
Overall rating 7.5/10, A great gun for the price.
A 9.6 stick battery will fit nicely in the hand guard and provide a decent ROF. I've been using Mag brand 100 rd midcaps, they feed very well with a small amount of filing. *
Mod*
Recommended upgrades for best performance are as follows:
- Hop rubber
- Address compression issue
- TBB
- Ported piston head with bearing.
- Bearing spring guide
**edit: At that price ($270) this gun is a steal.