View Full Version : Sig 556xi

December 26, 2012, 06:01 PM
Went looking for a $8.00 scope mount today and ended up with a new Sig 556 xi rifle. Anyone have any good or bad experience with this or the other 556 line. I liked the pop up sights on this model over the others. Figured it was not going to get any cheaper than than the $1100 so bought it while I still can.

December 26, 2012, 08:41 PM
They're basically a bastardized SIG 550/551; they had a lot of quality control and cycling issues when they were first released, but SIG seems to have the problems worked out now.

December 26, 2012, 10:59 PM
I have read some early models had problems. Mine has had ZERO failures of any kind in the first 500 rounds.

December 27, 2012, 12:41 AM
...but my 556 Classic has been a good rifle for the first 1000 rounds or so. I have discovered that the bolt and carrier and receiver do not accumulate fouling to any extent, but it is a good idea to pop the regulator/oprod/gas tube and keep them clean.

Hope you enjoy yours.

December 28, 2012, 01:12 AM
I have a 556 Classic Swat. It goes bang every time. Many say the 556 is a bastardization of the 55X line, and my initial thought was that also. However I think it's pretty handy that it takes AR mags, so I think of it now more as an evolution. My main gripe with mine was the flimsy collapsible folding stock. It looks good and is a good idea, but has way too much play in it and rattled. I tried a few ways to bubba fix it, but ended up removing it, installing a new aluminum mounting block and installing a Magpul CTR stock (or any AR stock will now work). The only other gripe is that it is very front heavy. My remedy was to get a forward pistol grip mounted close to the mag well to improve it's handiness and it makes my elbow tuck in nice into my side for a steady hold. The pistol grip also helps with the chunkiness of the quad rail forend that makes it difficult for my hands to hold onto comfortably. Overall a great rifle though. It's a good AR substitute for those with a chip against the AR since everyone else has one. The only other improvements I have in mind is to replace the rear sling swivel hole to mount a real sling loop and a new rear pistol grip. The factory feels pretty good but is a little too big for my hand. I found a grip that is smaller in the web area of the hand, which will also make mag changes easier (the mag release is about 1/2" too far forward to release without changing hold on the grip.

December 31, 2012, 09:48 AM
Guys. I ordered up a spring kit for the 556 from a Matthias in Germany who posts on the Sig forum. Took quite awhile yesterday but got it installed according to instructions. The trigger is a bit lighter than before, but that is not what has me agog! There is now an overtravel stop, and a really quick reset.

I haven't shot the beast yet, but so far just futzing about in the living room, the reset is very nice, and I think perhaps this might make the rifle more manageable for 3 gun type stuff.

Will keep you posted.