Yesterday I happened upon a Sig 556XI Russian Pistol and despite poor reviews of the 1st Gen R models, I decided to buy this on a whim...recognizing the potential this rifle has to be an outstanding SBR. This is my 3rd Sig 556. Years ago, I bought two of the early models and had issues with canted rails and I swore off Sig as a reputable rifle maker. The fit and finish are the best of any Sig rifle I've owned. The upper and lower fit tightly, the hand guards are tight, the action cycles smoothly and the trigger is very nice and even better now that I've adjusted the plunger behind the trigger. The included sights are perfectly functional and clearly the best I've seen on any Sig rifle.

After a quick wipe down of the bore, but leaving the grease on the bolt assembly, I packed my new "pistol" up along with five different mags. The Tapco that came with the gun, a Magpul, a Bulgarian waffle Circle 10, a Bulgarian or maybe Polish smooth mag and an Egyptian steel mag. I also packed up 100 rounds of Wolf poly and headed to the range.

Here are the results:

Magpul magazine: 20 rounds, 3 FTF. In three instances, the rifle failed to feed with the cartridge partially feeding at a 45 degree angle and the bolt locking up against it. One of these was undoubtedly caused by my attempt to get a sight picture with this pistol and it was clear that I did not provide enough resistance against the recoil. This may have been the cause of the other two as I was shooting relaxed from the hip. Remember this is a pistol.

Polish magazine: 20 rounds, 1 FTF. Same type of thing as before. Again, may have been caused by a lack of resistance.

Bulgarian Waffle Mag (circle 10): 20 rounds no failures.

Tapco magazine: 20 rounds, no failures.

Steel Egyptian: 10 rounds, no failures.

Magpul mag: 10 rounds, no failures.

Polish mag: 10 rounds, no failures

In the end, I had 4 FTF (one most certainly caused by me) in the first 25 rounds, then no failures after that...particularly when I provided a little more resistance in my grip. Even the Magpul mag which gave me the most trouble was fine after I held on a bit tighter. Ejection was consistent, throwing spent cartridges about 4-5 feet to my 2 o'clock position. I did slow fire and rapid fire with no issues. Ultimately, I think this will make a fine little SBR and I might even have to throw a can on it!


ETA 1/15/15

I cleaned the rifle after the last trip and went back to the range and loaded up 4 30 round magazines with Wolf poly.

Mag 1: Euro Steel, 30 rounds, NO FAILURES
Mag 2: Polish Polymer, 30 rounds, NO FAILURES
Mag 3: Bulgarian Waffle (Circle 10), NO FAILURES
Mag 4: Magpul, 30 rounds, NO FAILURES.

Note: It was difficult to cycle the first round from the Magpul magazine from a closed bolt. Open bolt...no problem.

Summary: 3 failures to feed in the first 25 rounds. No failures with various mags in subsequent 195 rounds.

I'll be finalizing my Form 1 tonight!

Needs a stamp and a side folder. Noice.

Nice! I just got a gen 2 556R and LOVE it. May have to get one of these too!!

I'll be sending in my Form 1 this Friday!

Will this upper fit on a Gen-2 556R lower?  I'm thinking I want an SBR too and I already have a 556R.

I believe they will.  I tried swapping my 556xi in 556 and it mounted just fine on my gen2 556r lower.

My Form 1 came back last week.

Now if it would just quit raining, snowing, sleeting...I might be able to get it out to the range to zero.

How much does it weigh set up like that?

Dope. Rex Approves.

That looks great!  I really like my Sig 556 SBR - a 556R would be even better!

We need a range report ASAP.

Very nice!  Quick question...What optic mount is that?

I'm still shopping around for an optic for 556xi and I keep going back and forth between a red dot and the Trijicon TA33.

That's a LaRue mount.  

Sick setup, exactly what I envision besides an AR stock collapsable folder (I'm a heathen lol)

I hope range reports are positive, I need to choose between an Xi or the cmmg mutant...

I've taken it to the range two more times without a single issue.

Shooting Wolf Poly out to 200 on steel all day long. Will try it out at 300 in the next week or so once I confirm my zero.

And...with any luck I'll have a can for it by mid-April.

Anyone know what the initial problem was with the 556xi? Was it the same problem they had with the 556R?
The 556R was under gas, also from what I understand, if need a stronger recoil spring, hammer spring and firing pin. I wonder if the 556xi also took these changes?
It just seems as though it wasn't because of the problems they first had with them.