I saw an ad for a Sig/SAN 550 and got curious as to how these rifles stack up to todays modern offerings? Simply quality wise, I understand there are more M4 parts/mags etc out there. I'm curious about these vs say a B&T APC223, SCAR, ACR, AUG, XCR etc. I've always been impressed with the STG90 testing and wondered if its one of the best of the past or still a great contender today.

Having owned multiples of Swiss 55x, SCAR, AUG, FNC, ARs (Colt, KAC, LMT, LaRue), and with lots of time behind the entire B&T line, I can say without hesitation that the Swiss 55x series is the highest quality production 5.56 fighting rifle in existence. There is no contest.

If discussing the utility, it’s hard to say anything beats a top tier properly kitted AR15.

If strictly basing it on quality of manufacture, the Swiss SIGs win.

I have a Swiss 551, I think it's just as nice, maybe nicer, than my FN FNC, and Beretta AR-70.

There's no doubt that the Sig 550 (and 55x) rifles are well built. Flawless function, and the few I've handled show amazing fit and finish.

Higher-end AR-15s exhibit flawless function, and they can have really really high quality fit and finish. Some may even match that of a Sig 55x.

My AR-15s are all scratched up from general shooting, transportation, training, and especially competition. Fit is still flawless, but finish.....not so much anymore. The only cycling issues I have experienced were from instructor-induced-jams and defective magazines. I remember the instructors' lessons and I tossed the bad mags.

After cycling reliability, I demand great accuracy from my ARs. All show 100-yard groups of .6" to .8" with multiple factory ammo types. My best ARs will do .4" to .5" groups when the stars align properly. All produce sub-MOA accuracy out to at least 500 yards. I have not yet heard of this level of precision consistently coming from Sig 55x rifles. So yeah, IMO the Sigs stack up well to modern high-end ARs, but not quite.

B&T APC223's have been cracking bolt carriers. I've heard of the same issue on Swiss SIG's over in the sandbox but no idea what those duty cycles were like.

I've got five B&T's, three FNC's, several pre-ban Colts, Daewoos, Armalites, etc. My two 550's, 551-2SP Swat and 553's rank up there as tops in my collection. I'll be after a Beretta AR-70 next so can't compare just yet.

The 550 rifles are no doubt among the finest. If you have the coin, go for it. There is no reason not to buy one.

How do they stack up among the rifles you mentioned? How do you stratify the cream?

I've not had a proper shot at purchasing one, but I've pulled a trigger. I've shot a lot and and own a few of the rifles mentioned.

Just buy that 55x.

Any issue with mixing and matching? It looks like there are upper and lowers available but not complete rifles which actually helps in my state. Anyone run one suppressed? Thanks for the help so far.

quote:

Originally posted by PGT:
B&T APC223's have been cracking bolt carriers. I've heard of the same issue on Swiss SIG's over in the sandbox but no idea what those duty cycles were like.

I've got five B&T's, three FNC's, several pre-ban Colts, Daewoos, Armalites, etc. My two 550's, 551-2SP Swat and 553's rank up there as tops in my collection. I'll be after a Beretta AR-70 next so can't compare just yet.

Only the 552 was known to have issue with catastrophic carrier failure. And it was supposedly limited to a bad batch of heat treat. The design of the piston-carrier interface on the 552 leaves much to be desired. The piston can move ever so slightly and the locking lug on the piston can become peened, then ultimately result in failure of the carrier at the rear in the channel for the piston’s locking lug. The 553 is the solution for this design problem. I have never heard of a StG90/PE90/550, 551, or 553 suffering such a failure. I’d be interested to hear from some of our Swiss members with more high round count experience. I emailed Ron Cheney from Battlefield Vegas a few years ago asking about the durability of the 55x series. At the time they had Swiss 553s and US 556s that had 60k’ish and 100k’ish rounds on them, respectively, with only recoil springs needing replacement at some intervals.

quote:

Originally posted by Anubismp:
Any issue with mixing and matching? It looks like there are upper and lowers available but not complete rifles which actually helps in my state. Anyone run one suppressed? Thanks for the help so far.

No issue mixing/matching uppers and lowers. Re: suppressed use, if you want to use one on a 550 or 551 you’ll need a Gemtech HALO or the AAC Omni that attach to the integral flash hider or M16A2 flash hider. JDI did import a limited number of 551 short uppers with threaded barrels, but good luck finding one. Or you’ll need a 552/553 with removable flash hider. The 552/553 short barrel (8.9”) won’t allow removal of the gas tube (gas valve can be removed, but not the gas tube)with most contemporary suppressor mount muzzle devices (SF SOCOM, AAC, and DeadAir to name a few). The A2 flash hider and KAC NT4 flash hider will alllow removal of the gas tube and I suspect the KAC 5.56 QDC mount will as well if the indexing pin is positioned properly. Also the 55x series is very over gassed. There is a 552/553 4-position gas valve that has a reduced port size for use with a suppressor. The 552/553 valve’s inner diameter is smaller than that of the 550/551/556, so the 552/553 valve cannot be used on its bigger brothers (559/551) or cousins (turd burgled 556 series).

quote:

Originally posted by JoshNC:

quote:

Originally posted by PGT:
B&T APC223's have been cracking bolt carriers. I've heard of the same issue on Swiss SIG's over in the sandbox but no idea what those duty cycles were like.

I've got five B&T's, three FNC's, several pre-ban Colts, Daewoos, Armalites, etc. My two 550's, 551-2SP Swat and 553's rank up there as tops in my collection. I'll be after a Beretta AR-70 next so can't compare just yet.

Only the 552 was known to have issue with catastrophic carrier failure. And it was supposedly limited to a bad batch of heat treat. The design of the piston-carrier interface on the 552 leaves much to be desired. The piston can move ever so slightly and the locking lug on the piston can become peened, then ultimately result in failure of the carrier at the rear in the channel for the piston’s locking lug. The 553 is the solution for this design problem. I have never heard of a StG90/PE90/550, 551, or 553 suffering such a failure. I’d be interested to hear from some of our Swiss members with more high round count experience. I emailed Ron Cheney from Battlefield Vegas a few years ago asking about the durability of the 55x series. At the time they had Swiss 553s and US 556s that had 60k’ish and 100k’ish rounds on them, respectively, with only recoil springs needing replacement at some intervals.

Josh, weren't the few 552 BC failures limited to high round count select-fire carbines?

There is no evidence of ruptured bolt carriers in Stg/PE 90´s in Switzerland.
Know was premature barrel wear with early GP90 ammo but this problem has been solved with different jacket material.
Another obervation are cracked receiver near in the foreward section on the LH side, close to the barrel block. Out of 38000 rifles the Swiss DoD refurbished, 410 rifles had been discovered to show this failure. The DoD tested the rifle and announced the result to the Swiss sports shooting association and their insurance. The rifle is still good to go even though the receiver was demaged. The issue is know in the shooting community and had been accepted without any uproar.

quote:

Originally posted by Modern Day Savage:
Josh, weren't the few 552 BC failures limited to high round count select-fire carbines?

No idea on round count or FA vs semi use. The only discussion I recall was a private military contractor from Canada who’s team had 552s in Iraq and reported the failures.

I can say that all 552 carriers from demilled parts kits that I’ve had (3 or 4) had peening of the piston’s locking lug. My 552 semiauto LE-trade in does not have this, but it looks to have been used very little.

confirmed with said contractor it was only 552's.

quote:

Originally posted by PGT:
B&T APC223's have been cracking bolt carriers.

Do you have any additional info on the B&T bolt carrier issues? I was considering a B&T 308 DMR, so this is a bit disconcerting.

I believe it's a surface crack. Improper hardening maybe? I'll see if I can dig up a pic.

edit - here you go

Thanks for looking into that PGT! I hope they iron that out.

The problem with the 55X-series is that they are not as easy to upgrade with light, optics and so on.

Otherwise they are top notch, but they are on the heavy side.

Right now I have to decide which rifle to take to a one week shooting course on distances out to around 450 meters.

Have not yet decided between the AR15 with 10,5" bbl, the 553LB or the 551LB. All have an Aimpoint mounted and a suppressor.

quote:

Originally posted by Kampfhamster:
The problem with the 55X-series is that they are not as easy to upgrade with light, optics and so on.

Otherwise they are top notch, but they are on the heavy side.

Right now I have to decide which rifle to take to a one week shooting course on distances out to around 450 meters.

Have not yet decided between the AR15 with 10,5" bbl, the 553LB or the 551LB. All have an Aimpoint mounted and a suppressor.

It’s hard to beat a properly kitted out top tier AR15. It’s the most ergonomic and most readily configurable contemporary rifle design. I love my Swiss SIG 55x rifles. But if I had to use a rifle for social purposes, the AR would be my choice.