And with that being said, step up to the fountain of knowledge...... Note the level of detail.
The SA80 is a poor design and prone to a lot of problems. The M16/M4 isn't superior in ALL regards, be it is in MOST of them
When dudes raised on the SA80 switch over to M4s (and even the M16A4 fence-post) they love them, especially when I show them the versatility of the system.
It is heavy. It feels like an AK, weight-wise. It is primarily constructed from stamped sheet metal.
The trigger has serious issues, and under a heavy firing schedule are prone to failing. I have personally seen three guns go down almost simultaneously with the same problem.
The handguard has a mounting screw that goes through the gas-block on the barrel which makes the gun very susceptable to POI change due to pressure on the handguard from aggressive hold, VFG use, or supported positions. This is not changed with the DD handguards- which have their own problems. They are prone to loosening of the retention screws (one through the gas-block and one that presses into the front of the receiver), which results in drastic POI variance. The gas block is exposed, and it happens to be right where the support hand wants to be for good front-end control. The top rail is lower than the top of the gas-block which severely limits a 12:00 light mount.
It is highly trigger sensitive and prone to having consistently low groups during rapid fire or rapid trigger manipulation.
It is no more accurate than an M16 or M4 when compared with similar optics.
The line of sight over bore is really high, especially when using a piggybacked MRD.
The NATO rail is severely lacking.
The SUSAT is a nightmare.
I have not seen the magazine well bend. However, I have seen what we would call the "lower receiver" (TMH here) bow outward which results in the magazine over-seating (like crappy 10 round 1911 mags do) during speed reloads.
The weapon can be fired left-handed, but only if you are very very careful and have a laser.
The rearward weight distribution makes the gun bouncy during multi-shot engagements and auto. I can hold 20 rounds on an IPSC on FA (full auto)with an M4A1, about 10 to 12 with the SA80.
The lack of adjustability of the LOP (length of pull) makes the gun sub-optimal for CQB. Everybody touts the thing for being so short, but the LOP is barely shorter than an M16A2. Combined with the zero amount of eye-relief of the SUSAT; CQB work with it when wearing armor sucks unless you want to rely solely on the laser (if you get one) or until the ACOGS come in (which have a MRD piggy-backed). The long LOP prevents the 3-man from carrying in the high port, which results in a less than speedy 3-man's gun in the room/fight.
It is virtually unusable with a single-point sling though the issue 3-point essentially configures into a single point, it isn't really. The sling sucks hard, but that will probably be a non-issue since we do have options.
The pistol grip is uncomfortable unless, get this, you hold it with all of your fingers. That's right- it's more comfortable to carry in a non-firing grip than with a finger straight and off the trigger.
The position and type of safety requires the shooter to use the left hand to engage the safety. It's a cross-bolt safety just forward of the trigger guard.
The mag catch is stiff and only operable with the left hand.
The placement of the mag release and charging handle (left side and right side, respectively) means that you have to flip the gun back and forth for stoppage reduction instead of just canting it and running it. The bolt-catch is handy though. Unfortunately, the bolt release is tiny and requires a bit of dexterity to consistently manipulate it.
The short handguard makes it impossible the grip out on the rail where you are most efficient, but you have to hit the safety with the left hand anyway, so it's just a forced compromise anyway. It feels like a pan of water during SOM (shooting on the move).
The trigger mechanism is slightly less complicated than the interior of a combine harvester, and prone to all kinds of fouling and unnecessary play, resulting in a great trigger (sarcasm).
The buttstock is ribbed, but doesn't stick in place during firing like a decent stock should. It is also heavily curved which makes running in the frontal pocket with armor more difficult than it needs to be.
You need two hands to work the gun and a functioning right side hand, arm, and clear line of sight to the right eye. This implies a lot of of failure points when in unconventional positions.
I taught the lead urban combat course in both marksmanship and tactics in the UK to instructor-level personnel from everywhere from SFSG to FPGRM. To a man they are senior and all have multiple tours in Iraq and the 'Ghan. I work with senior guys, guys that have been around and done stuff, many of which carried weapons systems other than the SA80. All of them are vocal about the fact that the SA80 needs to go away and be replaced with something that is actually made to fight with.
Yes, we are using A2s. There are no A1s, as they were all upgraded to the A2 configuration. Yes, I know the difference.
The SA80 is a bit better with the ACOG, but it doesn't do a damned thing about the problems with the system. The mount is a weak point. The ACOG needs to be cantilevered forward with the mount due to the rail being too short, and there are numerous accounts of a dropped rifle breaking or bending the mount. Implying that system would be fixed with an optic is grasping for straws and trying to obscure the real issues.
I have sufficient experience in CQB to say that the short overall length of the SA80 is not an advantage over an M4, especially considering that the length of pull is not adjustable. Most movements within the enclosure will be done from a compressed position with the barrel pointing either upward or down. Virtually no actions will be taken with the gun up unless covering a danger area or threat, in which case the shorter OAL does nothing. Indexing the gun sucks since the bolt travel will cause the cocking handle to strike the bicep if brought into an under-arm position, which means that I can actually make the M4 protrude a shorter distance and still be usable for extremely close contact. I have hopped into and out of vehicles a few times and I can positively say that the SA80 is barely better than a SAM-R (USMC's version of the Mk11 SPR essentially), and no better than an M4 in those conditions.
Why can't people be honest about things like guns? The SA80 is a POS. A better gun backed by better training would yield a better result. Why don't people want that to happen? As it is, HK is running out of SA80 receivers (I forgot to note, they are prone to cracking), which means that the MOD (Ministry of Defense) will have to accelerate their selection of a new system. I know this because I was in a tri-service (British) meeting about the topic.