A regular M68A1 doesn’t have a muzzle brake on an M1 or IPM1, simply because a 27-ton recoil isn’t a problem for a 70-ton tank. Because it has no muzzle break, most of the overpressure from the main gun goes forward — provided you cover your ears and wear protection for your eyes, a single 105mm shot from an M1 won’t injure you if you’re on top of it or next to it.

The MGS, however, uses a “Pepperpot”-style muzzle brake, which the “breechblock incident” demonstrated it cannot operate without. One of the side effects is a more destructive muzzle blast.
This article is old, but the MGS’ muzzle-brake dilemma simply can’t be fixed without replacing the M68A1 with an entirely new main gun — the laws of physics don’t go away over time, contrary to the “Dated Information” Fallacy popular among Stryker apologists;
http://www.g2mil.com/Stryker.htm

I don’t know if I suffered permanent hearing loss but my wife says I never listen.

- Notice that no one EVER stands within 1000 yards of an MGS while it fires? They’d suffer permanant hearing loss if they did.
- If you stand within 100 yards of an MG muzzle blast, you will DIE from overpressure — no thanks to the pepperpot muzzlebrake.
- an attempt at firing the 105mm gun without the muzzle brake resulted in the breechblock smashing through the autoloader on the very first shot.
- GDLS contracted-out the design and construction of the MGS’ autoloader to Aries, who had no expeience with such technology — the result was that the MGS’ autoloader jams on every 4th shot.
- Any jamming or stoppage in the gun or loader requires partial disassembly by hand, done by crewmen standing skylined and totally exposed atop the 8-foot-tall MGS.
- The COAX machinegun is not fixed to the gun like those fitted to tanks, and requires frequent re-zeroing as an inescapable consequence.
- The COAX is also fed using a complex, delicate, and jam-prone type feeder which the M240 was NOT designed to be able to feed from.
- The M2HB on the roof can only be fired by an exposed VC, and can only aim over the frontal arc. At least one VC was nearly killed by a sniper as a result.
- The so-called “Low Profile Turret”, as you can plainly see, is actually just a gun in an armored sleeve sitting atop a pedestal, and is thus not a turret at all — it isn’t low-profile, either.
- An empty, stripped-down Stryker MGS weighs 25 tons, and the chopped-up (and thus now more delicate) MOWAG Piranha suspension underneath was designed to support only 12 tons continuously, and 15 tons for short periods.
- Add the 7500lb (3 3/4 ton) “Birdcage Armor”, and an empty MGS now weighs 28 tons. Add a 1 ton of ammunition, fuel, a half-ton of gear, plus a half-ton crww, and you get 30 tons.
- 30 tons atop an 8×8′s footprint of 8 square feet = 62psi. That’s FOUR TIMES as much as the crushing 15psi ground pressure of an M1A1 Abrams, and enough pressure to set-off any pressure-fused mine.
- Only two axles on each Stryker are configured to accept run-flat tires, and only 2 MOWAG axles will instantly SNAP under 25 tons.
- In order to manage the recoil, the 105mm shells are filled with half-power propellant charges in order to reduce suspension damage, turret wear, and the likelihood of a flip-over. not that is works when the turret is traversed 90 degrees;
http://www.youtube.com/watch?v=0g-Wk3FZL6I
- Ever see a video of an MGS firing over 90 degrees on an incline, or @ 45mph, like GDLS and the US Army claim it can? You never will.
- Watering-down the power of the charge results in virtually unpredictable accuracy — notice how close the MGS always is to the target in all these videos?
- Watering-down the charges also results in a high dud rate, as demonstrated here; http://www.youtube.com/watch?v=fBHnNSURLEA
- The half-power charge also results in perfectly useless APFSDS rounds, because propellant charge power is what makes Sabots work.
- The MGS costs $4.5 Million — the same as an original M1A2 Abrams, and nearly 3x as much as the 8-ton lighter M8 Armored Gun System that was rejected in favor of the MGS.
- The 105mm M68A1 is a high-recoil-force gun with 27 tons of immediate recoil (it was, after all, designed with a 50-ton MBT in mind — never anything lighter). It’s a gun too powerful for an Armored Car, fitted to an Armored Car too weak for a large-bore gun.
- GDLS didn’t use a low-recoil-force gun on the MGS, because it would have compromised their parts monopoly on the Stryker — and they happened to have some left-over M68A1s that they didn’t have to spend any money buying or building (never mind that it puts 27 tons of recoil against a 25-ton Armored Car).

…and that’s only a sample of what’s wrong with the MGS…

Here’s my fave YouTube footage of the beast at work:

http://www.youtube.com/watch?v=48qH64uvx_U