I've had this M&P 10 for a year an a half or so, shot it quite a bit but with limited time to get to the range, probably not nearly as much as most others here. I shoot only reloads, the rifle has a Magpul PRS stock, mono-pod, Midwest Industries hand guard, harris bi-pod and cheapest Vortex scope they make (can't remember the name, just ok.. would like to change). It shoots well, I'm the problem-not the rifle. Only seems to like 168 grain loads, more picky than most rifles I shoot.
I've been wanting to change out the flash hider (stock) for a good muzzle brake. Still not sure which one and will keep checking here for ideas. Can't spend a fortune but want something decent.
That means taking off the flash hider. Turns out I had the same problem a lot of folks have, getting the original one off. It would not remove with normal means (proper wrench etc...). So here's what I ended up doing, maybe it will help someone, I'm no gunsmith but there are so few around I wouldn't know where to go in my area so end up doing most everything myself.
Here's what worked for me, hopefully you guys won't find too many things I did badly enough to destroy what is a fairly nice shooter....
1. With the barrel pointed down a bit I sprayed PB Buster on it several times over a 2 day period. Kroil would have done the same thing, maybe even a bit bettter but that's what I had on hand. Aimed it right at the crush washer and just let it soak. Patience. Not the easiest part but a necessary one...

2. I needed to hold the barrel firmly to get any torque on the flash hider. Being lazy, I decided to try it without removing the handguard. This left a short portion of the barrel to grip. I made up a block of hardwood and drilled a 5/8 inch hole in the block on the drill press and then cut it in half, through the hole, on the band saw. This gave me a reasonable barrel clamp, probably ok for some other uses as well.

3. Once I was pretty sure the PB Buster had worked into the threads about as well as it could I got out my Map gas and torch and got ready to heat the flash hider... this one has a particularly nice tip, the flame is quite concentrated and easy to control.

4. I set up the upper and barrel (should have taken the bipod off but, lazy, as already mentioned....) I slipped the wood barrel blocks around the exposed part of the barrel and clamped the whole thing in a large vise. Kind of an odd look but it was firmly held in place and not moving. The blocks did not leave any marks on the barrel and yet held it securely.

5. I found a 22mm wrench to be the perfect fit for the flash hider. I grabbed it securely and gave me a positive purchase on the flats provided on the hider. Then I applied heat for 20 to 30 seconds. Just enough to see the PB Blaster start to vaporize out of the threaded area, also ensuring that it was down in there where I needed it.
6. This next one may be the trick that helps the most. Having worked on my share of cars and stuck fasteners you learn that to remove a seemingly stuck bolt, you first give it a bit of tightening. It's completely counter-intuitive but it must have something to do with helping the threads begin to release or breaking some corrosion on those threads. Give it a fairly firm pull in the direction that would tighten it and then immediately try to loosen it. Mine came off fairly easily once I followed all the steps above. And it was really on tight.
7. Had a close look at the crown and threads and all seemed pretty clean, this photo was taken right after the hider was removed. I think the barrel should give me some more use, good as I'm not sure what I'll do when this one gets shot out....


So any ideas on a good muzzle brake would be helpful, I've always been partial to the smooth look of one that matches the barrel diameter but that's not critical.

Hope some of these ideas were helpful, it worked for me and the rifle seems to have survived.
Best
Bruce

I use a seekins precision on my mp10, works great! got it on ebay for 50.00

This article might help you narrow down what you might want. It's a bit on the old side but should still give you a good place to start.

.30 Caliber Muzzle Brake Shootout - The Truth About Guns

How much you want for the stock flash hider

I often use the M&P10 from a bench supported position at longer range steel targets. The rifle recoil makes it difficult to spot my shot, whether from sand bag or with tripod.

I saw this thread and decided to have a go at removing the flash hider and installing a midwest Industries muzzle brake. Using aluminum gun smithing v-blocks in my vise, I wrapped the forward part of barrel with leather, and tightened in the v-blocks. The oem flash hider was not overly tightened and came loose with minimal torque - and I do mean minimal torque effort.

I installed the brake using a jam nut, with a magnetic bubble on the gas block to make sure it was clocked pretty close. It was easy peasy. Thanks for starting this thread, the information was good.

Now I can see my shots going into the target ... or ground. The MWI muzzle brake is the three hole type and is only about $30 on line. Could spend a whole lot more installing, for instance, a JP brake, but not sure one could practically notice any difference.