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S&W M&P 15 OR mods

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Kinda put the cart before the horse but was wondering if we have any S&W AR owners and if you've done any mods.

I bought one several years ago with they first hit the street but never really intended to use for anything.  I have a couple 870's set up for home defense and way too many special purpose rifles to use it for hunting.

There is tons of info on the net for upgrading and modifying the AR's but almost nothing on the S&W and I was under the impression there was a lot of proprietary stuff involved with it. 

When I first got it, having shot thousands upon thousands of rounds through M16's teaching special weapons tactics in the military, I didn't like the way it handled so I modified the trigger to a 3 1/2 pound pull, changed out the buffer and a few other mods so in rapid fire it recoils straight back without kicking up and added Troy flip up sights.  At 50 yards, you can empty a mag in rapid fire into a 6" circle now.

I recently decided to go ahead and add optics, laser, flashlight, angled foregrip etc, but that's not possible with the OEM handguard.  So, I've ordered a 13.5" M-Lok, free floating handguard and low profile gas block to give me something to mount my add-ons, not knowing if the barrel nut and gas block is standard AR or some proprietary fit from S&W, and they have to be changed to free float the guard. 

Another fun part is I'm left handed and entertaining using a holographic site mounted at and angle beside the 1x scope.  I experimented with it today (first time I've shot it in three years), seeing how that will work and the most natural way for me to roll the rifle to use the holographic site puts the ejection port upward, sending hot brass straight back at the top of my head.   After Pricing left hand uppers or doing a left hand build is not in the cards for now.


If any of ya'll own and have modified the M&P15 OR, any info or words of wisdom would be appreciated.

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......also being a lefty and aware of the limitations of the S&W, that's as far as I would go.

Since I always have a cover, I have just gotten use to it.


That said, all my AR's are history and AK has taken their place. Not nearly as good for distance, but serves my purpose. I doubt I will ever take a 100 yard shot again. If I have to reach out to touch something beyond that, I switch to a very sceary black rifle...

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That's why they make chocolate and vanilla ice cream, or you can get into the Ford vs Chevy debate.  I'm not an AK person.  I know they have way more fire power, just the difference between a 68gr (about as heavy and my 1:9 barrel will stabilize) 5.56 and 150gr (or heavier) 7.62 alone is huge, not counting the extra push behind them, but I have weapons that will provide as much "fire power" anyone could want when I feel that might be needed, and do it very accurately at a very long range.

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No intention to make this AR vs AK

I just understand the trials of being lefty and R eye dominant.

.....that and anymore changes to the S&W will be expensive 

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At least I'm south pawed and left eyed, but can shoot right about as good as left when I have to.  I think that's mainly because I always shoot with both eyes open, even with optics, and do a lot of instinct shooting where I don't even use sights.  Back in 1969 I bought my first and only left hand bolt action, (have over a couple dozen right hand bolts)  and to this day, I can still shoot a right hand bolt faster.  Never have gotten comfortable with working the LH bolt.


As for the AR mods, after doing these updates, about the only thing left I would want to do is a barrel upgrade if this one proves to be not so good.  I've never shot it with optics or off a steady rest for small groups so don't know what it will do for accuracy.

My next AR upgrade will be a custom built AR-10 in a 260.  I ordered a barrel a while back but it usually takes Krieger a long time to make one off's, so that will probably be next year.

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1/2 hour job turned into several hours and that old saying "buy cheap s**t, get cheap s**t definitely held true on the mods. 

First, I had a hellava job getting the role pin holding the gas tube in the gas block out, and I had the right size role pin punch but it was so small and tight, it kept bending my punch.  Also, the pin being slightly smaller than the hole in the block didn't help matters any.

Then the special barrel nut wrench kept slipping over the notches in the barrel nut and wouldn't break it loose.  Finally had to basically destroy the barrel nut and use a pipe wrench to break it loose.  It was very tight and good thing I had the received vise block to hold the receiver.   The new grip came with it's own barrel nut so I wasn't concerned about having to ruin the one on the rifle.

I bought one of those cheap, Chinese handguards and ended up having to clamp it in the vice rather tightly to compress the split grove that holds it and then tighten the allen screws to keep it from moving up and down a 1/4".  The screws had such a soft temper on them, they wanted to round out before you could begin to get them tight.  The reason for that, the front site sits out on the end of it and if it's moving up and down, don't do much good to have the sight.

Also, I should mention I did at least get one with a steel barrel nut, and also, the top rail didn't match the factory rail.  It was slightly lower than the receiver and also the spacing was off so you couldn't have something like a solid scope mount sitting across the joint. The slot spacing was off.

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