How to change an M&P 15 handguard length?

Redrider1 · #1 05-08-2021, 11:15 AM

I recently bought a new M&P Sport 2 in 5.56 and want to change the handguard from a carbine length Magpul M-Lok to a mid length Magpul M-Lok. Can this be done without changing the barrel? I can't find any definitive answers, thanks.

ColbyBruce · #2 05-08-2021, 11:26 AM

You can swap out to this style which is a bit longer but you have to remove your front sling swivel.

Redrider1 · #3 05-08-2021, 02:29 PM

Quote:

Originally Posted by ColbyBruce

You can swap out to this style which is a bit longer but you have to remove your front sling swivel.

How would the new M-Lok handguard mount if its longer since they secure into what I believe is the gas block?

BSA1 · #4 05-08-2021, 03:20 PM

You will need to use a Free Float Handguard which means you will have to remove the front sight base, gas tube and the barrel nut.

Then install the new barrel nut that comes with the Free Float Handguard, a Low Profile Gas Block and a Carbine length Gas Tube. (You can reuse the original Gas Tube which will save you a few bucks). You will need to time the new barrel nut for the gas tube to pass through.

Next install the Free Float Handguard.

If you want to use iron sights then you will need a front sight that attaches to the handguard rail.

With a Free Float Handguard you have a variety of lengths and styles to choose from. The most important thing is to use a handguard that will fit over the gas block.

You will need a few tools so it is up to you to decide if you want to do yourself.

BSA1 · #5 05-08-2021, 03:25 PM

Quote:

Originally Posted by Redrider1

How would the new M-Lok handguard mount if its longer since they secure into what I believe is the gas block?

It is still drop-in Carbine Length.

Youtube is a great way to see how it is done.

ColbyBruce · #6 05-08-2021, 03:35 PM

Quote:

Originally Posted by Redrider1

How would the new M-Lok handguard mount if its longer since they secure into what I believe is the gas block?

As stated above, the two I have in the photo are carbine length mounting compatible but the body is longer.

Redrider1 · #7 05-08-2021, 09:58 PM

Quote:

Originally Posted by BSA1

You will need to use a Free Float Handguard which means you will have to remove the front sight base, gas tube and the barrel nut.

Then install the new barrel nut that comes with the Free Float Handguard, a Low Profile Gas Block and a Carbine length Gas Tube. (You can reuse the original Gas Tube which will save you a few bucks). You will need to time the new barrel nut for the gas tube to pass through.

Next install the Free Float Handguard.

If you want to use iron sights then you will need a front sight that attaches to the handguard rail.

With a Free Float Handguard you have a variety of lengths and styles to choose from. The most important thing is to use a handguard that will fit over the gas block.

You will a few tools so it is up to you to decide if you want to do yourself.

So in other words there's no way to reposition the gas block and site in order to run a mid length Magpul? Free float is the only option

Redrider1 · #8 05-08-2021, 10:01 PM

Quote:

Originally Posted by ColbyBruce

As stated above, the two I have in the photo are carbine length mounting compatible but the body is longer.

Ok that's the SL you have right? I see there's 1 more mounting keyway on the bottom and it's a bit longer but still a mid length SL would be nice. I have a pretty long reach so a carbine length feels cramped but I would like to stick with a magpul

M1903A3 · #9 05-09-2021, 09:37 AM

Quote:

Originally Posted by Redrider1

Ok that's the SL you have right? I see there's 1 more mounting keyway on the bottom and it's a bit longer but still a mid length SL would be nice. I have a pretty long reach so a carbine length feels cramped but I would like to stick with a magpul

One thing you might consider to accommodate a long reach on a short carbine is a forward vertical grip. It might work for you and negate having to do all that work for one inch or so more total length.

Also, a more vertical grip (rear) might keep your elbow down and feel less awkward. I have a long arm span but with a Magpul MOE rear grip and the carbine length MOE forward grip the rifle fits me just fine.

Take a look at this photo. Same rifle, on the top with the original A2 style pistol grip, and on the bottom with a Magpul MOE K2 (I think!) You can see the difference in grip angle and you can think about how that would change your grip on the rifle.

Sent from my iPhone using Tapatalk

ColbyBruce · #10 05-09-2021, 09:43 AM

Quote:

Originally Posted by Redrider1

So in other words there's no way to reposition the gas block and site in order to run a mid length Magpul? Free float is the only option

Correct, due to the gas port drilled into the barrel. The gas block position can’t change.

double-dipper · #11 05-09-2021, 11:50 AM

What BSA1 said.

Mine was horible for accuracey, it wouldent hold 3" groups at 100 yrds from a bench no matter what ammo/weight bullet I shot. So i changed the barrel too.

The front sight post pins on mine were opposing one was put in left to right and the other was right to left.

S&W M&P 15.jpg

Redrider1 · #12 05-09-2021, 01:17 PM

Quote:

Originally Posted by M1903A3

One thing you might consider to accommodate a long reach on a short carbine is a forward vertical grip. It might work for you and negate having to do all that work for one inch or so more total length.

Also, a more vertical grip (rear) might keep your elbow down and feel less awkward. I have a long arm span but with a Magpul MOE rear grip and the carbine length MOE forward grip the rifle fits me just fine.

Take a look at this photo. Same rifle, on the top with the original A2 style pistol grip, and on the bottom with a Magpul MOE K2 (I think!) You can see the difference in grip angle and you can think about how that would change your grip on the rifle.

Sent from my iPhone using Tapatalk

I have the same grip the K2, the rubber is a lot nicer to the hand as far as comfort, once I get the slightly longer SL handguard that may help, im used to full length shotguns and muzzleloaders from deer hunting. But an angled foregrip is also something I have on the way to see if it's more comfortable

Redrider1 · #13 05-09-2021, 01:23 PM

Quote:

Originally Posted by ColbyBruce

Correct, due to the gas port drilled into the barrel. The gas block position can’t change.

Ok I guess that's what I was looking for, this is my first AR so I'm not familiar with their setup, however I'm not new to mechanics and fabrication. Do you know if a longer barrel changes the gas block location?

Redrider1 · #14 05-09-2021, 01:28 PM

Quote:

Originally Posted by double-dipper

What BSA1 said.

Mine was horible for accuracey, it wouldent hold 3" groups at 100 yrds from a bench no matter what ammo/weight bullet I shot. So i changed the barrel too.

The front sight post pins on mine were opposing one was put in left to right and the other was right to left.

Attachment 512517

Thats all it would hold?

cyphertext · #15 05-09-2021, 02:24 PM

You could always put a low profile gas block on to keep the gas system carbine length and then move the original gas block / front sight further down the barrel to make a longer sight radius and to support longer hand guards... aka the dissipator.

Bushmaster XM-15 MOE Dissipator Rifle 223 Remington 16 Barrel Magpul

shep854 · #16 05-09-2021, 05:50 PM

If the gas block is a flat top (lacks the fixed front sight tower), can't a dummy block be attached forward at the current length for a longer handguard? I believe that's what was done with the Dissipator rifles.