[McE]

So this M&P15 Sport I just got, while it is solely a range toy as my CCW and HD needs are sufficiently met, I have been wondering if I can attach a weapon light to the bayonet lug since it's just sitting there. There aren't any rails on this AR other than the top rail, and the handguard feels like it should remain as a place for my hand.
Are there adapters of some sort or actual lights that easily attach to a bayonet lug? Are these lugs standardized somehow and if so, what are they called or what dimensions/terms should I look under?

 

[jeeper1]

Bayonet lugs vary between different models of rifles and mounting methods. If you want to mount a light on one rifle and swap it to a different model of rifle, such as an AT15 to a M14, forget it.
The easiest way is to spend the money to buy a bayonet then butcher it to mount a rail on it that you can mount a light on. The alternative is to scratch build a detachable mount to go on the bayonet lugs.
Remember whatever you do the light must be totally behind the muzzle or the muzzle blast will remove it.
I have had the muzzle blast from a mini 14 blow a flash hider apart.

 

[youngandfree]

They make an offset light mount that attaches to top rail and positions the light to the side. Or get a drop in quad rail and replace the standard handguard and mount a light to the end of the side rail.

 

[CJS3]

You can get rail adaptors for bayo lug and for the front sight. I've seen both on AR parts sites. This is one marketed by the MAKO group. A bit more than I'd be willing to pay, but it'll give you an idea what to look for.

Bayonet Lug Mount for Tactical Light/Laser - 1" - Flashlight/Flashlight Mounts

 

[darbo]

I did a quick search, this is about the least expensive one I found. Now it is just a picatinny rail but then you would have a rail to attach a light in that area.

ProMag AR-15 Bayonet Lug Picatinny Accessory Rail

 

[AOCM.RET]

Well, ....looks like the answer to your question is no, there is no mount for the bayonet lug. I don't know of any either. Good luck!

I spoke to quickly!!:bang:

 

[McE]

Thanks guys. I went ahead and bought a short little rail section that mounts to the front sight. Downside is I will need a different case to accommodate the added light adding to the width of the AR.
Figured a light on the underside would be prone to being blocked if I have to shoot from behind horizontal cover or get banged up if I have to rest it on something.