AR 15 heat shields

[taliv]

so what's the deal with m4geries?

Heat shields were pretty popular, for good reason, with the old A2 style hand guards, but they've completely disappeared with the new free-float and quad rail forearms everybody's using.

I have a YHM quad rail on an RRA upper, with low-profile rail covers, and I can't run two magazines through it before i gets too hot to hold. touching the fold-down iron sight on the front gas block gives a 1st degree burn, in less than 2 seconds. Basically, everything forward of the mag well gets almost as hot as the actual barrel on an older style A2.

So, I called RRA and they said... no one had ever asked about that! They suggested I call YHM, so I did. They said they didn't have a solution, but would consider my suggestion to make a heat shield for their forearm. They said nobody was complaining about it.


Am I the only one shooting the AR? are all the mall ninjas just collecting them? surely someone else has this problem.

I asked this question on AR15.com and got no response.

(btw, i don't want to put a vertical grip on)

 

[Onslaught]

Simple... Don't use low profile rail covers... (I assume you mean the "ladder panels") Your fingers still touch the aluminum.

I use the MagPul XT panels on my Daniel Defense 9.0 and don't have ANY problem at all, and I usually run a full can of GA Arms (500 rounds) through one or two rifles when I go. I'm sure TangoDown or KAC would work too. I actually only use the panels at 3:00, 6:00, and 9:00 and a ladder panel at 12:00. I figure it might let more heat out the top.

KAC puts heat shields in their non-FF models, and I think SureFire might, but for the most part I guess it hasn't been a problem.

Another thought... Is your YHM quad rail the original type with just the slots in it for venting? If so, I would imagine that it retains a lot more heat than most forends. My DD rails have BIG holes all around for more venting. Of course, if you have the YHM "ultralight" version, never mind that idea because your rail has even bigger holes than mine

(you'll get all this and more on ARFCOM).

 

[444]

The reason no one else is complaining about it is because they ARE using a vertical foregrip.

 

[Jeff White]

My KAC RAS has heat shields. You might try some rail covers over your unused rail and see if that helps. TangoDown makes some good rail covers. Of course it doesn't look as tactikewl if you cover the rails.

Jeff

 

[Bartholomew Roberts]

Hmmm, can't say I ever experienced that problem on any of my free-float tubes. The Knights FF rail had their 11-rib and 9-rib panels on the unused portion of the rail which protected my hands quite well. Even without the panels, the rails never got too warm during classes with heavy shooting.

The Knight's system regularly ran cooler than my M4 handguards - probably because it was better ventilated and shed heat faster. Only once did the rifle ever become too hot to hold and I didn't even fire any rounds through it - I just made the mistake of leaving it uncovered on an exposed firing line during a hot Texas summer and by the time I came back to the 500yd line after checking my target, it was too hot to grab hold of.

I also have a Daniel Defense with ladder panels and it handles heat very well so far, though I haven't been able to give it a really good test yet.

Generally my experience has been that the well-ventilated FF rails handle heat better than the double-heatshield M4 handguards. I haven't done sustained shooting with the YHM handguards; but ventilation is a big key. If the YHM do not have holes for ventilation (or have little area devoted to that), they may well heat up faster. However, I suspect the real problem is probably sunlight and not rounds fired.

 

[Cesiumsponge]

Hmm, I never noticed my rail system getting too hot to hold. I run a Samson MFRS-R rifle length system on a 16" heavy barrel with a front folding sight (not gas block). The Samson has a lot of ventilation holes in it. I have a few Tangodown rail panels on the sides and the "ladder covers" on the bottom. I took it out this weekend and bumpfired a magazine (just to see if I could do it with an AR) in an unusually warm 90 degree day. I had no problems holding a vertical grip or the rail itself during firing or afterwards. The only thing that seems to get hot on mine is the barrel itself and the flash suppressor. The barrel melted part of some 550 paracord when I set it down carelessly in the trunk; brain fart.

 

[TechBrute]

One of the members here that I shoot with ran a DD rail with no panels for exactly one outing before we both realized that it got hot FAST.

The ARMS SIR handles it well, but the bottom is plastic so it's not a good comparison to the DD, KAC, or LT.

I also run a LT 9.0, and I shoot it with Magpul panels on it. I have no idea how hot it is without them, as I had them on from the first shot.

 

[Cesiumsponge]

I just wanted to note the Samson/Troy rail systems mount to the barrel nut but doesn't actually replace it with it's own. It requires no real gunsmithing. One removes the handguards, cuts off the delta ring, the snap rings, and the rail snaps on and mounts to it. The contact area might be less than the other designs which would lead to less heat transfer and would explain why I did not experience overheating, plus I used a rifle-length rail system.

 

[taliv]

ok... so I have the YHM "quad rail" which is not the ultra light, but it does have vents.

Here are several pics of the gun (and my lovely dining room table...) (i know they're a bit large)

again, i'm well aware that i can either put a verticle grip or larger rail covers on there. I'm not opposed to putting a larger rail cover at 6 o'clock, but what i'd really like to do is solve the problem by putting a heat shield in all that space between the forearm and the barrel, so the forearm never gets hot in the first place.

even so, i appreciate all the feedback

i'm not actually using the 'free float' on this, as my sling is still attached to the barrel, although i guess most of the load really is on the forearm. so doing something that results in it no longer being FF won't bother me.


This is the ++pimp tacticool version with all the naughty bits attached:

This is minus NV scope

this is the forearm in question from side and top

finally, from rear using BUIS or red dot

 

[Cesiumsponge]

Do you have the old heatshield that came with the plastic handguards? You can try rigging something up underneath but considering it's still all metal, and metal being a good conductor of heat, it might still get hot for your hands. It is hard for me to say if most of the heat is transferring through the barrel nut or it's convection from the barrel itself.

You can try installing thermal insulation (seen the stuff before for engine bays) between that and the rail system, but that would make me nervous in how much heat the barrel would be dissipating.

By the way, what laser setup is that? I'm not familiar with the make/model. Did you mount the YHM front folding site on the gasblock backwards because it won't flip down and clear the rail system when "properly" oriented?

 

[taliv]

heh, yep, i tried really hard to mount it 'properly' and it just won't fold down because the gas block rail isn't long enough. the forearm top rail is in the way. it works fine like that though.

the laser is IR with an IR illuminator on the lower-left. (the illuminator is unfortunately blocked by the sling, but that's no big deal as the nv scope has an illuminator also.) the laser works very well, but i don't actually know who made it. it says "made in belarus" on it though. i got it used. I had a discussion with 'victor' over on ar15.com about it. his friends are building IR lasers using this same housing, but the internal components are different. i think he's selling them if you're interested. i posted pictures in the pinned "lights and lasers / IR lasers" thread over there showing the view from the NV of the laser and illuminator. it's pretty spiffy.

the complete upper was pre-built by RRA so i didn't ever get a heat shield. i could try to find one at the next gun show though. i had strongly considered filling the area between the tube and the barrel with some insulation foam or something, but i figured it would burn.

I'm sure the heat is radiating off the barrel, and not coming from the barrel nut. I think what i'm going to try is getting a sheet of neoprene and attaching it to the inside of the tube.

the reason i have an aversion to learning to use a verticle foregrip is because i'm left handed, and find it very ergonomic to shoot the irons properly, then cant the rifle 30 degrees or so to the right which perfectly aligns my left eye (dominant) with the red dot. with the magpul stock, my cheek weld doesn't change. however, i don't think the verticle foregrip would be comfortable with a 30 degree tilt, especially for long periods of time.

 

[TechBrute]

You don't need to use a VFG.

I'd still just suggest using proper rail covers like they were designed. The rail covers insulate as well as protect the rails.

 

[Bix]

I have a YHM lightweight tube on my RRA upper and it gets too hot to hold after moderate use.

Tango Down rail covers solved the problem. They remained comfortable to touch throughout a two-day carbine course earlier this month (although, I spent most of the time with my support hand on the magwell, anyway).

 

[NMshooter]

My LaRue forend with MagPul XT rail covers is a better handguard than the original plastic with aluminium heat shields.

Less heat.

Never understood why anyone would want to leave any of the rails bare either...