Probably would work better if you could force airflow over it, but there's really no good way to install a fan. I suppose it must help at least somewhat, and it doesn't seem insanely expensive relative to the prices of a lot of other things people put on their guns, especially given that it's a JP product, so...?Originally Posted by Default.mp3
Without using a conducting thermal paste between the barrel and the shield I can see it actually creating a insulating space trapping and reflecting heat back to the barrel making things worse.
I could break out one of my thermal cameras and mess around with various handguards to see how they absorb, reflect and conduct the energy radiating off the barrel... but that sounds too much like work I should be getting paid for.
Last edited by JodyH; 02-20-2019 at 09:46 PM.
"For a moment he felt good about this. A moment or two later he felt bad about feeling good about it. Then he felt good about feeling bad about feeling good about it and, satisfied, drove on into the night."
-- Hitchhiker's Guide to the Galaxy --
That looks like it would be great if the rifle is on a bipod, otherwise it seems the fins would be dissipating heat directly into the hand guard. Unless there's an optical illusion I'm not catching?
Nothing so needs reforming as other people's habits - Mark Twain
Tact is the knack of making a point without making an enemy / Where is the wisdom we have lost in knowledge?
That's the exact reason I spray painted my light green. After leaving a black rifle in an exposed rack during competition, it is night and day how more pleasant it is to handle.
My 2nd take on this is that all the extended, slim rails go hand and hand with mid-gas guns and forward reaching griping of the rifle. If I ever decide to build another AR, it'll likely be a carbine gas gun to move the primary heat maker (gas block) away from where I like to place my hand.
If you look at one with the JP handguard on (see pic), there's a gap and it seems like they've cut the handguard holes to get a lot of ventilation. My 3-gun buddies who've tried the JP thermal dissipator really like them.
Last edited by jbrimlow; 02-22-2019 at 03:21 PM.
The OD of the fins is 1.375" or 1.150" per the JP documents, so depending on the diameter you reprofile the barrel to, it should fit under most handguards.
Source: https://jprifles.com/document_pdfs/T...or%20F_682.pdf
Other forums have reported 20-30 degree F temperature drops with this under handguards, but I'd defer to actually calling JP for real data for a given application.
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