Hoping to benefit from anyone's experience. I am currently building a 6.5 cm using the JP barrel kit. I see the thermal dissipator is an option. Looks cool but not sure if I need it or not. I understand the concept but my thoughts are it may interfere with harmonics of a free floated bbl. Anyone using or have an opinion? Thanks in advance
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Anything will 'interfere' with harmonics on a free floated barrel. By that, I mean the harmonics will be different with and without whatever the additional component adds. That does not mean the difference will be detrimental. It may just as well be an improvement.
I did a couple of lookups on the JP Thermal Dissipator, including the Shooting Illustrated review on the JP rifle (.223 Wylde) from 2014. While I can't speak from personal experience, it sure looks like the reviewer's experience strongly favored the option.
I've been paying a lot of attention to barrel heating and cooling for a number of years. Barrel heating concerns have kept me shy of a couple of projects that had occurred to me. For instance, I would be pretty interested in trying a .22-250 barrel that included the Dissipator option. Same interest in a 6 XTC.
This feature had eluded me until now. I think it's worth a try.
Greg
I did a couple of lookups on the JP Thermal Dissipator, including the Shooting Illustrated review on the JP rifle (.223 Wylde) from 2014. While I can't speak from personal experience, it sure looks like the reviewer's experience strongly favored the option.
I've been paying a lot of attention to barrel heating and cooling for a number of years. Barrel heating concerns have kept me shy of a couple of projects that had occurred to me. For instance, I would be pretty interested in trying a .22-250 barrel that included the Dissipator option. Same interest in a 6 XTC.
This feature had eluded me until now. I think it's worth a try.
Greg
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I have a couple POFs that the "oversized barrel nut heatsink" and they are very accurate. I hear JPs are very accurate also. I don't think the heat sink will affect the accuracy enough to matter.
When my boss and my brother bought JP's in 6.5G they where told by the JP people it wouldn't be worth it unless they really planned on hosing some prairie dog towns. Nothing detrimental to accuracy, just unnecessary weight for most types of shooting. My brother was frugal enough to forego the dissipator, my boss had to have it to one up my brother...
Both guns shoot the same with Hornady factory ammo..
Both guns shoot the same with Hornady factory ammo..
I had to look up this thermal dissipator, hadn't heard of it before.
So, it's just heat sink fins that fit around the barrel. Interesting idea, and no real downside except cost and maybe weight. A couple things about that from an engineering point though (I'm a mechanical engineer, heat transfer is part of what I know); it's a decent idea but could be better:
- The efficiency of any heat sink is hugely impacted by how well it contacts the part it needs to cool. I don't see any mention of JP doing this, but if I were to use one, I'd put plenty of heat transfer paste between the dissipator and barrel. This is the same thing as installing a heat sink on a computer CPU; all those computer geeks know to do this, I'm surprised JP doesn't mention it.
- The other part of cooling with a heat sink like this is airflow and radiant heat. JP's handguards, ironically, are one of the worst I've seen for both; they're thick and cover a lot of surface area, trapping radiant heat and blocking air flow. A more open handguard like one of the more modern designs should work a lot better.
One could remove half the height of those cooling fins, and with a more open handguard still have a better cooling system that weighs less.
So, it's just heat sink fins that fit around the barrel. Interesting idea, and no real downside except cost and maybe weight. A couple things about that from an engineering point though (I'm a mechanical engineer, heat transfer is part of what I know); it's a decent idea but could be better:
- The efficiency of any heat sink is hugely impacted by how well it contacts the part it needs to cool. I don't see any mention of JP doing this, but if I were to use one, I'd put plenty of heat transfer paste between the dissipator and barrel. This is the same thing as installing a heat sink on a computer CPU; all those computer geeks know to do this, I'm surprised JP doesn't mention it.
- The other part of cooling with a heat sink like this is airflow and radiant heat. JP's handguards, ironically, are one of the worst I've seen for both; they're thick and cover a lot of surface area, trapping radiant heat and blocking air flow. A more open handguard like one of the more modern designs should work a lot better.
One could remove half the height of those cooling fins, and with a more open handguard still have a better cooling system that weighs less.
I have a rifle on order from JP. As another ME, I don't see the downside. It'll certainly keep the barrel cooler, and may well improve life. Since JP thermo fits their barrels, a barrel change necessitates sending it back to them. Anything I can do to prolong barrel life is money and hassle saved.
I dont intend to carry this gun very far, so increasing weight, for me, is a plus.
I thought i read read or heard somwhere that they are glued on as well, but now I can't confirm it. Must have dreamed it.
I dont intend to carry this gun very far, so increasing weight, for me, is a plus.
I thought i read read or heard somwhere that they are glued on as well, but now I can't confirm it. Must have dreamed it.
Heat will destroy a barrel as fast as anything. If your gonna pony up for a jp barrel it seems foolish not to get the heat dissipator. I have 2. One in 223 an a 6.5 creedmoor build I did using their barrel kit. They shoot fantastic. The weight difference is compatible to having 10 rounds in the gun or 7. Worth it to me even if just for piece of mind.
I have two complete JP builds and have the dissipators on both of them. Are they necessary? I'm not certain. What I am certain of, is that JP knows exactly what the hell he's doing and if he developed the dissipator and says it works, I'm gonna run it.
Both rifles are extremely accurate.
Both rifles are extremely accurate.
Whatever the book max was for 8208 with the 123gr Amax's duplicated the factory loads in the 18" JP barrels. Tried going slightly past book max and accuracy suffered a bit, brass suffered more and speeds didn't really increase.
As I mentioned previously , i have 4 JP rifles with heat dissipators. I'm pretty easy on them. I don't use them in a 3 gun type setting. I shoot long range steel, and predator/hog hunting. One to three shots most of the time. So honestly i dont need one.
So why do i have heat dissipators, because I own the hightest quality, best looking brand of AR's on the planet. The colored heat dissipators add beauty and a cool factor to the rifles.
So why do i have heat dissipators, because I own the hightest quality, best looking brand of AR's on the planet. The colored heat dissipators add beauty and a cool factor to the rifles.
Interested to know as well. This was the only part of JP upper I didn't get along with the hand guard for my lightweight build
I've had a fair share of JP rifles (4 LRP-07's in 308 and 6.5cm, SCR-11, JP15) and they've all had thermal dissipators on them. While I haven't done any actual tests on increased cooling, I've not had any problems with the thermal dissipator causing accuracy issues.
I have a JP Barrel in a 6 Creedmoor and the thermal dissipator; have always had it on so no comparison running with vs. without. I do notice the hand guard is warmer than other ARs I have... Accuracy is pretty good, don't know how it would get better.... 107 SMKs with H4350 or H4831SC for plates and 95 Classic Hunters with H4350 for chucks... All hammer!
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[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i1166.photobucket.com\/albums\/q609\/zandnubbz\/IMG_4911_zpskqvt5kcv.jpg"}[/IMG2]H4831SC and 107 SMK (4 shots)
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/i1166.photobucket.com\/albums\/q609\/zandnubbz\/IMG_4909_zpskqu1yufb.jpg"}[/IMG2]H4350 and 95 Classic (4 Shots)
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H4350 and 107 SMK (5 Shots)
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H4350 and 107 SMK (5 Shots)
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My LRP 07 6.5 CM has the thermal d and shoots in the .2's - .3's with factory 120 and 140 ELD's. Much like Zand's groups above. I don't know if the TD makes any difference but I couldn't ask for a better rifle. I only do strings of 5 with a few minutes rest in between so I am probably not getting big benefits from having the TD. If the zombie apocalypse comes then I'll be better covered.
Since this is back alive, I've wondered about the use of paste too? Would typical heat transfer paste survive barrel temps? What is it, boron nitride or other filler in what kind of carrier? Are they counting on the two surfaces mating so well that it isn't an issue?
Barrel temp is a big issue here in CO for 3-gun type stuff. The sun is pumping in 1000w/sq m , on a still day, with a black gun and a long stage, the gun gets hot. Black metal in the sun can get close to boiling- and keep guns warm.
I have the original VTAC type fore end, and that does hold onto heat- and it gets hot too.
It will keep your barrel cooler so Common Sense should tell you that Heat will wear out your barrel faster than anything so if you have Aluminum Fins taking heat away from your bore then it give your barrel a longer life, especially if you do a lot of Rapid Fire. I have them on all 3 of my JP Rifles and I have used a Thermometer to test the Heat and not only does it take Heat away from your barrel but it allows your barrel to COOL DOWN faster.
So if I can Capt. Obvious this, if it is a SS barrel that you put some coin into and will be shooting it hard like in 3-Gun and want to keep it accurate, then it makes sense. If you are running a CL barrel that you are using as a hose beast with mil-surp ammo- then it might not be that overall beneficial. It really doesn't address the issue we have out here in CO of hot guns on sunny days and guns melting bags, usually from the comp.
Do the fins provide the majority of cooling from airflow or radiation? I guess the increased surface area helps both.
Do the fins provide the majority of cooling from airflow or radiation? I guess the increased surface area helps both.
Decided what the hell and ordered one for my JP 308 bbl along with an Odin Works O2 Handguard which appears to have about as much ventilation as one could manage. Hope the latter is sufficiently stiff so as not to droop all over the place.
I think JP missed a few tricks on this, they should make barrels without a gas block journal shoulder, just a straight 0.750" profile back to the chamber area and make the fins from a hollow extrusion reamed for a thermal fit over that 0.750" profile and long enough to make the front a gas block journal shoulder.
If the aluminum is sized right, it will stiffen the barrel behind the gas block and might be lighter than a fluted barrel of equal stiffness. Then they could flute the front of the barrel too for a real fancy setup.
The trick will be getting the thermal fit just right so it doesn't loosen when the barrel heats up.
A handguard with better air flow and a POF style barrel nut are improvements too.
I like the POF style handguard in theory. In practice it make it difficult to set up due to the rail height and it would be much nicer if my top rail was 1-2 inches longer (mine stops at the barrel nut area, not a continuous rail).
If the aluminum is sized right, it will stiffen the barrel behind the gas block and might be lighter than a fluted barrel of equal stiffness. Then they could flute the front of the barrel too for a real fancy setup.
The trick will be getting the thermal fit just right so it doesn't loosen when the barrel heats up.
A handguard with better air flow and a POF style barrel nut are improvements too.
I like the POF style handguard in theory. In practice it make it difficult to set up due to the rail height and it would be much nicer if my top rail was 1-2 inches longer (mine stops at the barrel nut area, not a continuous rail).
Coming from a 3 gun background and now getting deep into PRS Gas Guns I'm a believer in the thermal dissipator. My practice rifle is a JP 18" 223 and match rifles are JP 6.5 Creedmoor. In practice I'll go through a couple hundred rounds working barricades, positions and drills. In the Texas summer the dissipator cools the barrel down in much less time than without it. That means less time waiting and more efficient practice for me. Every now and then we will put on a 5 stage, 50 shot per stage "Hoser" bay style match. Typical times to empty mags for rifles are between 20-30 seconds and yeah, the dissipator heated up my handguard a bit. But that heat came out of the barrel. In a PRS match, I have had 3 shooters run the same 6.5 Creed. The dissipator pulled a LOT of heat out of the barrel that day but we all smashed some targets and the barrel stayed cool enough.
So, the dissipator works and it works really well. It certainly doesn't hurt accuracy at all. If you're going to use your rifle hard, it's a necessity in my opinion. Plus they look really cool colored in gold
So, the dissipator works and it works really well. It certainly doesn't hurt accuracy at all. If you're going to use your rifle hard, it's a necessity in my opinion. Plus they look really cool colored in gold
Finally got my dissipator, barrel and handguard together. As ntoed earlier, the lack of thermal paste with the dissipator is surprising. Have some on the way and will be installing the dissipator shortly.
Also, JP barrels are bloody lovely looking.
Also, JP barrels are bloody lovely looking.
Well, in case anyone decides to try thermal paste, it's a messy operation. Used some silver based stuff that I knew from back in my PC (computer, nit plate carrier!) building days and, well, it's just not easy to work with. Thinned it a bit with 99% isopropyl alcohol and was able to mount the dissipator easily enough. Cleanup is a bitch though.
I'm actually wondering what if any effect the dissipator would have on barrel harmonics - it's pretty stiff and I would have to assume has some effect.
I'm actually wondering what if any effect the dissipator would have on barrel harmonics - it's pretty stiff and I would have to assume has some effect.
I have the thermal dissapator and notice a big difference when holding the hand guard of the upper with it versus my other ars.
I spent about an hour behind a JP Enterprises 6.5 Creedmore ar10 this past Saturday at Dead Zero shooting park in Spencer TN. This was a high end AR 10 and it had the heat dissapator. The rifle belonged to a 3-gun shooter who was at a match that day. I asked the obvious questions about the heat dissapator and was told it's only an advantage when shooting higher volume of rounds in a short period of time. He also told me that he had a Wilson Combat AR 10 6..5 with a fluted heavy barrel and it shot just as well under similar conditions. Hope this helps.
Haven’t used a JP barrel, but it just makes sense (been thinking about them for +10yrs); when PRS and benchredt shooters talk about 1st shot through 5th shot and noticing shot stringing from barrel warping from heat, and in this in relatively slow rate of fire to boot. And after 10 or 15 rounds “I had to let the barrel cool down”. So it just makes sense heat dissipation, whether with fins or extra mass in steel (bull barrel), is beneficial to barrel accuracy. And it can only make the barrel stiffer, which is a positive too.
And one of the greatest place a barrel wears is at the throat, ostensibly due to heating of steel plus bullet passage. Anyway that heat can be lowered can only be good.
I just worry about how even the dissipation is occurring. Any unevenness could cause, what warping there is, to do it in an unpredictable way. And I never heard/read there was any sort of thermal paste used, which should totally and absolutely work to alleviate that concern.
Just my 2cents.
And one of the greatest place a barrel wears is at the throat, ostensibly due to heating of steel plus bullet passage. Anyway that heat can be lowered can only be good.
I just worry about how even the dissipation is occurring. Any unevenness could cause, what warping there is, to do it in an unpredictable way. And I never heard/read there was any sort of thermal paste used, which should totally and absolutely work to alleviate that concern.
Just my 2cents.
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