RAZZ Posted March 26, 2015 Share Posted March 26, 2015 (edited) So I'm looking for a new 3gun barrel and the jp Supermatch is one of my final contenders. One thing I've noticed when looking at accurate or match grade barrels is a similarity in barrel profiles--typically a heavy or at least medium profile from the chamber to the gas block and something around gas block size from the block to the muzzle. Now the jp seems to have a great track record in our sport, yet the barrel profile seems counter-intuitive, with a .650 diameter from chamber to gas block. With the area most susceptible to heat build up so thin (compared to most other 'match' barrels), how do the jp barrels achieve their stellar accuracy without groups opening up due to heating up rapidly (which is, so I've been told, is the reason people go with a heavy profile barrel)? ETA: My other choice is a full-on ridiculous spr profile krieger fluted barrel. Another edit: Holy crap I must be getting old. After posting this topic I did a search for 'supermatch' and found that I started a thread asking the exact same question back in 2011. Sucks getting old. Edited March 26, 2015 by RAZZ Link to comment Share on other sites More sharing options...
outerlimits Posted March 26, 2015 Share Posted March 26, 2015 Building one now-they are awesome. Link to comment Share on other sites More sharing options...
TonytheTiger Posted March 26, 2015 Share Posted March 26, 2015 Correct me if I'm wrong but you barrel looks like a mid weight outerlimits. The lighter profile under the HG is designed to be used with JP's aluminum thermal dissipator. Theoretically it's increased surface area combined with the thermal properties of aluminum should make it very efficient at cooling your barrel, without the weight of a heavy profile. Link to comment Share on other sites More sharing options...
outerlimits Posted March 26, 2015 Share Posted March 26, 2015 Correct me if I'm wrong but you barrel looks like a mid weight outerlimits. The lighter profile under the HG is designed to be used with JP's aluminum thermal dissipator. Theoretically it's increased surface area combined with the thermal properties of aluminum should make it very efficient at cooling your barrel, without the weight of a heavy profile. Nope-16" light contour. .650 under the handguard. Link to comment Share on other sites More sharing options...
TonytheTiger Posted March 26, 2015 Share Posted March 26, 2015 I stand corrected. Looks deceiving without the HG I guess. Link to comment Share on other sites More sharing options...
gose Posted March 26, 2015 Share Posted March 26, 2015 Correct me if I'm wrong but you barrel looks like a mid weight outerlimits. The lighter profile under the HG is designed to be used with JP's aluminum thermal dissipator. Theoretically it's increased surface area combined with the thermal properties of aluminum should make it very efficient at cooling your barrel, without the weight of a heavy profile. Nope-16" light contour. .650 under the handguard. Arent all JP barrels .650 before the gas block and the only difference is the contour after? Link to comment Share on other sites More sharing options...
michael1778 Posted March 26, 2015 Share Posted March 26, 2015 Correct me if I'm wrong but you barrel looks like a mid weight outerlimits. The lighter profile under the HG is designed to be used with JP's aluminum thermal dissipator. Theoretically it's increased surface area combined with the thermal properties of aluminum should make it very efficient at cooling your barrel, without the weight of a heavy profile. Nope-16" light contour. .650 under the handguard. Arent all JP barrels .650 before the gas block and the only difference is the contour after? No. My first check of their web site was to the 22" medium contour 6.5 Grendel. Same shape, but different dimensions. .75 under the hand guard then .875 from the gas block to the end. I didn't look at any of the larger caliber barrels for the LRP-07. Link to comment Share on other sites More sharing options...
gose Posted March 26, 2015 Share Posted March 26, 2015 Correct me if I'm wrong but you barrel looks like a mid weight outerlimits. The lighter profile under the HG is designed to be used with JP's aluminum thermal dissipator. Theoretically it's increased surface area combined with the thermal properties of aluminum should make it very efficient at cooling your barrel, without the weight of a heavy profile. Nope-16" light contour. .650 under the handguard. Arent all JP barrels .650 before the gas block and the only difference is the contour after? No. My first check of their web site was to the 22" medium contour 6.5 Grendel. Same shape, but different dimensions. .75 under the hand guard then .875 from the gas block to the end. I didn't look at any of the larger caliber barrels for the LRP-07. I meant all their .223 barrels, which I assumed was what the OP asked about. Link to comment Share on other sites More sharing options...
michael1778 Posted March 26, 2015 Share Posted March 26, 2015 I wasn't willing to make such an assumption. But yes, in 223 and their separately listed 5.56mm NATO barrels, JP has a narrower 0.650" section under the handguard. Even the two contour options for the 18" 6.5 Grendel barrels have that same general shape that you described. :-) Link to comment Share on other sites More sharing options...
RAZZ Posted March 26, 2015 Author Share Posted March 26, 2015 I'm sorry--yes, I was looking at 223 barrels. I guess the idea of a heat sink taking the place of the heavier profile of the other barrels makes sense. You are effectively increasing the barrels ability to dissipate heat rapidly (which if I understand correctly, rapid heating is one of the causes of erosion and accuracy loss) just like a heavy barreled rifle, but you are doing it with a much lighter weight material, i.e. the aluminum of the heat sink. Link to comment Share on other sites More sharing options...
Headworked Posted March 27, 2015 Share Posted March 27, 2015 So I got to checking, as I have an early 2005 ultralight 18" barrel... It's .550 dia under the barrel, and .750 at gas block on out... Was really hoping they would bring this profile back....still holds good accuracy after 8,000 rounds Link to comment Share on other sites More sharing options...
RAZZ Posted March 27, 2015 Author Share Posted March 27, 2015 So I got to checking, as I have an early 2005 ultralight 18" barrel... It's .550 dia under the barrel, and .750 at gas block on out... Was really hoping they would bring this profile back....still holds good accuracy after 8,000 rounds Wow! That's a really light profile--it just seems to go against what I thought was necessary for an accurate 3-gun barrel. How well does it maintain accuracy after say burning through 20 or 30 rounds--like what you'd see in a stage? Link to comment Share on other sites More sharing options...
outerlimits Posted March 27, 2015 Share Posted March 27, 2015 c'mon, guys...you are talking about steel, and in the case of JP, the best. i would be more concerned with carbon fibre, but the guys shooting them say they hold accuracy just fine. Link to comment Share on other sites More sharing options...
scarabrick Posted March 27, 2015 Share Posted March 27, 2015 (edited) i shoot a 18" supermatch moa with crap wolf ammo.(shooting paper during practice only.Non match ) sub moa with bvac ammo Never tryed match grade ammo when I get the above Edited March 27, 2015 by scarabrick Link to comment Share on other sites More sharing options...
Headworked Posted March 27, 2015 Share Posted March 27, 2015 So I got to checking, as I have an early 2005 ultralight 18" barrel... It's .550 dia under the barrel, and .750 at gas block on out... Was really hoping they would bring this profile back....still holds good accuracy after 8,000 rounds Wow! That's a really light profile--it just seems to go against what I thought was necessary for an accurate 3-gun barrel. How well does it maintain accuracy after say burning through 20 or 30 rounds--like what you'd see in a stage? Razz, It does exceptionally well, when I run it properly... I never did use the heat sink, and sometimes wish that I had used it some, as the skinny portion of barrel has an ever so slight very light tan discoloration, from those fast, high round count bay stages... the heatsink would have dissipated some of that... Link to comment Share on other sites More sharing options...
ziebart Posted March 27, 2015 Share Posted March 27, 2015 Doesn't matter the brand I've never had a semi auto barrel group sub MOA repeated for me, but my JP ultralight has done very well in matches. I don't worry about how hot it gets, and it still shoots straight. Even when I hang a 308 silencer on it there is only 1 moa drift straight down. I think it has something to do with how they treat the barrel or just the quality of machinist. Link to comment Share on other sites More sharing options...
jon49erfan Posted March 27, 2015 Share Posted March 27, 2015 c'mon, guys...you are talking about steel, and in the case of JP, the best. i would be more concerned with carbon fibre, but the guys shooting them say they hold accuracy just fine.why are you concerned with carbon fiber? Link to comment Share on other sites More sharing options...
pjb45 Posted March 28, 2015 Share Posted March 28, 2015 I have a 18 medium and 16 light. If you are shooting short courses the light is very nice. The 18 is fine on short courses and long courses. I have not shot my 16 light on a longer course because the scope on the gun is only a 4x. But are crazy accurate. I never regretted having either barrel. Link to comment Share on other sites More sharing options...
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