outerlimits Posted November 2, 2007 Share Posted November 2, 2007 now that i've written off ever seeing my old barrel, i was looking at a new JP ultrlight. john's site sez something about the barrels being manufactured to fit their specific uppers. so, anyone put one of his barrels on non-jp uppers? if so, any issues? Link to comment Share on other sites More sharing options...
GentlemanJim Posted November 2, 2007 Share Posted November 2, 2007 I think the interchange with all ar15 uppers...have seen them on dpms uppers Jim Link to comment Share on other sites More sharing options...
smokshwn Posted November 2, 2007 Share Posted November 2, 2007 Butch, First sorry about the shitty deal you experienced I had the same problem with a well regarded institution and it soured me. JP's barrels should go on any quality upper. Probably want to check headspace if you are using your old bolt, but other than that it should work great. The JP's are great barrels, but if you are looking to save a couple of scheckels you might either look at a Rock River Barrel or a DPMS barrel and have Benny turn it down to the profile you want??? just another option. Good luck, Craig Link to comment Share on other sites More sharing options...
outerlimits Posted November 2, 2007 Author Share Posted November 2, 2007 Butch, First sorry about the shitty deal you experienced I had the same problem with a well regarded institution and it soured me. JP's barrels should go on any quality upper. Probably want to check headspace if you are using your old bolt, but other than that it should work great. The JP's are great barrels, but if you are looking to save a couple of scheckels you might either look at a Rock River Barrel or a DPMS barrel and have Benny turn it down to the profile you want??? just another option. Good luck, Craig thanx craig- i have a dpms upper that's only about 1 yr old. i'd ask benny, but he's got a ton of work and i need a barrel real fast. Link to comment Share on other sites More sharing options...
Scout454 Posted November 3, 2007 Share Posted November 3, 2007 (edited) I've put JP barrels in Colt, DPMS, Rock River, LMT, ArmaLite and Bushmaster receivers. If the bolt is used (worn) check the headspace. ETA: ArmaLite Edited November 3, 2007 by Scout454 Link to comment Share on other sites More sharing options...
Chris Posted November 5, 2007 Share Posted November 5, 2007 Your putting an ultralight (pencil thin barrel) on your open gun? Link to comment Share on other sites More sharing options...
uscbigdawg Posted November 5, 2007 Share Posted November 5, 2007 Heck yeah! Rich Link to comment Share on other sites More sharing options...
Bear1142 Posted November 5, 2007 Share Posted November 5, 2007 (edited) I ran an ultra-light JP barrel for a couple of years and it was very accurate, but I noticed a tendency for it to wander when it heated up. The ultra-light is really that! If I remember correctly, it's .500 under the handguards. I've come to the conclusion that that's a little too thin. I remember having issues with long-range steel at several matches, so I did a test. I attempted to mimick a stage environment where you had multiple close up targets to engage, then you had to settle down and make some long-range precision shots. At the range I fired two 5-shot groups for accuracy at 200 yards with a cold bore. When done, I ran a 30 round magazine on some steel and heated up the rifle. Afterwards I tried some more 5-shot accuracy groups. Not only did my zero shift, but my groups open up by about 30%. This confirmed for me that this particular barrel setup was not going to work for me. I built a new upper with a slightly thicker barrel. I repeated the test and the new barrel contour did not have any issues. Okay disclaimer time. Before everyone warms up their flamethrowers, this was my experience. Not all may have the same issues as I. This was not an issue with the quality of JP barrels. This barrel was quite accurate and I know of many other JP barrels that are wonderfully accurate, I would not hesistate to use them. My issue seemed to be more with the contour of the barrel, not the quality of the barrel. Erik Edited November 6, 2007 by Bear1142 Link to comment Share on other sites More sharing options...
Chris Posted November 6, 2007 Share Posted November 6, 2007 That was my thinking as well. The barrel profile is too thin and if I remember correctly, John Paul (JP) does not recommend the ultra-light for heavy 3-gun use. Link to comment Share on other sites More sharing options...
outerlimits Posted November 6, 2007 Author Share Posted November 6, 2007 That was my thinking as well. The barrel profile is too thin and if I remember correctly, John Paul (JP) does not recommend the ultra-light for heavy 3-gun use. well chris, i guess i could get the med version, at a cost of what, 16 oz? yer the rifle guy, so that what u suggest? i want light, but i want accuracy... Link to comment Share on other sites More sharing options...
kurtm Posted November 6, 2007 Share Posted November 6, 2007 Well let,s see, the "Busy Bee" said it shifted, but no value of that shift, but groups grew by 30% now most J.P. barrels shoot about 3/4 MOA, some better, but most are right around there, so that would be an increase of 1.5 inches at 300 yards, so assuming a 10" target at 300 we are still WELL inside it's diameter, now if it walked 2 MOA hot it would still hit right at the edge of a plate at 300 yards with 25% of the shots missing off the side. Now unless that thang shuffled off to Buffalo he should still have had 75% of his shots hit even with this extream shift. Ain't sayin it ain't true just triing to put it in perspective and I do know he is mighty handy with a carbine, but a 2 MOA shift would be extream even for a barrel hogged down by .030 at a time chucked into a head stock and water quenched when it glowed! Now a lot of matches have been won by a 2 MOA rifle so I am wondering...or wandering...it must be the heat Disclaimer: Mr. Lund is an amigo and I to devil the heckl out of him, so take the above for what it is worth! KURTM Link to comment Share on other sites More sharing options...
Bear1142 Posted November 6, 2007 Share Posted November 6, 2007 he should still have had 75% of his shots hit Kurt, You are too good of a shooter for me to concede 25% misses at any range to you. Erik Link to comment Share on other sites More sharing options...
TRUBL Posted November 6, 2007 Share Posted November 6, 2007 JP no longer makes the .500" contour. They went to a .650" contour for the ultra light barrels. The .50 contour was, IMHO very good....very fast....very accurate. I too noticed my groups open up from .5MOA to .75MOA after the barrel heated up. Thats about 50% increase......but still at 200yards my groups held at just over 1.5" if I read the wind right. (compared to 1"). Keep in mind, that was done off of a machine rest.....5 shot groups....10 group ave. I think he still has some of the .500" contours in stock, but all new ones are .650" Once again Kurt.....you are correct!!! Percentage does'nt always tell the story. Link to comment Share on other sites More sharing options...
kurtm Posted November 6, 2007 Share Posted November 6, 2007 Yes Erik I AM good at shots! I like Tequilla and Bourbon! Link to comment Share on other sites More sharing options...
Scout454 Posted November 7, 2007 Share Posted November 7, 2007 And good single malt scotch! Link to comment Share on other sites More sharing options...
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