Whats the life on a JP barrel?

[DocMedic]

My JP barrel is starting to show POI changes after the barrel starts to heat up. At 100yards it shifts 1.5 inches right cold, and at 200 yards it anywhere from 3-4 inches, but when the barrel heats up after a 30 round dump the rifle "shifts" back to my zero. Elevation is not effected in any matter, and I have tested this issue for the past 3 days and sure enough its repeatable. My ammo is still holding MOA at 100yards even when the barrel shifts. Could it be my barrel is starting to wear down? I probably have realistically maybe 5 to 6k through the barrel the last 3 years I've on it.

[AFH]

While I don't know enough about cold barrel/hot barrel POI shifts to comment on that part of your post, I do know of one JP barrel that had over 25,000 confirmed rounds through it that when tested was shooting a 2.75" group at 300 yards.

Andy

[J.Schmitt]

John had mentioned to me at one point that he had a barrel from a well know shooter with over 20k though it. The barrel had something like 2 inches of throat erosion and was still holding 1moa.

[Religious Shooter]

Did you buy the JP barrel and install it yourself? Or was it installed by JP? Or is it a complete JP upper/rifle?

[DocMedic]

Its a complete 20" Mid Contour JP upper, last year I replaced the FF tube with a CarbonArms Feather weight, so it was basically a plug and play install.

Edited August 2, 2012 by DocMedic

[Alaskapopo]

My JP barrel is starting to show POI changes after the barrel starts to heat up. At 100yards it shifts 1.5 inches right cold, and at 200 yards it anywhere from 3-4 inches, but when the barrel heats up after a 30 round dump the rifle "shifts" back to my zero. Elevation is not effected in any matter, and I have tested this issue for the past 3 days and sure enough its repeatable. My ammo is still holding MOA at 100yards even when the barrel shifts. Could it be my barrel is starting to wear down? I probably have realistically maybe 5 to 6k through the barrel the last 3 years I've on it.

Have you changed anything on the rifel added accessories etc. Maybe something is contacting the barrel in some way when it heats up.

Pat

[Sleepswithdogs]

Check the usual suspects; optics, the crown and brake? Brake could be fouled or warn, but my experience with a bad crown was constant, erratic shooting, no variation with barrel temp but it never hurts to review all that stuff.

Tar

Edited August 2, 2012 by Sleepswithdogs

[1chota]

two things that i have seen with JP rifles: one was where the stud for the sling swivel was contacting the heat shield and caused POI shift when the barrel heated up. The other was on a barrel installed by the owner which later started to loosen up. since you state it is a JP install, i doubt the latter. you might look to see if anything in that new forearm is making contact.

[DocMedic]

Well everything was tight on it, Took off the handguards to check the nut, checked the gas block to see if anything is loose.. everything was tight and it still walked on me. Talk about bad timing, RM3G around the corner and I had to sight in the backup rifle today.. the same rifle that puked on me hardcore at SM3G It's been since fix but being bit once by it made me not want to trust it I guess I have no choice, luckily the JP guys will be there, I'll have them look at it and see what they come up with.

[pjb45]

Kodiak Precision builds some very fine custom rifles. He will be at RM3G in a couple of days.

[apriav]

I have 15K through my 18" JP barrel and it still shoots MOA. Of all the AR's I have it is the only one that will shoot 55's and 69's same poi at 100 yards, all the others have a group shift.