SOLVED: bad barrel - work on it or replace it?

[palonej]

I am sure I'm not the only one that let out a very deep sigh Jason!!
Extremely well done my friend!!

[airgunwarriors]

Just one of the many reasons I cannot wait to send my .22 QB-80 Deluxe HPA back to you for the follow-up Tune-up that will make it even more awesome than it already is!

Great stuff Jason...great stuff!

AGW.
(Al)

[K.O.]

Hi  Jason I do have a question now that you have Done the full tune and tamed the barrel and learned/felt what your changes brought;

and it is will you next time just get a new barrel  or will you try to tame it first?

[nervoustrigger]

Kirby, on Saturday Amazon delivered a pair of scope mounts that Andy had shipped to me.  That was for the purpose of aligning them to the bore on each rifle using an optically-centered scope, so when Andy gets them back he can drop in his scopes and know that all he has to do is zero them.  I took care of the .22 cal over the weekend; today I worked on the .177.  It didn't take long to get it sighted dead nuts at 25 yards.  Satisfied after putting 4 in a row into the 5/16" red bullseyes of some printed targets, I then blasted 3 small Mardis Gras beads hanging from the same target board.  Reactive targets are fun!  From there, I put 3 shots onto the 43 yard target to confirm the windage was dead on.  Very close, applied two clicks then headed across the street where there's a little more room.  No targets are set up there but I wanted to just play around so I started picking out leaves roughly 1" to 1.5" in size out between 60 and 65 yards to see if I could hit them.   Took a few test shots to assess the holdover then proceeded to hit 3 or 4 out of every 5.  I'm prone to canting a rifle without a level and lightweight pellets (7.3gr) at that distance get pushed around pretty badly so I was blown away!

What have I learned?  I've learned that even the most hopeless looking barrel has the potential to be a one-holer if I try every imaginable accurizing procedure.  I do not necessarily feel like I learned something that is likely to apply to the next problem child, and chopping a barrel will continue to be one of the last things I am willing to do after exhausting most every other option.

However, I do feel like I learned to recognize a pretty gross example of harmonics.  Initially groups were so large and so seemingly random that I could not identify a pattern.  But after doing a series of cleanup steps to the barrel and deburring and polishing the pieces of the action, I began to gain some shot-to-shot consistency...enough to get some semblance of grouping which helped me see that when switching pellets and/or changing velocity, groups would migrate to different quadrants on the target.  That behavior is what pointed back to harmonics.  By that time I felt like we had nothing to lose by chopping off some of barrel, and I would have considered it a success if doing so managed to get groups to consistently fall in the 1/2" to 5/8" range at 25 yards.  But to see it now grouping in the 3/16" - 3/8" range just tickles me.