Morris tubes & POA/POI.

[BFMIN]

Has anyone "tuned" a tubed .22 shooter by adjusting sub-caliber tension?
I'm curious because I have an SMLE with a sub caliber .22RF "trainer barrel" conversion kit. I recently re-crowned it because under bore-scope inspection it was really rough. When reinstalled it shot better groups than before, but Way higher!
I've seen this in some revolvers like the DW where you can almost walk it onto target by "tweaking" the barrel nut to "tune" the barrel harmonics.
Might I have detuned it by changing the tension?

 

[Doco Overboard]

I think maybe as a first measure,
Pull the projie off a live round with the thickest rim of the lot of ammo you have.
If you have empties form the same that would even be a better choice or just snap the rim on the live pulled round to render it inert.
Loosen the tube, close the bolt on a de-capped case.
Then, tighten the tube at the muzzle to where it gains firm tension without over doing it and to where the tube centers itself.
Try it and shoot for group, not zero. If its not suitable, loosen the tube after making the rifle safe and using the same method re- tighten the tube only this time attempt to tighten the tube in a different position, say at six o'clock to the same tension but allowing the muzzle to center itself naturally.
If that doesn't work, pull the tube and cover with heavy grease reinserting the tube and then use the first method and so on until you remedy the regulation.
The problem origin could be vibration originating from the center of the liner or even where the chamber insert meets the liner.
Also I think with all that grease, dry the end of the muzzle and its components where they fasten together to rule out any unwarranted movement and vibration there.
Make your adjustments with the barrel cool so that with heat generated by a lot of firing any effects of expansion and cooling can be noted-accounted for.

 

[BFMIN]

Good point on the fired case, I have a bunch of them!
Grouping is fine! Its just the amount of movement when both optically & laser sighting show its about 1/2" over LOS at 25yds
I'll try that next time I get to the range.
I kept the sight settings for both .303 & .22RF in my notes, so Nothing lost, just a puzzle to work on.

 

[Doco Overboard]

What Ill do is bring my rifle and we can have a look at both of them at the same time.
Because the one I have still has the issue sights, maybe we can make a determination for mechanical zero on that one, apply the laser fire a few to determine drop and what we learn could help get things sorted.
I want to turnover some of this Wolff branded ammo to you so you can have a go with that and see what you think of it.
I bought to much of it and just dont feature it very much, but it would be interesting to do a comparison with it using a more elaborate sighting system.

 

[BFMIN]

Sounds like a nice project.
I'm guessing I over torqued the nut when reassembling & have messed up the harmonics. I'm planning on bringing a suitable wrench to re-tune it there. I have tweaked other barrels using a similar bolted in tube barrel for POA/POI this way before!
If that's it I'll witness mark the nut & nosecap in some way so I can just go back to it should the barrel ever be removed again.

 

[Clovis]

Guess I found part one...but your pics still seem a little fuzzy.

 

[BFMIN]

Something odd happened fer shure.
I posted 4 images & saw them post. Then 3 of them disappeared!
I re posted them again.