DIANA CHASER .22 pellet loading resistance

[nervoustrigger]

That's just a macro photo taken with my antiquated digital camera.  From that angle we can only see about 3/16" of the rifling so it's not enough to detect any spiral.

As for not being able to perceive a step on your barrel, it's definitely there solely on the basis that you can see a smooth section where the rifling was reamed out.  Therefore the bore has to be a smaller diameter, leaving some sort of transition point between them.  Whether it's tall enough or sharp enough to cause the harsh chambering remains to be seen.

[nervoustrigger]

Mike, yeah it's interesting you brought that up.  Back when I was just beginning to read about bore polishing, the accepted wisdom seemed to be that if you're using a cleaning rod to do it, it's critical that it be a ball bearing type so the patch / wad / cleaning pellet will follow the rifling spiral.  Intuitively it wasn't obvious to me that it is so critical.  Certainly it makes sense if going all out and pouring a lead lap but not so much for a compressible lap.  For the very reason you stated, it seemed to me that breaking the sharp edges of the lands would have no detrimental effect on their ability to impart spin to the pellet while simultaneously making it less apt to strip lead off.  I questioned it here on the forum but got neither corrected nor backed up.

It wasn't until a few weeks ago that I saw Ernest's tutorial where he spun the barrel in a lathe while moving an abrasive cloth up and down the bore.  There was my answer.

Granted there's going to be some softening of the edges when using the first method, and it may also have a benefit of smoothing the inside corners where the base of the rifling meets the groove.

Ultimately it seems either method will yield good results when applied properly, so my takeaway isn't that one is demonstrably better than the other.  Rather, it's that barrels aren't the fragile little flowers that we've been led to believe and sometimes they need a little tough love to make them act better.

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Good morning nervoustrigger & KnifeMaker
Here are the pellet push results

The push stick used was a .177 caliber patch holder with double patches; hand held, not on a push rod
5 different pellets tested
3 offered different but moderate resistance 
2 were NO GO (bent the  patch holder)   

As mentioned, the abrasives are on the way.
From a past unrelated project I have abrasive compound in stick form (without wax) in white, red, & black.
Would any of these be useful?
Thinking of using a .177 or .22 bore mop (no bristles) as the tool

BTW
You two are teaching me a great deal.
Thank you

Ed

[Pelletjunkie]

Focus on the rifling right where it starts after the transfer port. You want to turn that edge the guys have shown you in the pictures into a ramp. After the transfer port, you want your pellet to glide right up into the rifling as you close the bolt.

[nervoustrigger]

Ed, for softening the transition into the rifling, you need something pretty aggressive.  A bore mop, for example, is too forgiving.  The rubberized abrasive bits in a cone shape will do a good job.  My main concern with those is you can’t feel the work as you go, and you can’t see how it’s going either (unless you have a bore scope).  So it’s easy to do too little or too much.  The thing I recommend to beginners is to use a dowel or skewer with sandpaper wrapped around it, and sweep it in and out by hand.  That way you can feel how it’s doing.  When the sandpaper stops getting shredded by the sharp edge and the lip becomes harder to feel as the dowel passes over it, you know you’ve done enough. 

Here’s a current thread where I explained in more detail if you’re interested.
https://www.gatewaytoairguns.org/GTA/index.php?topic=161641

[K.O.]

here is a link to pics of my Storm .177 in post #2 there is no step but the rifling does need made into a ramp to feed the pellets skirt into the rifling... sharp edged rifling cuts the lead of the skirt leaving little fins... if the rifling is ramped it swages the skirt and makes no little fins off of the base of the skirt... some times it makes a big difference in accuracy... some times it just helps the barrel be less pellet picky...

It is called a leade... powder rifles have leades also just different... but they both lead the pellet/boolit from the chamber into the rifling..

https://www.gatewaytoairguns.org/GTA/index.php?topic=151471.0

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Ed, .  The thing I recommend to beginners is to use a dowel or skewer with sandpaper wrapped around it, and sweep it in and out by hand.  That way you can feel how it’s doing.  When the sandpaper stops getting shredded by the sharp edge and the lip becomes harder to feel as the dowel passes over it, you know you’ve done enough. 

Here’s a current thread where I explained in more detail if you’re interested.
https://www.gatewaytoairguns.org/GTA/index.php?topic=161641

Thanks Jason
I read the post.
It helped a great deal
As did the photo of the dowel & sandpaper
For a 22 cal barrel is 1/8" (3.175mm) dowel about right; or is a bamboo skewer better?
Seems to me 3/16" (4.762mm) may be cutting it too close considering the thickness of the sand paper.

Small victory, maybe!
It looks as if  I've been able to visually identify the leade.
It's right there just inside the O ring seat;and looks like a steeply sloped chamfer cut into the i.d of the barrel
If that's correct, then I was looking way too far into the barrel.

Ed

[Pelletjunkie]

The leade has no rifling. Like the chamber on a real rifle. Your problem is further down the pipe where the rifling starts.

[nervoustrigger]

For a 22 cal barrel is 1/8" (3.175mm) dowel about right; or is a bamboo skewer better?
Seems to me 3/16" (4.762mm) may be cutting it too close considering the thickness of the sand paper.

Run what ya brung

The specific diameter of the dowel isn't important except that I like to use something that's pretty sturdy.  If it's too flexible, it just takes longer to get the job done. 

What I do is sweep it in and out while applying lateral pressure at the 12 o'clock position, then 1 o'clock, then 2 o'clock and so on until the whole circumference is adequately dressed. 
I deliberately avoid building up the sandpaper so large that it is touching the full diameter all in one go.  I want it slightly undersized so I can angle it at times to run the end across the step, that way I can feel how the work is progressing. 

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Ed, for softening the transition into the rifling, you need something pretty aggressive.  A bore mop, for example, is too forgiving.  The rubberized abrasive bits in a cone shape will do a good job.  My main concern with those is you can’t feel the work as you go, and you can’t see how it’s going either (unless you have a bore scope).  So it’s easy to do too little or too much.  The thing I recommend to beginners is to use a dowel or skewer with sandpaper wrapped around it, and sweep it in and out by hand.  That way you can feel how it’s doing.  When the sandpaper stops getting shredded by the sharp edge and the lip becomes harder to feel as the dowel passes over it, you know you’ve done enough. 

Jason, that rifling in the last pic looks much like the old BSA style. Convex rather than shape rectangles. When I polish a bore, I use crocus cloth to try to achieve something similar. By removing the sharp edges. This is in addition to the gradual slope into the rifling.

The leade has no rifling. Like the chamber on a real rifle. Your problem is further down the pipe where the rifling starts.

Thanks Jason
Thanks Mike
Thanks Frank
The Chaser is back together and all of those difficult pellets now load easily
It took awhile to get the hang of the procedure; primarily because I started with 400 grit instead of the recommended 320.
Once the 320 was in use I could clearly see the sharp edge at the leade as the abrasive dust etched it in the beam of my flashlight.
I finished the job polishing with 600.
Ran a dry patch to dust things off and put it back together.
Accuracy is still fine, : the new barrel & breech O rings have helped as well.
The only part of this I did not like was aligning the barrel.
The divot the center set screw sits in is not very precise; so I had to visually make sure the front sight was centered in, & square with, the rear sight notch.
Not a big deal; but something more precise would be better.
Maybe that's one of the trade-offs with inexpensive pistols.

No fear to do this again!!
What's next?

Ed

[Pelletjunkie]

You have successfully completed stage one of fixing a Chinagun. Stage 2, the crown.

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You have successfully completed stage one of fixing a Chinagun. Stage 2, the crown.

The crown!!
Same procedure?
Smoothing things, out or more specific?

What do I look for in both well machined & poorly done crowns?

[Nvreloader]

Edward

Check out the info here,   
https://www.gatewaytoairguns.org/GTA/index.php?topic=130555

Tia,
Don

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Edward

Check out the info here,   
https://www.gatewaytoairguns.org/GTA/index.php?topic=130555

Tia,
Don

Thanks for the link,Don
Great info there.
Not surprising considering that it is written by  nervoustrigger Jason`
Ed