Polish the leade on your 392 before calling it a poor shooter

[jon.k]

When I bought my second 392 it was virtually unused. I think it was rarely used because it shot far to the left, all the way to the edge of the windage adjustment on the stock sights. It came with a peep that was never mounted, and mounting it I found it shot no better with the breech mounted sight. I recrowned the barrel; I polished the leade; it still shot far to the left. Eventually I shimmed the peep sight out to the right of the breech about 1/8" with brass shim stock and longer fillister head screws to get my windage adjustment back, and now I just live with it, and it shoots like a laser. Here's 10 shots from a shooting stick at 25 yds yesterday (4 pumps per shot). I'm sure that North Country Gal could have put these 10 shots into a circle the size of a penny, the gun can shoot--I'm just mediocre.



But this post is about a different gun. I recently posted about how I added a billet lever to my first 392, and in that post I mentioned that gun is not a great shooter. I had re-crowned this one when I got it last year, to no real effect.
Here's 6 shots from this gun at 25yds, off a shooting stick (4 pumps per shot).



So the other night I polished the leade with this stick. I based my method on a post by  TimmyMac (http://www.gatewaytoairguns.org/GTA/index.php?topic=31208.0).  The stick has a slot in the end that I put two pieces of sandpaper in, about 0.75"x0.75" square, with the leading corners torn off. Here's the stick, sitting next to a recaptured JSB 15.9 grainer:



And here's what 10 shots from this gun looks like now, off the same shooting stick, 25yds, 4 pumps per shot. The horizontal group is clearly from the shooting stick; the flyer I would be more than happy to blame on the gun, but I'm pretty sure it was me not setting up my body position carefully enough after pumping. All I can say is that I'm tickled with the gun now!



I removed the bolt, pushed the sandpaper up into the leade, and twirled with my fingers for 30 seconds or so. Then I removed it, reversed the fold on the sandpaper flappers, and repeated but twirling in the other direction. To remove the bolt you need a 7/64" allen key to back out the socket head bolt that is the cocking lug; this size was not in my go-to allen key set, but I had previously bought it to replace the mixing core on a Moen shower valve.

[oldnamvet]

What grit paper was it you used? 400, 600, finer?
I assume that you removed the bolt and did it from the breech.
How many turns did you rotate the stick?  And how far did you put the stick into the breech?
Finally, how did you judge when to quit?
I'm just full of questions when I am thinking about doing that myself.

[jon.k]

What grit paper was it you used? 400, 600, finer?
I assume that you removed the bolt and did it from the breech.
How many turns did you rotate the stick?  And how far did you put the stick into the breech?
Finally, how did you judge when to quit?
I'm just full of questions when I am thinking about doing that myself.

Sorry, I edited the original post just now with some of this info.
I used 320 grit paper. In the link above Tim says he starts with 180 and finishes with 240, but I think he's referring to a steel barrel, and I assume the brass is softer.  I removed the bolt, pushed the stick/paper into the leade, and polished the un-riflled portion where the transfer port is (back of sandpaper flush with front of loading port), then I pushed another 3/8" in and polished where I could feel the bumpity-bump of the paper rubbing over the rifling. I didn't use a power tool to polish like TimmyMac recommends in the link above ; I just twirled it with my fingers about 20-30 turns. I pulled the paper out, looked to see that some brass had loaded the grit, and I decided that doing it for 30 seconds in each direction was enough. This gun must be cocked to pump it, so I loaded a pellet, replaced the bolt (without the cocking lug), and felt how smooth it was to push it into the rifling. Then I pumped once to eject the pellet (hence the bent pellet in the photo), repeated the sanding for another 10 seconds, then repeated the loading test, and called it done because it was now loading smooth enough. In other words, I guessed that it was done, and I shot the group above to test it.

[Rob112o]

Nice work Jon. Now u gave me a mission to do. Mines shooting great as is, but if it can be fine tuned a little more why not?

[jon.k]

...why not?

I've never heard of anyone finding their gun shot worse after doing this, but if you find that to be the case be sure to let us know!

[wjjones]

Can this be done as easily on a rocker Blue Streak?

[longhunter]

Can this be done as easily on a rocker Blue Streak?

Same deal for both. You just need a different tool to remove the bolt lug.

[Rob112o]

Go to the hardware store and make yourself one of these.

[Martis 1]

Think I'm gonna have to try this on my 392.  I might use my cordless drill turning slowly instead of trying to do it by hand though.
Ron.

[jon.k]

I'm interested in seeing some before/after groups from people's 392's when they do this. The posted 'after' group above was the only 10 shots I had time for that day, but in subsequent days I've realized that my 392 is actually hold sensitive on the shooting stick, and now I'm not 100% sure that the group improved from the polishing or from a hold I happened to use that day.

So here's my setup. As you see, my shooting stick is just a forked stick that supports the gun between the stock and the forearm.



If I use my left hand to stabilize the gun behind the stick - under the stock-bolt, in front of the trigger, or even grasping the vertical stick - I get loose groups. Not all as bad as the 'before' pic above, but pretty disappointing. On the other hand, if I stabilize the gun in front of the stick, by gripping the underside of the forearm and letting the weight of my arm pull the gun into the stick, I get laser-like groups as in the 'after' pic above.

I'm not entirely sure what else to say about it, or when else this sensitivity occurs.

Avator may notice that I removed the peep. I wanted to see if my problem was scope parallax or eye-relief, and I needed to push the IA base back 1/2 inch--but the peep was in the way, so off it came.

[longhunter]

Put some padding in the crotch of that stick. The vibration of the gun, on firing, is what's throwing your shots off.

[jon.k]

Thanks for the advice. I'll try it tomorrow and see how it  works.