Partial Resoldering of a Benjamin Model 310 Air Rifle Barrel

An old friend of mine asked whether I could fix his Benjamin air rifle, "bought with my own money", new, when he was 12. The main complaint was that it lacked power (more on that in another post) but there was also the issue of the front section of the barrel being loose.
Being a paranoid sort of guy, I reasoned that if I tried to fix his barrel without any experience I would end up destroying the gun. So I asked around on the forums to see if anyone had a beater gun that I could practice on, with the understanding that I would probably ruin it. A kind gentleman sent me one, and I did a marginal job. The front section of the barrel was resoldered, but I ended up globbing a large amount of solder on and the finish was completely ruined. I'm not even going to post pictures of the results, it was that humiliating. It'll look ok if he polishes it up though.
Oh, ok, here are two pictures of the loaner rifle.

Here you can see that there are some large solder blobs (the gun was pretty chewed up and I think had already be resoldered partially so at least the front sight isn't my fault), and that I've had to buff the metal down to the bare brass.

After cleanup it wasn't so bad, but you can see gaps in the solder line. This is entirely down to poor preparation.
In any case, I had some data about what not to do, but still felt that I didn't have enough of a plan. I decided to peruse some gunsmithing books and read everything I could on resoldering shotgun ribs, which is an analogous problem. So I read what I could and felt much more confident. At least soldering gave Dunlap some fits: "I either spoil the bluing and get a good soldering job or am so careful about the finish I get a lousy sweat joint." (Gunsmithing by Roy Dunlap)
The last part of my puzzle had to do with getting over my fear of desoldering the rest of the gun. I bought some "Tix" solder from Brownells. It has a very low melting point of 275 deg. F so I could in theory would not need to heat the gun up too much.

Here you can see the problem.

It's separated by about 4" from the front.

I used some sandpaper to clean the join area on the tube as far back as I could go.

And lightly holding the barrel against the paper sanded the other surface.

This is my setup. A moist towel around the tube, with it clamped in a vise. If the towel starts steaming I would be getting it way too hot. A kant-twist clamp holds the barrel to the tube. That front sight is soldered to the barrel and could become desoldered easily.

I fluxed with Tix flux. Next time (Oh, how I hope there isn't a next time) I will be even more careful about fluxing. You really only want flux on the joint.

I carefully heated the barrel and tube for just a few moments with a torch and touched the solder to the join on both sides. Here you can see that it did blob up a bit but it also shows a nice shiny line along the join. I may get a non-contact thermometer if I do this again so I can better gauge the temperatures.

Remember what I said about fluxing? The areas on the tube that had flux on them ended up having solder flow...but again you can see an unbroken solder line where the barrel and tube join.

This is how I wish it all looked. That small blob just picked free.

I used a graver, riffler files and a scraper to gently scrap the excess solder. Then I polished with steel wool. The original finish is pretty tough so I didn't expose the brass (much).

The graver.

A poor picture, I'll take some others when I'm done with the rifle. The blobs are far less noticeable now though.

Grip Stippling on the Diana Model 6M

I finally got around to making the grips on my Diana 6M a bit more comfortable. I had left them large so I could fit them to my hand but I never managed to get around to it until now.

I used a pencil to mark the grips where I felt material should be removed. I would fire a few shots and see how my hand was contacting the grips, the repeat the process.

Here was where there was an almost painful rubbing.

So I attacked them with a rasp, then a file and sandpaper.

Once roughly shaped, I remounted them on the pistol and shot a little more...

Getting to here with the left grip ok but the right needing a little more material removed.

Then I decided that Derrick can't have all the stippling fun so I attacked the grips with an awl.

It's insanely tedious.

At this point I wished I started by delineating the area to be stippled, so I did with a triangular file.

Getting there...

Pretty much done. Now often the stippled areas are left oil-less but I like how it looks and they are still pretty grippy.

It looks worse the closer you get...

Then the left grip...

After oiling I again decided that some delineation was warranted.

So I attacked it with a ball bur in the Foredom.

Oiled and rubbed with steel wool.

They don't look bad.

Remounted on the pistol...

It's far more comfortable to shoot now.

Derrick's Crosman Adapter for AR Muzzlebrakes

So, I'd bought a couple AR-15 muzzle brakes with the idea of adapting them to fit various air rifles in the pile. AR muzzles are threaded 1/2"-28. I procured a thread cutting die and thought I was in the AR brake business, so to speak. My original intent was (and still is) to thread the airgun barrels and screw the brakes directly to the guns. Then, as always, I got sidetracked--this time by my ever evolving Crosman/CAR 2250 project. One slight hitch, Crosman 22XX barrels are only 7/16" diameter OD-- 1/16"smaller than the threads in the brake. A simple adapter was in order.

I found a perfect piece of aluminum rod in my metal supply box. It was 0.910" OD, already had a 1/4" hole drilled through and an external taper cut on one end.

I chucked it in the 3-jaw and used the tailstock to drill it to 7/16" to fit over the Crosman barrel. I didn't drill it completely though. Just a bit more than 1" deep. Drilling it completely through for the 7/16" barrel would have left less than 1/32" of metal to hold the brake threads. Too thin. I want the barrel to bottom in the adapter, then have about .375" of aluminum with just the .250" hole for the pellet to clear, THEN the threads for the brake. It's that critical .375" section that acts as the supporting structure for the brake.

I then faced the end and started turning down to match the 0.875" OD of the muzzle brake.

A quick test fit with a spare Crosman barrel looks like a go.

Got the OD to within a couple thousandths. No measurement taken. Used a comparison caliper on the muzzle brake and got it to match. Then, flipped the adapter around in the 3-jaw. This is the muzzle end that will get the 1/2" threads for the brake. It gets taken down to a couple thou under 0.500".

Shaving away. Going to cut the 1/2"-28 threads about 3/4" in length. When I was at size, I put a very slight taper on the end to act as a starting guide for the threading die.

One of the Taig accessories is a die holder that mounts to the tailstock. This lets you rather easily cut threads concentric to the centerline of the part in the jaws of the chuck.

Another view. Using a 1" diam. thread cutting die. Typically, round, adjustable dies are used to cut new threads while hex shaped dies are for chasing (cleaning, realigning) existing threads. The die holder is turned by hand with a short tommy bar in the side holes as the headstock is held fast by hand. Lathe power is not switched on.

I then used a small cutter to relieve the last 2 threads so the brake could seat flush. A parting tool is also good for this operation.

Flipped again. Gingerly held by the newly cut threads, I buffed the jaw marks off the adapter.

A quick trip to the drill press. Used the ruler trick to find the center of the curve and drilled though.

I'd better clean this up. Gotta love the way aluminum cuts on the lathe!

The final step. Tapping threads for the setscrew that will hold the adapter to the Crosman barrel. I used an M4 x 0.7mm tap and lots of Rapid Tap cutting oil.

Adapter goes here.

Last look. The muzzle slides inside to about the center of my thumbnail.

Slide on till the barrel bottoms. Snug down the M4 setscrew with a 2mm allen wrench.

Thread on the AR muzzle brake.

There's probably a few blogs in here...

Try as I might, I couldn't help but feel a bit like James Bond when I threaded the brake onto the gun.

Nick wondered how much clearance I had between the adapter and the sunshade. About that much, Nick. About that much. Total luck. Sharp eyed (and long-time) readers will perhaps notice the Carter barrel band.

Say hello to my little friend.