The B3-3 Project

Way back, somewhere around 2004 and 2005, I bought a .22 caliber Chinese B3-3 air rifle. It was purchased primarily to introduce friends to air rifles. The only modification I made to it was to sand its awful stock down and coat it with black truck bed liner. Kinda gave it a tacticool look.

After several years of neglect and moves, here’s how it came out of the gun safe:

B3-3 with truck bed liner stock
B3-3 with truck bed liner stock

The stock had a few scratches and who knows what happened to the rear sight. I checked the barrel, it looked nice and clean, so I decided to chronograph it. The shots all fell around 425 fps using 14.3 gr. Crosman Premier hollow points. Not impressive, but pretty typical of these airguns.

Since this airgun is so low power, the barrel can be cut down a bit to improve velocity slightly. The barrel was then recrowned. I also cut the underlever to match. To improve the looks and ergonomics, I made a “muzzle brake” out of a piece of 1/2″ schedule 80 PVC pipe and a cover on the underlever out of 1/2″ cpvc pipe.

Beginning modifications
Beginning modifications

The PVC parts are heated until soft with a heat gun. This also expands them, allowing them to slip over the metal parts. When cool, they shrink, making a tight fit.

The breech seal was in pretty poor condition. Upon inspection, I realized that the transfer port was way too large. So large, that a 3/16″ drill bit slid in with room to spare. To fix this, I drilled out the port to 5/16″ to make room for a new port.

I constructed the new port by taking a 5/16″-18 bolt and drilling a 1/8″ hole through the center. I then cut a piece off the bolt that fit flush on both sides of the compression chamber. Here’s everything ready for assembly:

New transfer port waiting to be installed
New transfer port waiting to be installed

I used JB Water Weld epoxy putty for the adhesive. The advantage to putty adhesives is that they don’t run, creating a mess. The last thing I needed was adhesive sticking to the walls of the compression chamber. Here’s the new transfer port installed:

Transfer port installed
Transfer port installed

I then installed the new breech seal into the end of the compression chamber. At this point, I added a new spring, polished, then lubed everything up. I added a greased washer to the piston and spring guide to serve as a bearing surface and to increase spring preload a tad.

All these modifications have brought me up to a smooth cocking and shooting 500 fps. Still no powerhouse, but a gain of 2 foot pounds of muzzle energy out of a bit of elbow grease and a couple of locally sourced parts is nothing to sneeze at. It also makes this a good option for small game hunting out to 25 yards.

One problem with cutting down the cocking lever was not having a latch to secure it in position. I looked through my parts bin, but I didn’t have any latches that would work. I did find a neodymium magnet and decided to give that a shot. Again, JB Water Weld came to the rescue. I used it to attach the magnet to the underlever grip and blend it in:

Underlever grip with magnetic latch
Underlever grip with magnetic catch

This magnetic catch works so well, I can’t believe that airgun manufacturers don’t use this. The next phase of modifications involved making the rifle look better and to mount some sights.

I sanded down the action and barrel and coated it with cheap flat black paint. A clear coat was then sprayed on. The bed liner was left on the stock and a flat white paint was added. I then shot it randomly with flat black to give it a winter camo look. That was also covered in clear coat. The result came out quite nice:

To securely mount optical sights to the airgun, I ordered a dovetail to picatinny rail. This rail attaches to the dovetail groove in the action and secures with 3 screws. On the top is another screw to lock the rail in place.

I don’t have a scope yet for this airgun, so I decided to mount a much neglected red dot sight:

BSA 5 MOA red dot mounted
BSA 5 MOA red dot mounted

Note the finish on the action. Sure doesn’t look like the cheap paint that it is! Of course, looking pretty doesn’t matter. In the end, being able to hit your target is all that matters. I brought my newly finished airgun to my 10 yard range to test it out:

My humble 10 yard range
My humble 10 yard range

I used a rolled up sweat shirt in place of a sandbag. 5 shots later, I have the satisfaction of knowing the job has been well done:

5 shot group with my tuned B3-3
5 shot group with my tuned B3-3

Shooting with a 5 MOA red dot, the groups really can’t get better than that. 5 MOA works out to .5236″ at 10 yards. This rifle really needs a scope to bring out its true potential, especially if small game is going to be hunted out to 25 yards.

In the mean time, the red dot is great for plinking. My plan is add a 4×32 AO scope. I’m hoping to have groupings as small or smaller at 25 yards with optics.

I’ve got the ballistics figured out for my 5 to 25 yard workload I plan to use the airgun for:

External ballistic calculations
External ballistic calculations

Squirrel season is coming up on May 28th! I can’t wait to put this airgun through its paces!

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Author: admin

I've enjoyed shooting and hunting with airguns since my early teen years. For over ten years, I have shared my passion for airguns on this website.

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