Started working on my B50 today

[Jaymo]

She developed an issue with not wanting to cock, and with some apparent valve lock. So I tore her down yesterday and started working on her in earnest today.
The cocking issue looks to be an issue of the sear contacting the stock. No problem, will be an easy 30 second fix with the electric die grinder or drill and a rotary file to remove about 1/8" of wood inside the stock, just fore of the trigger guard.

Polished the bolt, relieved the probe some, polished the spring ends, spring guide/hammer weight, and hammer.

Polished the cocking pin.

Faced off about 2 millimeters from the front of the hammer, to give it a little more travel. Thanks to spysir for that idea, as well as all the other ideas.

Next I will take a 1/4" diameter hardwood dowel, turn a taper on one end to match the breech end of the barrel, and use it, with some polishing compound to polish the bolt ways and barrel breech. Also will deburr/polish the slots where the cocking pin runs in the breech.

I may even bore out the rear of the breech and install a 1/4" ID Oilite bronze bearing. Will decide after polishing/checking sliding friction.

Need to make a valve tool to remove the valve and deburr/polish the inside of the tube where the hammer slides.

Thinking about ordering a BigEd valve stem, per spysir.

Am making a prototype ambidextrous cocking handle. Thinking about making a left handed breech. Don't have a dovetail cutter, so I may install a picatinny rail on it. Or I may set up my metal shaper to cut the dovetail grooves.

Would really like to make/install a front sight to mount on the barrel or barrel band. Can either install a rear site on barrel, or put a picatinny rail mounted site on rail on breech, if I go that route.

Gotta check my brass rod stock tomorrow and see if I have the right diameter to make some transfer ports. Thought about turning some up from delrin rod, but all I have is some 1.75" diameter that I got from my good buddy DaveShoot. I REALLY don't want to have to take about  1.375" off of that rod. That's a lot of passes on the lathe. Yeah, Delrin is easy to machine, but come on. That would take forever.
Think I'll use quadraseal O-rings on the trans port, just like I put on the bolt probe.

May part off  the bolt probe and make a longer, smaller diameter one.

Was going to go with a stronger hammer spring, but I don't think it would be a good idea. That spring is very strong, and has little enough travel, as it is.

Will probably recrown the barrel.

REALLY want to make a riser breech and shroud band so I can use a BigEd shroud.


After that, I think I'll tear into my 909 big bore. I don't have the money to have Leroy Roduner tune it, as I had originally planned.

One of these days, I'll make a real spring compressor and get to work on tuning my R9 and G1 extreme.

Man, I love vacation/holiday time.

[kp4att]

FEW PICTURES WILL BE NICE!!! /// GERALD

[geewhiz380]

u could go to the mall and look at best airgun its a pcp and the first one that china had i personally like the ones mike has cause he has them tuned already ..

[Jaymo]

Unfortunately I haven't taken any pictures yet. I polished the bolt raceway, barrel breech, and crown today, as well as deburring the cocking slot in the main tube.
Now I need to clean it all up and start putting it back together. I started turning down some brass stock for transfer ports. My brass round bar is only 1/4" diameter. it needs to be .308" diameter. So I turned down some 1/2" brass hex stock. That's a pretty decent bit of metal to take down, relative to it's original diameter, but not too bad.
Now I have to decide what diameters to make.

[Jaymo]

Did some valve work last night as well as taking a hair more off the nose of the hammer. Had to shorten the striker screw, as I had forgotten to do so before and it was causing my hammer to move slowly, thus causing problems firing with 3,000 psi. DUH!
I drilled my transfer port, as well as the exhaust hole in the valve, and air inlet port in the barrel, to .125"/3.1 mm.
I bored the inside of the valve to the major diameter of the internal valve threads, and bored out the inner 1/2 of the threads, since the valve head only screws into 4 or 5 threads, anyway.
So, I've gained a little internal volume, and flow.
I'm thinking about making a new hammer without the striker screw, and with a little shorter/thicker body, so I can groove it and install teflon rings front and back, instead of having metal riding on metal.
Teflon rings can be bought as teflon backing rings at any hydraulic shop. They're used as backing rings for packing seals and o-rings in hydraulic cylinders. At last, 15 years as a forklift mechanic may just pay off.
While I'm at it, I may install weaker valve and hammer springs, and lighten the hammer, with the goal in mind of getting 40 fpe without battering the valve stem like the B50 can do in stock form.
I was out in my shop running the lathe from about midnight last night to about 3:30 this morning. I just love having some obsessive/compulsive tendencies.

Also stripped down my Benji HB20 pumper pistol that I bought off the classifieds here. Gonna clean everything and polish the tube and hammer. Then I'll moly coat the hammer(maybe) and do some valve work. The goal here is to greatly reduce pumping effort and improve power some, if possible.


The goal with the B50 is to get the maximum power possible while maintaining good hunting accuracy. Not looking for 100 good FT shots per fill. More like 25 full power hunting shots per fill.
Next, I'll need to get a breech riser and barrel shroud. Thinking about making a left handed riser breech for it, myself. I just don't have any ball nosed endmills, much less one big enough to radius the bottom of the breech.
I may have to see if I can set it up in the Atlas shaper to do that operation.