Saturday, May 21, 2011

Attempting to copy Anthony Rienecker's Pro-Top Part 1

A couple months ago, I saw an ad in the Yellow Airgun classifieds for a "Pro-Top"--a modification to the front half of a Crosman 22XX valve that does away with the standard piercing needle. The Pro-Top was conceptualized by Anthony Rienecker as a way to get rid of the piercing needle on the valve stem thereby improving CO2 gas flow. I found his design to be fascinating in it's straightforward solution. Some of his original design ideas can be found here. Crosman's valve design jams the needle into the CO2 cartridge when the stem is hit by the striker. The needle can--and does--restrict the gas flow by plugging the hole in the cartridge momentarily. Anthony's idea was to change the front half of the valve and use the old-style 38T type piercing design. This design gets rid of the piercing needle that compromises gas flow. The same 38T valve parts are still used today in Crosman's 357. It's ingenious. If you've read this blog for any length of time, it's obvious that I'm not a power hound when it comes to airguns--but I am a sucker for a nice design. I was going to buy one, but since I had most of the parts on hand and I'm an inveterate hack, I really wanted to make one for myself even more. Make no mistake, it wasn't about the cost of a Pro-Top. At $26 shipped, they're an absolute steal. I wanted to try to make one and see what Anthony went through to make his design work. I contacted Anthony about two weeks ago via email to get his thoughts about this blog post. I ended up calling him a day later and we spent an easy hour talking about his design and it's origins. Surprisingly, he's a regular reader of this tawdry blog and encouraged me to give it a shot. I can tell you unequivocally that I wish he lived next door. He's a genuinely good guy. If you want to buy a Pro-Top, simply contact him at and he'll take care of the details.

Here we go--Hey, remember, this copy is not going to be an exact duplication of Anthony's work. I'm making a one-off based on his idea and design. His is the real deal that has gone through prototypes, testing and improvements.

Here's the spare 2240--yes, another gun from the Findlay, OH airgun show. Also scrounged up an extra 22XX valve and some brass rod

End seal on the stock valve. This one is pretty trashed. Got it used and the previous owner really overtightened the cap.

There's that piercing needle. Pressing the stem against the bench simulates the striker hitting the stem. That needle can restrict gas flow--especially when using a heavier hammer spring in an attempt to gain velocity.

Here's what I've been referring to as the 38T style piercing pieces. I have a slightly different threaded collar than what Rienecker uses.

Unscrewed the stock valve. Just trying to conceptualize how I'm going to proceed.

Cut off a 1.5" long piece of brass. Faced the ends and turned the end down.

Threaded 9/16-18 to fit the Crosman body.

Couldn't cut the full thread in the small lathe, so I transferred the work to the vise and chucked the die into a handle.


With a parting tool, I cut a groove for the valve body o-ring

Test fit.

Chamfered the end of the thread.

For concentricity, I threaded the piece into the (gutted) Crosman valve body and snugged it down. Took a very light skim cut to remove any runout between the halves.

Looked too long, so I used the parting tool again.

Spotted the front of the valve with a center drill.

Selected a #30 bit for the through hole.

After through drilling, I started an 11/32" hole then progressively enlarged it...

Until I finished the hole to 0.500" with a tiny boring bar. The 38T piercing pin and seal sit in the bottom this counterbore.

Had to make a quick run to Kromhard Twist Drill for an oddball 9/16-28 bottoming tap. The tap ran me $18.50 or so out the door at the good guy price. Vaughn at Kromhard is still waiting for the day when I just need a "normal" 1/4-20 plug tap. Don't hold your breath, Vaughn.

Only tapped the front half of the hole for the retaining collar.

More to come...


Anonymous said...


I enjoy reading about all the modifications you are doing. However, instead of what you are doing in this project I suggest another method of totally getting rid of the piercing pin in the valve and install a non-sealing piercing pin at the end cap instead. Of course, the cartridge would then have to be installed round end first. I think it could be a better set up since it would increase the volume the gaseous CO2 could occupy before each shot.
What do you think?

Rod (San Diego, Ca)


derrick38 said...

That's another project altogether since the tube itself isn't designed to be gas tight. You'd have to make a different valve front with a sealing o-ring and get it forward of the front grip frame screw. And have room for the larger end of the CO2 cartridge. I don't think that'll fit in the front end of a 2240 gas tube.

Increasing volume in the tube doesn't necessarily translate to increased performance through the valve as the amount of time the valve is open is related to the striker weight and spring tension of both the valve stem as well as the striker spring.

A Crosman 160 with over two times the gas volume isn't any faster than a Crosman 2260.

Your idea though is more readily done perhaps with a 2250 or 2260 tube where there's more room.

Anonymous said...

A few years ago, a guy on the Crosman forum did something similar...Only his valve half was longer so it would fit into a 2250 tube, using a standard 2240 end cap...This extra length in the valve body created a larger chamber for the CO2 immediately in front of the valve seat...I had one of these powereing a DAQ .25 top-end and it was very impressive...

Anonymous said...

Here is more information on the valve extension for the 2250 tube and 2240 end cap: