2200/13XX conversion project

[AirGunEric]

Hello Doc:

So, you have an extra-long valve in the 13xx platform now? I'm not quite understanding what putting the 2200 valve rear on the flat-topped 13xx front is doing other than increasing volume- I'm assuming it is also shortening your pump stroke? If so, did you try it both ways to see which was more effective (plain flat-top vs. expanded valve volume with shorter pump stroke)?

[Doc Sharptail]

Hi Eric:

Yes, I gained about a cubic three eighths of an inch volume wise. I am using the 2200 tube, and the pump stroke is still longer than 13-XX, even with the longer hybrid valve.

The 30 some odd year old valve I'm using is acting like the stem is going to fail. For 15 pumps, that's quite decent performance. I was not expecting anywhere near that much of a gain in velocity.

I still have some work to do on this build. I'll have to make an extended rear cap, so's I can use the original 2200 hammer spring with an RVA. (there's a 13-XX hammer spring in there now with a home made stainless non-waisted hammer, and a P-rod grip and trigger.) I'd also like to come up with a new pivot block for it. The holes for the pivot pin are further back on the tube than 13-XX.

Just headed downstairs now to get her scoperized and sighted in. More to follow...

Regards,

Doc Sharptail

[Doc Sharptail]

Got it scoped with one of my 6-24X 42mm A/O Banner's. Rings are Millet aluminum 4x4 rimfire that I picked up on closeout at Wholesale Sports. I had to shim the rear ring to get enough elevation....



Not bad for cheap pellets. That's 5 per bull for those that are keeping count 12 meters distance.



Groups much better with a little power behind the pellets. I yanked the one at left, as usual....




Speaking of power...clean pull tab rivet take out on this soda can at 675 fps. I actually saw the pellet skate across the can surface and make the second hole through the scope. Sometimes 12X can be interesting....



Getting curious as to where this build is going to top out.... will see once the new valves are here.




Recovered pull tab...



...and recovered "skater" pellet with an unfired one for comparison.

Regards,

Doc Sharptail