Excitement

[Gippeto]

Simplest version I've seen...took some digging, but heeeeerre it is.....


http://www.network54.com/Forum/79537...t%3B)+adjuster.

[Doc Sharptail]

Would that appeal to anyone?

I'd be interested in the delrin units for sure. As for the RVA, the tube I have here is a bit thicker walled than a stock factory tube~ in fact, a stock factory tube cap won't fit it. I don't have a lathe here- nothing to turn down a cap enough to fit. I have a brass tube cap from scopesandammo that fits perfectly...

Regards,

Doc Sharptail

[Doc Sharptail]

AHA! It's most likely the hammer binding inside the tube. Just occurred to me now, thinking about tight fitting end caps... I had to do some serious de-burring on the back of the hammer, just to get it to fit inside the tube...

Regards,

Doc Sharptail

[rsterne]

My RVA for QB's used an offset screw.... It requires the rear cocking pin to be removed so the gun is "cock-on-open"....



The setscrew on the right presses on a delrin rod that sits against the side of the RVA threads, preventing it from turning without using a screwdriver.... I ground the head of the screw to a "pear" shape so that it has an indicator point for counting full turns....

Bob

[Doc Sharptail]

I spent a great deal of time on the hammer tonight. I took a diamond cloth to it, by hand, and got it cleaned up to where it will move freely in the tube.



It's an investment casting, and a pretty poor one at that. It is very porous, and badly burred from where the cast was broken away. By the look of it, the hardening process was near the end of it's useful cycle- warm water. The rust in the spring pocket probably didn't help matters much. That dent in the rear portion looks like a tong mark to me, but there's none on the other side.

The roll-over sear binds too. I was too played out to deal with it tonight. There's a long week-end upon us, and I'll probably get time to work on it tomorrow night. I'm not in the least bit phased by this. I'm hooked badly by this new experience.

Regards,

Doc Sharptail

[Doc Sharptail]

Coming into the home stretch, now.
I'm getting 10-shot strings. Got to thinking a slightly heavier pellet would help the gun to settle in. Used up some of my dwindling supply of the 18.1 gr JSB Exact Heavy. I really gotta find another source for these, or an equivalent. I like their accuracy.

JSB Heavy Exact @ 1800 PSI

1.) 728.7
2.) 727.9
3.) 720.5
4.) 729.7
5.) 714.3
6.) 716.6
7.) 703.6
8.) 698.2
9.) 698.8
10.) 688.6

The gun almost wants to level off. I think I need to shoot the heck out of this gun. So close now!

@ 1900 PSI, same pellet:
1.) 748.4
2.) 753.3
3.) 596.0
4.) 746.0
5.) 737.1
6.) 733.1
7.) 734.7
8.) 723.3
9.) 720.4
10.) 712.1

@ 2000 PSI, same pellet:

1.) 749.9
2.) 739.3
3.) 751.5
4.) 730.6
5.) 744.7
6.) 743.3
7.) 737.5
8.) 730.8
9.) 724.1
10.) 718.5

This is getting better. An extreme variation of 30-35 fps is something to crow about! I'll be able to quit posting strings soon.

A few thoughts:

I badly want to do this again, in .177, with throttled back flow. The .22 is nice, but a little on the loud side for indoor use. I'm still gonna shoot the heck out of it- outdoors.

High pressure does strange things to O-rings. I need to get more O-rings for the fill yoke. They can only be installed, used , and removed once. They come out badly dried and compressed.

The gun is a lot easier to pump with a reserve of 1.2-1.3 K PSI in it. Am I going to be o.k. storing the gun this way? It's usual storage place is cased, in my vehicle...


Regards,

Doc Sharptail

[SeanMP]

Lookin good Doc.

If this is the velocity your looking for I'd say just a tiny touch less spring and you'll have the classic smooth curve.....For the life of me I can't figure out why your only getting 10 shots though. It should be closer to 20-25....I think?

I't possible that you'll pick up the extra shots once you find the curve.

Oh yes as far as storage I store mine with 1500-1600 in it consistently. It keeps the valve formed and all the seals pushed out.

[Doc Sharptail]

I think you guys know your stuff, and are correct about fill pressure. I'm not quite to 2200 PSI yet. By the way the gun is behaving, I'd say that's the target area, or close to it.
I could get more than 10 shots from 2000 PSI. How many, I'm not sure, but the tail end of that string is going to look like over-cooked spaghetti (?) I'm stopping in order to pump less.

I have to cock the gun when filling from completely empty. No big surprise there. The factory transfer port seal, I discarded. I'm using a rubber cylinder seal that was in my a/g junk box. I have no idea where it came from, and it fits perfectly into the 0.25" shoulder I milled into the valve body for a flatter seal. Eventually, I'll get into the crushed poly-tube thing, but not today.

I think the valve stem spring is binding against that shoulder that was cut for the factory valve sleeve/piercing pin washer. I'll probably "mill" that out, once I get a supply of O-rings for the fill yoke...

Regards,

Doc Sharptail

[rsterne]

Doc, on your 2000 psi string you are missing most (if not all) of the first half of the shot string.... I wouldn't be surprised to see you get nearly 20 shots with a higher pressure fill.... You want your first shot to be about 4% below the peak, which if it doesn't go much over 753 fps (the fastest you have so far) would be ~723 fps.... The first half of the string is more efficient than the downhill side, so you could easily double your shot count by filling to 2200-2400 psi....

Bob

[Doc Sharptail]

Thanks, Bob. Hopefully, I can get out tomorrow for a shoot, somewhere. I'm beginning to understand why so many opt for the bottle, tank, and shoe-box thing.

I hope I can make it into the gravel pit. There's an awful lot of snow to be melted here, yet.

This has been a major step for me. It's way better than what I was doing before with the 13-XX's (which still hold a place in this old heart). From a hunter's view-point, I've almost arrived!

Getting very close to the old .22 short CB cap 29 gr...

Regards,

Doc Sharptail