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fishmasterdan · Member

You can do it..... My story
So I have never owned an air gun until a month or so ago, and thought it would be fun to play with.
After buying a springer I quickly decided I needed a PCP gun for more power and to tinker with.

After surfing around on the internet I decided to go with the 22xx platform due to all the after market parts you can get.

After about a month I have a fun working gun.

I see alot of people asking about filling stations ect so I thought I would post up what I did.

Gun
Crosman Custom 2240
I went with the longest barrel (24") and .22 caliber
Parts for gun.
Muzzle mack valve
O-Ring kit I ruined alot of O-rings Smile

.
QB tank block
13 CU 1600 psi HPA tank and regulator

Filling options
I purchased a scuba tank off craigs list for 50$
Part to fill from tank to HPA bottle scuba fill station I went to my local paint ball store for a few accessories and to get the scuba tank filled.

Other mods I did.
Drill the tube and pin it to the gas tube so it would not move when I filled it with air.
Mess around with springs for the hammer.
I cannot take the tank off because the gauge and fill portion hit the barrel.
The whole expercience has been alot of fun. Overall I am very happry.

O ya its one loud mother......

I am getting 846 av FPS with 14.3 crosman hunting pellets
and 746 avfpr with 18.1 Diablo exact pellets.
Using an F1 Chrony from Pyramydair

I tried several other type pellets but they all tumble for some reason.

I hope that help some of you that are looking for parts. I am going to keep tinkering. I will post up some picts and data hopefully later this weekend.

Please offer up any advice to improve performance.

Dan

rsterne · Moderator

I'm glad to see that you used the MuzzleMack valve extension.... big help to the safety of your project.... one question, however....

Did you do anything to secure the QB tank block beyond using the two screws provided with it?.... While it will probably stand 1600 psi OK if you ever have a regulator failure, the whole gun could become pressurized to 3000 psi (I assume that is the fill pressure on your 13 cu.in. tank).... I know of one instance where this happened and the holes where the bolts are to mount the QB block in the main tube stretched and were about to rip out of the end of the tube.... but the bolts sheared first and the tank/regulator/QB block assembly blew off the end of the gun and went spinning across the floor.... Shocked

Fortunately, nobody was injured.... moments before the tank was aimed at the owners face.... It is reported he did have to check his shorts, though.... Rolling Eyes

The QB tank block can be secured to the tube by either adding two 8-32 socket head cap screws with the heads set deep enough to be in shear.... or by a 3/16" steel shear pin through both the tube and tank block.... In either case, they would have to be installed between the two O-rings on the tank block.... which means that the rear O-ring will be doing all the work.... If properly done, this is OK and won't leak.... Wink

Bob

packrat · Senior Member

Even though I do not own a PCP, I have given this thought, more than once...Aluminum tanks don't weigh very much ie: a Luxfer 13, rated at 13.2 cu.ft. of air (it's called "cuft" ) only weighs 5.94 pounds EMPTY . Weight when full, naturally, would depend on how the 13.2 cuft of air weighs, plus what ever the regulator and other essentials add up to. Remembering my military career, I think of the back pack, and wonder if one couldn't just use a harness and carry the tank as a back-pack. Might be awkward for a time, but at least you'd have a refill(s) at the ready....just a thought-Have NO idea how much a full tank with accessories, would weigh.
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fishmasterdan · Member

I secured the QB block with the supplied screws and added one more for saftey (on the bottom).

I dont think I would try and back pack my scuba tank, that thing must weigh 25lbs or more.

rsterne · Moderator

How did you add another screw on the bottom?.... The hole running through the round part that enters the tube is very close to the bottom and you would drill into it if you tried to put another screw there.... Shocked

Bob

fishmasterdan · Member

Its a 4mm set screw.

rsterne · Moderator

Good luck and enjoy.... and pray your regulator never fails.... Wink

Bob

fishmasterdan · Member

Thanks for the advise Bob.

I am using the high shear bolts like these.
http://www.palmerbolt.com/catalog.asp?prodid=593599&showprevnext=1

I noticed today that end of the tube did not have enough meat and started to bow the tube.
So I took your advise Bob.

I milled it down flat and moved the mount hole to the center of the O rings.

fishmasterdan · Member

So I added some pictures in the main page.

I am really having fun with this!!!

So Hammer spring questions.

With the stock hammer spring I get 800 FPS with the spring bound to the hammer when its cocked. That spring is .030" thick.

I picked up some new springs to try at the local hardware store. The closest I could come up with is .040". That shoots (Max I recorded 920 fps) but there is not adjusting it down.

I am hoping to find a spring that gets me from 700 to 920 when adjusted. I am thinking .035" might do the trick. I cant find one!!!

anybody know were one can purchase that thickness of spring??

Dan

rsterne · Moderator

The hammer spring from a Discovery is 0.035" wire and the correct length.... If you can't adjust your 0.040" spring it's probably too long (ie too much preload with the adjuster backed all the way off).... Wink

Bob

packrat · Senior Member

That is an AWESOME looking piece, makes me want to abandon my idea of buying an NPSS, and have Mountain Air do me up one alomg the same lines as your as pictured. man oh man oh man !! Loks great..I bet it really is fun to play with Cool

fishmasterdan · Member

Thanks Packrat. I have a springer and a PCP now, and as far as I am concerned I will never use a spring gun again. they are not very accurate and kick your fillings out of your head.

rsterne;
I am thinking along the same lines as you. I cut it down once. Its about 1/2" shorter than the stock one. I will cut it down a little more.

I am trying to get my hands on a discovery spring.