Started my 1325XLT project wish me luck :)

[1377x]

 And to think i sold a solid steel 2100 piston. The old colman 2100/2200 had steel p iston maybe you can get lucky and find one on ebay

[Ryan]

Is there a flat rubber pump cup available. It would be nice if there is one instead of the coned cup?

[K.O.]

Hi Ed yep a solid steel piston would be nice. 

I would have bought that grip frame off you the other day but I thought Big Ern had.

by the way you have to buy it as parts and it comes out to about 24 bucks if you get all the screws and the 2 pivot pins( I got screws local and made pins).


The valves should get to Bart tomorrow for modding.

I have a 1/4 end mill coming Monday for the Transfer port seat and that is all that is left to do besides testing.

I promised it that if it hits over 600 on 15 pumps that I will buy it a steel breech, bluing pen and np shroud parts next month...

If it hits 650 by 18 pumps then the bored  out 2289 barrel band(just enough meat left to stand up?) will be replaced by summer

it looks like this one will fit a 9/16 barrel ? http://www.bnmcustom.com/product/bb1009/ (the one for shrouded barrels)

[K.O.]

Is there a flat rubber pump cup available. It would be nice if there is one instead of the coned cup?

Not that I know of...

[plinker99]

hey K.O..
    here's the first try at an adjustable piston for a 2100.
    i cut a 1377 piston in half.  the tubing is an aluminum 3/8 od threaded inside with 5/16-20.  the bolt is a 5/16 carriage bolt cut to about 1 1/2".  i cut 4 slots on each end to fit the plastic piston & epoxy to hold it in place.
    i have not tried it yet.  will report when i do.

[K.O.]

Hi Plink

I have  a poor boys lathe (drill press)  so I was thinking about getting some aluminum bar stock and attempting something like in this thread but

longer of course also an oil control oring behind the cup on the piston body.

http://www.crosman-air-pistol-owners-forum.com/board/index.php/topic,6448.0.html

[K.O.]

I think what you attempted is a good effort but I think the stuffed piston is better in that it is pretty solid once you reinforce the X section to reduce

flexing.

Once the pressures get up towards 1300-1700 psi I do not think tubing has the strength to stand up and once it starts to flex it is crumpleville...?

honestly the fact that your stuffed piston held up to 17 pumps to me seems to suggest it will do very close to what the pump cup can give pressure

wise and the cup not the piston is the limiting factor.

[BDS]

KO.. Is this a "because I can" type of project or.. Does it have a specific end use?

20 pumps ?

[K.O.]

KO.. Is this a "because I can" type of project or.. Does it have a specific end use?

20 pumps ?

Well both  a .25 pump carbine is some thing I have wanted since I was about 12  and feel that it would make a very capable 35 yard hunter if you can

get 700 or so fps. 

this is just to see how close I can get  with Crosman parts and keeping it low budget as possible... 

but also I just love to tinker...

I do think I would love to have

1377 short carbine and pump
1320 short carbine and pump
1322 short carbine and pump
1325 short carbine and pump

1377XLT long carbine and pump
1320XLT long carbine and pump
1322XLT long carbine and pump
1325XLT long carbine and pump

Just some thing about how modular the platform is.
or it just may be that I am nuts...

I honestly want to go for a sturdy dependable 7-800 fps version of a 1325XLT but  that is $.


18-20 pumps and about 1500-1800psi  is where I think that gains will become incremental...

[K.O.]

Once I started researching I realized that the long tube 1322 and 1377 had been done using the 2100/2200 tube but not  a 1325.

I realized with a .25 bore the 2100 valve was not quite enough volume and it would be hard to get enough pressure to make up for it and that was

probably why.

I do like the idea that it will be the only/first  13xx 2x00 hybrid .25  but  not unless it gets over 600 fps @15 pumps

Theoreticaly enlarging the valve from about .1 ci to .136 ci buys 650psi at 4" into the barrel instead of being at 650 psi at 3"  into the barrel and that

is with a starting psi of 1600.

And that is obviously where most of the acceleration happens and that heavy pellet can use that extra inch...

[BDS]

Your a better man than me McGee

I just go buy PCPs 

[K.O.]

Your a better man than me McGee

I just go buy PCPs 

Never have been able to think in term of better/worse just different...

Crazier  maybe

I just think of mine as inexpensive single shot on board pump PCPs...