Crosman Crosman 1322 getting 12 FPE @ 15 pumps.

Jump to latest Follow Reply
1

1000fps

Member
Jan 29, 2019
61
19
Md
Mods - 14 inch barrel - flat top valve+ piston - drilled out transfer port and barrel - added a 1 inch piece of insulated 14 gauge wire inside the air valve.

Results : 15.89 Gr hades diablo pellets...15 pumps - 570 FPS= 11.47 FPE . All the air is released in 1 shot , so its possible I could go up to 20 pumps and get 14 FPE, but I do not like to pump more than 15x.

Im curious if anyone is achieving better power/ FPE than this, at 15 pumps or less using a 14 inch or shorter barrel. I know I could go with longer than 14 inch barrel, and get more power , but im happy with 14 inch barrel length.
 
  • Like
Reactions: Treefrog and Long_Gun_Dallas
I'd recommend, if it makes sense to you, to find some of the 11mm rail barrel clamps and mount a sight to those. That is the easiest way to get the best accuracy without getting a better barrel band and steel breech.

I'm getting 585fps with 14.3gr crosman pellets @10 pumps in mine. And around 15fpe at 15 pumps. Much past that, i am not getting a full valve dump i think because the pressure inside of it is so high. Normally I am just pu.ping 10x. 14.6" LW barrel. These barrels tend to have tight chokes that do rob some power. My older 14.6 barrel was so tight in the choke I was having to use a pellet sizer to size down pellets a bit. The one I have now seems somewhat better at least to where I don't need to size pellets for it.

I think my valve is neither opened up nor filled with anything. Its been a while since i was inside it. The plenum is close to factory size. The outlet and throat has been ported, transfer port, barrel, hollow probe. Mountain air custom dual seal flat piston, and the valve body inlet is almost entirely filled with a steel pin. This raises compression pretty significantly. Really requires a better pump arm, and vigilance for proper lubrication (mac1 secret sauce) as to not wear out the pump pins, holes, or tube hole. This is my third tube, and i think 3rd pump linkage before i staryed using better lube. No noticeable wear since new lube change. I've got a Tom west forearm that is extended over the trigger guard, and has modified angle that adds leverage. Believe it or not, makes pumping so, so much easier.

received_144088458652449.jpeg
 
Last edited:
  • Like
Reactions: Grunt1776
Upvote 0
I think using a 14 inch barrel, 10 FPE @ 10 pumps is about the best we can expect. 15 fpe @ 15 pumps is also probably the best we can expect. I only have about $130 or less in my 1322..total cost including the pistol itself. ...so it is 1 heck of a bargain for something so simple, so accurate with decent power after a few mods.

Im not sure if putting a piece of thicker wire in my air valve, would result in me getting near 10 FPE..with only 6-8 pumps....that would be nice to be able to achieve that.
 
Upvote 0
JimBentley said:
What is you guys life span in these hot rodded 13XX guns?
My experience has shown excessive wear on the pump system and the valve being pushed rearward causing elongation of the retaining screw and damage to the valve body.
Click to expand...
As stated in my post, I've seen little to no wear on the tube/pump arm, pins or holes. With proper lube. Valve being pushed back does happen. But I believe it stopped at a certain point. My piston is adjustable. It is always set to barely kiss the valve body on compression stroke. It is delrin after all, so had a little give. If I felt valve push back was an issue I could pin it, but have not.
 
Upvote 0
Long_Gun_Dallas said:
As stated in my post, I've seen little to no wear on the tube/pump arm, pins or holes. With proper lube. Valve being pushed back does happen. But I believe it stopped at a certain point. My piston is adjustable. It is always set to barely kiss the valve body on compression stroke. It is delrin after all, so had a little give. If I felt valve push back was an issue I could pin it, but have not.
Click to expand...
How many shots have you taken at this state of tune?
 
Upvote 0
JimBentley said:
How many shots have you taken at this state of tune?
Click to expand...
Probably roughly a thousand. I have 8 other airguns, so if it was my only one, there's a good chance it'd get beat to death no matter what I did. I think one of the roughest things for them is shooting them rapidly. Silly thing to say or assume you could shoot them rapidly. But pumping them hard repeatedly, rapidly, back to back shooting cannot be good for them in any state. This is another reason I only tend to go to 10 pumps. And also intentionally take my time pumping/shooting.
 
Upvote 0
I just read the mods again you've done. Why are you adding a spring to the valve and expecting more power? You need that valve to open faster and dump all the air at once. Even though it is dumping the air at 15 pumps, it'll do it quicker and more efficiently in terms of power if you Lighten or get rid of the spring in the valve.

Unless you're going for a retained air setup to get 2 power shots per pump session, I don't see the need for even having a valve spring.
 
Upvote 0
muddydogz said:
I always thought Tim would have done well with a billet lever for these like he makes for the steroided benji's.
Click to expand...
The problem with the hot rodded 1322/1377 is the pivot pin holes in the tube. They need to be stiffened somehow. Those solid billet front barrel bands are almost a must for getting up into the 30 pump area.

I gave up on this platform after realizing its hard to pump a gun that much and then take an accurate shot after getting your heart rate all jacked up.
 
  • Like
Reactions: SteveV and JimBentley
Upvote 0
muddydogz said:
Dr. I hear you on the pivot holes. I've mild hotrodded three 1377s. Flat tops trigger work open the valve ports and such but i still don't pump much over 8 times. like you said, seems like a lot of work for not much in return.
I would like to turn one into a .22 though. That may be on my things to do list.
Click to expand...
Most I've hit was 811 fps with 14.3 grain at 32 pumps and had just a fart of air left over. 30 pumps was full dump and a consistent 790-800 fps.

The pump linkage is too short for all that high pressure pumping. Now setting them up for a double shot is cool too. Pump 20 times and have the valve setup for 2 mid power shots. Takes some work and alot of tear down and testing to get that set up right.
 
  • Like
Reactions: muddydogz and Hold_Over
Upvote 0
I’ve spent way too much time and effort trying to get my great friends 13XX guns to be hot rods. They are great for what they were designed to be, adding stress to one is a walk of rapidly dimensionally returns. An after market tube, pump lever, valve retaining system would fix the issues . But why on a $50 gun???
They are cheap to experiment with, but life span is short when pushed to the limits.
 
  • Like
Reactions: beerthief
Upvote 0
JimBentley said:
I’ve spent way too much time and effort trying to get my great friends 13XX guns to be hot rods. They are great for what they were designed to be, adding stress to one is a walk of rapidly dimensionally returns. An after market tube, pump lever, valve retaining system would fix the issues . But why on a $50 gun???
They are cheap to experiment with, but life span is short when pushed to the limits.
Click to expand...
That's why I went pcp and never looked back. Mods actually give you big gains usually. They're also more robust and don't just wear out.

The 13xx has the allure and potential to be a survival gun for getting food. I think alot of people believe them to be a good bugout option over a big bulky springer or a pcp that needs an air source. Let's be real though, if SHTF, I'm not grabbing my air guns lol.

Crossbow can get bigger game, small game, and 2 legged predators as well. Can also cobble up some bolts in the wild that would work for short range if need be.

All that wouldn't be an issue until the 1000s of rounds of powder ammo ran out or I get tired of carrying it all and toss it lol.
 
  • Like
Reactions: beerthief
Upvote 0
You must log in or register to reply here.
Top Bottom
Back
Home
Forums
Resources
Menu