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Re: Crosman 1322

Posted: Sat Jan 18, 2014 11:19 am
by Brian the brain
Guessing??
Ofcourse a bigger volume needs more pumps to reach the same pressure! :lol:

It also means you should be able to go higher.
Say you need to do 3 pumps for every single pump needed before.

That last pump, before, was almost to hard to do.
You could now manage one pump, maybe two, past that ( former) limit, but not the third if you know what I mean.



What's the max amount of pumps you have tried?
Reached the limit yet?

Nice increase in velocity BTW.
Especially since the advertised 460 is probably 430 in reality..

The real gain from using a balanced valve would be the larger flow.
This should enable you to use a bigger caliber without losing performance like you would get if you'd use the stock valve.

I'm feeling a weird mix of envy and pride...that valve is my baby you know...I wish I could have had a chance to try it in a Crosman variant myself...although I'd lean towards the CO2 versions.

And no...it won't freeze up.

Re: Crosman 1322

Posted: Sat Jan 18, 2014 12:15 pm
by PeteS
jackssmirkingrevenge wrote:The package it came in says it was doing 460 fps, presumably that was at ten pumps...
Yeah, my unmodified one gets 450 fps on 10 pumps. It has since had steel receiver, nicer sights, and trigger makeover, but no changes that should improve muzzle velocity. I am pretty happy with it in this mode for it's current use which is indoor target practice and a bit of activity that I can't mention here due to forum rules.

Re: Crosman 1322

Posted: Sat Jan 18, 2014 6:45 pm
by FragmentedSanity
Results seem promising, I, like BtB, think its well suited to a big bore barrel. Probably work very well with a 24 inch barrel in .22 from crosman aswell.

The big difference I'm assuming will be how many pumps the valve will dump before retaining air, that's why the stock valve is only reccomemnded for 10 pumps, becuase it starts holding air much past that, and actually reduces performance. With this valve I'm expecting it to be able to dump a lot more air!

Probably impractical to pump 50 times each shot, but I imagine performance would be nice! Was it getting hard to pump at 25? And what was the report like compared to stock?

Keen to see further results!
I want t know what gives out first, your ability to pump further, or the valves ability to dump all the air.

Re: Crosman 1322

Posted: Sun Jan 19, 2014 6:23 am
by jackssmirkingrevenge
Brian the brain wrote:Guessing??
Of course a bigger volume needs more pumps to reach the same pressure! :lol:


Of course, of course... but maybe :D

What I mean was, while the valve should be better, it should not be expected that the same number of pumps should give more power.
What's the max amount of pumps you have tried?
Reached the limit yet?
25 so far, it really does get tedious :) in fact I'm thinking of adding a delrin tube to reduce the volume, after all we know that for the same amount of air, moar pressure and less volume means moar power.

As to the limit, let's look at how the valve compares with the original.

The area available for the pressure to keep the valve shut is 36% that of the original, so technically you can go 3 times as high before the hammer is ineffective. Also, the return spring is much weaker, to the extent that you need to cock the hammer in order to fill.

With the current setup I reckon I can go to at least 50 pumps and still have full chamber dump.
The real gain from using a balanced valve would be the larger flow.
This should enable you to use a bigger caliber without losing performance like you would get if you'd use the stock valve.
Don't forget that there is a 3.4mm hole in the barrel which I haven't touched, so it has significantly more potential...
I'm feeling a weird mix of envy and pride...that valve is my baby you know...I wish I could have had a chance to try it in a Crosman variant myself...although I'd lean towards the CO2 versions.

And no...it won't freeze up.
I believe there are a couple of young machinists in your area, I'd be happy to supply drawings ;) though converting a 2240 valve would be a challenge because of the requirement to pierce the CO2 capsule.
Results seem promising, I, like BtB, think its well suited to a big bore barrel. Probably work very well with a 24 inch barrel in .22 from crosman as well.
That would certainly take advantage of the bigger chamber.
The big difference I'm assuming will be how many pumps the valve will dump before retaining air, that's why the stock valve is only recommended for 10 pumps, because it starts holding air much past that, and actually reduces performance. With this valve I'm expecting it to be able to dump a lot more air!
Yup, see above.
Probably impractical to pump 50 times each shot, but I imagine performance would be nice! Was it getting hard to pump at 25?
Not particularly hard but too much pumping gets boring, I will probably find a way to reduce the chamber volume.
And what was the report like compared to stock?
It's pretty, pretty loud.
PeteS wrote:Yeah, my unmodified one gets 450 fps on 10 pumps. It has since had steel receiver, nicer sights, and trigger makeover, but no changes that should improve muzzle velocity.
Power isn't everything, it certainly is a design that scrubs up nicely even if you leave it performing stock :)

Re: Crosman 1322

Posted: Sun Jan 19, 2014 6:53 am
by PeteS
jackssmirkingrevenge wrote:
PeteS wrote:Yeah, my unmodified one gets 450 fps on 10 pumps. It has since had steel receiver, nicer sights, and trigger makeover, but no changes that should improve muzzle velocity.
Power isn't everything, it certainly is a design that scrubs up nicely even if you leave it performing stock :)
Yep, I really like mine in it's current form. It suits my use very well. OTOH, I am intrigued by the more modified versions.

Re: Crosman 1322

Posted: Sun Jan 19, 2014 7:44 am
by jackssmirkingrevenge
Calculated the internal volume and was quite surprised by the result, I got 2.7cc - when the original was calculated to be 0.8cc! Definitely the case for some chamber volume reduction, 30 pumps is already past what I would like in terms of effort per shot.

Re: Crosman 1322

Posted: Sun Jan 19, 2014 9:19 am
by PeteS
jackssmirkingrevenge wrote:I got 2.7cc - when the original was calculated to be 0.8cc!
Wow big difference! No wonder so many pumps.

Re: Crosman 1322

Posted: Mon Jan 20, 2014 11:23 am
by coen4d
Trigger mod, one of many:
http://www.network54.com/Forum/275684/m ... u+think---

Valve mod:
http://www.mp661k.com/sitedocs/13xx_HotRod.pdf

Maybe some interesting info for you.
There is a lot that has been done to these kind of guns.

Also you can order longer barrels from crossman, just do a search on the forum of the first link and you will find the part number.

Nice project!

Re: Crosman 1322

Posted: Mon Jan 20, 2014 12:18 pm
by sagthegreat
Is there a way you can modify the pump? maybe a longer arm for more of a wedge, and therefore less effort, or maybe increase the stroke length?

Re: Crosman 1322

Posted: Wed Jan 22, 2014 12:40 pm
by jackssmirkingrevenge
coen4d wrote:Trigger mod
Already done ;)
Valve mod
Completely redone :D
Is there a way you can modify the pump? maybe a longer arm for more of a wedge, and therefore less effort, or maybe increase the stroke length?
You would need to change the pump tube, too much bother.

Some more progress in the meantime, I slid a bit further down the slippery slope and made a brass safety button to replace the stock plastic item, and added a grub screw to the breech to stop the barrel from rotating.

A 5 shot string at 20 pumps had a velocity coefficient of variation of less than 0.01 which makes it remarkably consistent.

Herewith some final photos:
1322final01.jpg
1322final02.jpg
1322final03.jpg
1322final04.jpg

Re: Crosman 1322

Posted: Wed Jan 22, 2014 1:25 pm
by PeteS
Very nice.

Since you already slipped down the slope a bit, it sure would look nice with a walnut fore-end and grips :)

BTW, I have another 1322 on the way, a birthday present for my grown daughter. I am pretty sure she will enjoy it, as she likes to shoot. I plan to give it to her in original form except for a trigger make-over.

Re: Crosman 1322

Posted: Wed Jan 22, 2014 1:57 pm
by jackssmirkingrevenge
PeteS wrote:Since you already slipped down the slope a bit, it sure would look nice with a walnut fore-end and grips :)
It sure would, but that would be purely cosmetic and a lot of effort, I have more pressing commitments at the moment.
BTW, I have another 1322 on the way, a birthday present for my grown daughter. I am pretty sure she will enjoy it, as she likes to shoot. I plan to give it to her in original form except for a trigger make-over.
Nice - the variable power certainly makes it accessible to most shooters, I'm sure she will enjoy it :)

Re: Crosman 1322

Posted: Sat Jan 25, 2014 2:25 pm
by Brian the brain
Maximum pumps I tried was 30 and this gave an average over a 3 shot string of 563 fps, putting it at 10.1 ft-lbs, and just over one and a half times as powerful as advertised. Considering I kept the standard 10 inch barrel, I am quite happy with the results - and will stop there :)

150% the power?

Hmm.

Plan on filling up the airchamber to reduce the number of pumps?

Re: Crosman 1322

Posted: Sun Jan 26, 2014 8:59 am
by jackssmirkingrevenge
Brian the brain wrote:150% the power?

Hmm.
Would you have preferred more :)
Plan on filling up the airchamber to reduce the number of pumps?
I made an insert that removed about 1cc and got some very disappointing results, at 20 pumps it was giving me 2 shots and at 25 pumps it wasn't firing at all. It can't be that the balanced spool was compromised, because the "balance chamber' is open to the atmosphere and it would not have retained pressure. Curious.

One of the areas that can definitely use some improvement is the sealing.

Valve block, transfer tube, breech and barrel are all metal to metal fittings.

If the barrel is 11mm diameter and the breech hole is 11.1mm, then the area where air can be lost is 0.017 square cm - this is the equivalent of drilling a 1.5mm hole in the barrel, which is certainly not helping matters. Some form of liquid gasket will certainly have a considerable effect on performance.

Re: Crosman 1322

Posted: Mon Jan 27, 2014 9:13 pm
by Gippeto
One of the areas that can definitely use some improvement is the sealing.

Valve block, transfer tube, breech and barrel are all metal to metal fittings.
Machine a metal transfer port...seal the ends with small cross section metric o-rings (captured is preferred)...or poly tube mod...or machine a one piece TP from teflon. All work well depending upon the build specifics.

http://www.network54.com/Realm/CFTech/Bioportupdate.htm


Came across something the other day which may be of interest....claims are, as far as I know....still only claims.