new 1322 project

[Tack Driver 10]

Looks like you gents have the situation "well in hand".
In the meantime in the interest of advancing airgun technology, installed a 10" 22 cal barrel on the "Elephant" gun.
Used the lightly modified stock valve.

The gun mods are: (drum roll please)
Adjustable metal cone piston and brass barrel band.
Nipped the nose on the valve to match the cup seal.
Counterbored valve and barrel, ported to .150".
Duro 90 seal on the valve.
Light valve spring.
Steel breech and 10" Crosman barrel.

With 14.3 CPHPs and 22 cal 10" barrel
05 pumps 392 FPS 04.88 FPE
07 pumps 458 FPS 06.66 FPE
10 pumps 527 FPS 08.82 FPE (-38 FPS vs the 18" barrel)
12 pumps 567 FPS 10.21 FPE (-38 FPS vs the 18" barrel)

With 7.9 CPHPs and 17 cal 10" barrel
05 pumps 468 FPS 03.84 FPE
07 pumps 537 FPS 05.06 FPE
10 pumps 630 FPS 06.96 FPE
12 pumps 661 FPS 07.66 FPE

[Spooner]

thats very impressive for a 10" barrel Ron, but i never expect anything less in your builds. 

oh, BTW... the pleasure dots you suggested came and i have put them in all my pumpers. i havent had a cigarette in 8 years... i almost lit one up! this is a silly cheap, silly effective way to take the noise out and it was an awesome find!!! thanks for that one! 

the only thing i have well in hand is a mess, lol. it will be a miracle if any of this works? i had to multi purpose my drill press to do a few things it was never meant to do. the pins will be here today and i have the poppet ready. took two threads off the valve, shaped the valve stem, lighter spring, i angle ported the valve from about half way in down to where it squared off at the bottom. i havent put the groove in the valve stem yet. i ported the barrel to .156 and i may have just done that part right as it looks decent. i do not have high hopes at this point for the rest of it.

while doing the valve stuff i realized something and now i would like to know. the valve stem opens and releases the air when the hammer strikes it. there is some clearance between the valve stem and the hole it exits to on the hammer side. what keeps air from releasing through that clearance as it releases through the TP?

oh, and... what is the o-ring size for the o-ring between the two valve halves?

questions, questions, questions... 

[Tack Driver 10]

Glad to hear the PDs worked out for you.
The thick ones are the type I used.

The o-ring size is 012 between the valve halves, 111 for the main seal.
There's always a minor amount of air that escapes from around the VS, nature of the beast.
The MRod stems seem to use higher quality steel and fit tighter.

The Elephant gun with the HP valve would make another 38 FPS.
It has the 2100 nose cap and reduced valve volume, Delrin VS etc.
That would have put it around 565 FPS 10.13 FPE with 10 pumps.

Keep hammering away at your gun, it can get frustrating at times, been there, done that.....LOL
If you get to a sticking point I can make you a FT piston to try.
They're fairly easy to make and I believe that's where you'll get the most FPS/efficiency gain.

[Spooner]

Glad to hear the PDs worked out for you.
The thick ones are the type I used.

The o-ring size is 012 between the valve halves.
There's always a minor amount of air that escapes from around the VS, nature of the beast.

The Elephant gun with the HP valve would make another 38 FPS.
It has the 2100 nose cap and reduced valve volume, Delrin VS etc.
That would have put it at 565 FPS 10.13 FPE with 10 pumps.

for what you are already getting with a 10" barrel in .22... the stuff my dreams are made of with an 18" barrel, lol.

yeah, i ordered the PD's you linked... these things are awesome! 

thanks for the o-ring size... i better get some ordered. i dont have any of that size.

[Spooner]

here is where i am...


no awards for clean and tidy here but tried my best. i stayed with the OEM valve but did not put the groove in the stem... i am simply not clear on that one and dont want to risk creating more clearance between the valve stem and the hole it exits to the hammer from.  i only have 70 duro in cast urethane but it should still be better than the buna or viton? i am limited to the derlin piston so as much as i would like to go full metal on this one, cant find them, and this is what i have to work with.

with what i was able to do, if there is still a head space issue... i honestly can say i tried everything i could to solve it. 

time to do a final cleaning of parts, check the barrel porting to make sure i got any interior burr removed, assemble and test it on the chrony. will post results soon. 

[Spooner]

results are in...
the arm open at 10 pumps remains the same. somewhere around 70 degrees or so. piston contact with valve, 1/2" exactly. some guns just cant be solved. nothing on this gun but the trigger assembly and steel breech is the same gun it was originally. everything related to the power plant has been changed and/or modified. was it for nothing?

nope...

14.3g Crosman super points

5 pumps - 413 / 5.4  increase of 14 FPS
10 pumps - 520 / 8.6  increase of 17 FPS
15 pumps - 579 / 10.6  increase of 29 FPS
20 pumps - 611 / 11.9  increase of 37 FPS (no retained air)

before the valve mods and barrel porting...
5 pumps - 399 / 5.1 
10 pumps - 503 / 8.0 
15 pumps - 550 / 9.6 
20 pumps - 574 / 10.5

so it seems that the more pumps i go, the bigger the gain. i am not unhappy with this by any means. the pumping on this now is super easy and quiet. i did add a thin o-ring to the top of the TP just to be safe and that seemed to work out well. i got decent gains in FPS over what it was. i got thrown off a little because i forgot that the lighter spring means you have to cock before pumping, but quickly remembered before having a nervous breakdown, lol. so  i learned how to do a few new things, got comfortable with barrel porting finally, and while a bit stressful... it was fun doing. with no more than i have to work with, i think i ended up with a decent build despite the head space issue. time to scope it and get it sighted in. hopefully... it will have good accuracy too. 

Wyo, Ron, and everyone who chimed in... thank you for all the help and suggestions. it is very much appreciated. 

[moorepower]

Looks like you gents have the situation "well in hand".
In the meantime in the interest of advancing airgun technology, installed a 10" 22 cal barrel on the "Elephant" gun.
Used the lightly modified stock valve.

The gun mods are: (drum roll please)
Adjustable metal cone piston and brass barrel band.
Nipped the nose on the valve to match the cup seal.
Counterbored valve and barrel, ported to .150".
Duro 90 seal on the valve.
Light valve spring.
Steel breech and 10" Crosman barrel.

With 14.3 CPHPs and 22 cal 10" barrel
05 pumps 392 FPS 04.88 FPE
07 pumps 458 FPS 06.66 FPE
10 pumps 527 FPS 08.82 FPE (-38 FPS vs the 18" barrel)
12 pumps 567 FPS 10.21 FPE (-38 FPS vs the 18" barrel)

With 7.9 CPHPs and 17 cal 10" barrel
05 pumps 468 FPS 03.84 FPE
07 pumps 537 FPS 05.06 FPE
10 pumps 630 FPS 06.96 FPE
12 pumps 661 FPS 07.66 FPE

That's smoking!! I want to do a 14" barrel on one of mine and would be thrilled with that, with the 14" barrel! What a barn gun that would make with a red dot sight!

[Tack Driver 10]

here is where i am...


no awards for clean and tidy here but tried my best. i stayed with the OEM valve but did not put the groove in the stem... i am simply not clear on that one and dont want to risk creating more clearance between the valve stem and the hole it exits to the hammer from.  i only have 70 duro in cast urethane but it should still be better than the buna or viton? i am limited to the derlin piston so as much as i would like to go full metal on this one, cant find them, and this is what i have to work with.

with what i was able to do, if there is still a head space issue... i honestly can say i tried everything i could to solve it. 

time to do a final cleaning of parts, check the barrel porting to make sure i got any interior burr removed, assemble and test it on the chrony. will post results soon. 

Your valve job looks good.
What I see is a lot of valve volume.
Even more since you cut some threads off the valve.

I measure valve volume by how much stem travel the valve has.
Your gun has about .575", my stock valve has .385" and my HP valve has .200", about the same as a 2100 valve.
The less volume the higher pressure you'll develop at lower pumps.
The gun will be harder to pump so need to balance power with pumping effort.
The stock valve is probably the best compromise of the three.

Adjustable metal pistons are out there.
The bad news is they are pricey.
Search EBay for Crosman piston.

Here's one:
https://www.ebay.com/itm/224305229081?hash=item3439a22d19:g:m4oAAOSwUzFakaue

[Tack Driver 10]

Looks like you gents have the situation "well in hand".
In the meantime in the interest of advancing airgun technology, installed a 10" 22 cal barrel on the "Elephant" gun.
Used the lightly modified stock valve.

The gun mods are: (drum roll please)
Adjustable metal cone piston and brass barrel band.
Nipped the nose on the valve to match the cup seal.
Counterbored valve and barrel, ported to .150".
Duro 90 seal on the valve.
Light valve spring.
Steel breech and 10" Crosman barrel.

With 14.3 CPHPs and 22 cal 10" barrel
05 pumps 392 FPS 04.88 FPE
07 pumps 458 FPS 06.66 FPE
10 pumps 527 FPS 08.82 FPE (-38 FPS vs the 18" barrel)
12 pumps 567 FPS 10.21 FPE (-38 FPS vs the 18" barrel)

With 7.9 CPHPs and 17 cal 10" barrel
05 pumps 468 FPS 03.84 FPE
07 pumps 537 FPS 05.06 FPE
10 pumps 630 FPS 06.96 FPE
12 pumps 661 FPS 07.66 FPE

That's smoking!! I want to do a 14" barrel on one of mine and would be thrilled with that, with the 14" barrel! What a barn gun that would make with a red dot sight!

Decent power for sure.
A 14" barrel would get about 550 FPS in 22 cal  with that setup.
What cal would you use for your barn gun?

[Spooner]

Your valve job looks good.
What I see is a lot of valve volume.
Even more since you cut some threads off the valve.

I measure valve volume by how much stem travel the valve has.
Your gun has about .575", my stock valve has .385" and my HP valve has .200", about the same as a 2100 valve.
The less volume the higher pressure you'll develop at lower pumps.
The gun will be harder to pump so need to balance power with pumping effort.
The stock valve is probably the best compromise of the three.

Adjustable metal pistons are out there.
The bad news is they are pricey.
Search EBay for Crosman piston.

Here's one:
https://www.ebay.com/itm/224305229081?hash=item3439a22d19:g:m4oAAOSwUzFakaue

thanks Ron  . i didnt reach the 550 FPS at 10 pumps like i had hoped, but it was a definite improvement over what it had before. its not what it should be for an 18" barrel, but not bad either for a .22 caliber  . i just saw your edits in the above post and i agree. switching from a derlin piston to a metal one would benefit this gun. that FTP set in the ebay link is amazing, pricey for sure, but awesome craftsmanship put in to it. sadly, it is just too much to spend at this point. i envy you guys, lol. your understanding and ability to make your own things is almost "God like". i am grateful that you guys share that knowledge. 

[moorepower]

Looks like you gents have the situation "well in hand".
In the meantime in the interest of advancing airgun technology, installed a 10" 22 cal barrel on the "Elephant" gun.
Used the lightly modified stock valve.

The gun mods are: (drum roll please)
Adjustable metal cone piston and brass barrel band.
Nipped the nose on the valve to match the cup seal.
Counterbored valve and barrel, ported to .150".
Duro 90 seal on the valve.
Light valve spring.
Steel breech and 10" Crosman barrel.

With 14.3 CPHPs and 22 cal 10" barrel
05 pumps 392 FPS 04.88 FPE
07 pumps 458 FPS 06.66 FPE
10 pumps 527 FPS 08.82 FPE (-38 FPS vs the 18" barrel)
12 pumps 567 FPS 10.21 FPE (-38 FPS vs the 18" barrel)

With 7.9 CPHPs and 17 cal 10" barrel
05 pumps 468 FPS 03.84 FPE
07 pumps 537 FPS 05.06 FPE
10 pumps 630 FPS 06.96 FPE
12 pumps 661 FPS 07.66 FPE

That's smoking!! I want to do a 14" barrel on one of mine and would be thrilled with that, with the 14" barrel! What a barn gun that would make with a red dot sight!

Decent power for sure.
A 14" barrel would get about 550 FPS in 22 cal  with that setup.
What cal would you use for your barn gun?

.22 for sure. Less chance for going thru a roof. For the distance I will shoot, I will try to find a wadcutter that shoots the best. 20yds is a long shot in a building. Wadcutters hit like a brick and don't over penetrate.

[WyoMan]

Late to answer and it looks like you've done a very nice job, Robert, but here goes...

how many threads do i take off of the valve?

you put a groove in the valve stem shaft. about how long is that groove?

I generally leave 3 to 4 full threads so that's about half.

If you keep the turned down section of the valvestem within 5/16" of the seal...


It will be entirely within the valve port...


So the full diameter stem will have a close-fit seal to the back of the valve... and yes the MRod stems are a better fit.

Not trying to overwhelm the topic but just expanding on the mild-to-wild theme...
This 1322 with a 12" barrel uses a retained-air system and makes 12 fpe with 8 (sea-level equivalent) pumps:


It has a large volume valve, RVA for tuning, slingshot hammer, ports at .165", pinned valve (of course) and reinforced pivot:







There's more to it than that; this rabbit hole is very deep 

Wyo

[Spooner]

thanks Wyo... i guessed at how many threads to take off based on your picture. i was close  . i went with the original valve stem. it turned out pretty decent without the groove. i understand now why the groove, removing threads, shaping the valve stem... allows more room for air and higher volume. it definitely works! the more pumps i go, the FPS increases by really decent amounts. i havent tried this one at 25 or 30 pumps, afraid to, lol, but i can only guess with what it does below 20. 

that 12" gun with all the brass... BEAUTIFUL!!! 

[Spooner]

i got the pump arm angle at 10 pumps solved with Tach Driver 10's help. what ever the issue was, it was related to how the Mellon derlin piston reacted with this particular build. not sure why, but Ron sent me a custom brass adjustable piston and that solved the issue. he also sent me a hybrid 760/13xx valve to try out. i ported the barrel and used poly tube in place of the TP and got...
5 pumps - 431 FPS / 5.9 FPE
10 pumps - 571 / 10.3
15 pumps - 634 / 12.8
20 pumps - 679 / 14.6

at 6 pumps... i got 501 FPS / 8.0 FPE... perfect for my needs.

unfortunately, the project in .22 is a bust. i had hoped that this 18" Crosman barrel would have decent accuracy with a Mac1 accuracy prep, but it was pretty bad. even using H&N 14.66gr with the 5.53 head didnt help. the tolerances in this barrel are just too loose. it could hit center at 20 yards a couple here and there but overall, the shots were all over the place in about a 3" diameter range. at this point, i will keep the lower part of the gun as is, waiting for an extended probe in .177 from Mellon, and go back to my .177 14.5" LW barrel which i know is accurate.

a big thank you to Wyo and Tack Driver 10. i learned new things about how high and low valve volumes work and these are things i will use on future builds. 

Ron... it was very generous of you to send me the valve and custom brass piston. your machining skills are amazing and this brass piston is truly a beautiful work of art! i greatly appreciate you doing this and this gun will live to rock another caliber very soon. 

[Spooner]

the conversion back to the LW 14.5" barrel in .177 is done. i used the exact same lower setup and changed only the barrel and went back to the stock probe/bolt. and the results are in...

Crosman Superpoint 7.4gr pellets

5 pumps - 508FPS / 8.6
10 - 660 / 14.5
15 - 732 / 17.8
20 - 772 / 19.9

at 20 yards / 5 pumps... just under 3/4" groups on center. that's the kind of accuracy a barrel should have, and the power... much more than i expected to get. i wish i could have kept the .22 setup, but i am very happy with the results. 

[IowaAirgunner]

That's a pretty good setup

[caudie]

If that second column is FPE it would take a 15 gr pellet to get those numbers.