CCS 2400KT arrived today. Called 1-800-MOD-SQUAD

[Tack Driver 10]

Ordered a CCS 2400KT during their July sale and received it today.
Has a 14.5" LW 17 cal barrel.

Cleaned the barrel and ran it over the chrony.
 
With 7.9 CPHPs got an average 610 FPS, 6.52 FPE.
A little disappointing but has a narrow .130" barrel port and the TP was leaky.

While waiting for the gun to arrive I modded a spare valve.

Bored the throat from .220" to .250".
Drilled the TP opening to .173" and countersunk port to 1/4".
Ported the valve at the TP.
Cut the valve seat to 135 degrees.
Made a Delrin valve stem from drill blank.
Did not make any volume mods as I wanted higher shot count.

With the modded valve and an 18" Crosman barrel with a .165 port:
Got 635 FPS, 12.80 FPE with 14.3 CPHPS at 78 degrees.

With volume mods, 24" barrel, heavy hammer spring and extended probe 720 FPS, 16.5 FPE is very doable.

More mods to come.

[Unk]

  May I assume that the 18 and 24 inch barrels are in .22 cal ?  It seems many mods aren’t proportional between calibers.


But what a fun platform !

Congratulations!

[Hawkeye51]

Just finished a 2400 KT in  .177cal.  It has an 18" Crosman barrel with a 6.5 TKO.. Converted it to HPA beause of fall and winter shooting last year being difficult at best with changing temps. Used a 2600 tube and fill set from Crosman parts, same triggef set polished  & lightened up. Did the 3 bolt pattern to secure valve body. Used a disco valve, I modified with angled port and a p-rod stem. Supported by a small peice of brass hobby tubing to make it fit. (thanks Bob) Bstasley o-rings. It shoots about 20 shots in the low 900 fps range. Couldn't be happier. Good luck with yours. I'm interested in that 14"Walther barrel in. 22.  Bet that makes a fine short carbine that shoots lights out. Keep us posted.

[Tack Driver 10]

The 18" and 24" barrels are 22 cal.

HPA is the way to go and I've always wanted a P-Rod so one may be in my future.

Installed an extended probe and a heavier hammer spring.
It's a 2100 spring cut down to the same length as the stock spring.
May make a power adjuster but for now this works good.

All tests run at 78 degrees.

with Crosman 14.3 grain  CPHPS= 647 FPS, 13.29 FPE
with H&N Barracuda Hunter Extreme 18.52 grain HPs= 587 FPS, 14.17 FPE
with JSB Jumbo Beast 33.956 grain pellets= 458 FPS, 15.81 FPE

Next I'll see how many shots the gun will get from a cartridge.

[pecor]

So why did ya order a 14.5" LW 17 cal barrel

[Tack Driver 10]

Made some more progress.

Worked on the stock trigger using a reworked 1701 trigger blade.
Polished and shimmed the sear, replaced the stock pins with #30 drill blank.
Lighter spring with Teflon retainer.
Brass safety.

Made a PA and extended brass probe/bolt.
The probe diameter is .257" as opposed to the loose .250".
Cocks buttery smooth now.

The silencer keeps it stealthy.

Have a wood TH stock that will get final fitted soon.

[Tack Driver 10]

All dressed up with the LW 14" barrel in 17 cal.
Balances nicely at  the loading port.

[Rick67]

Nice stock, TD! Did you make that?

[Tack Driver 10]

Nice stock, TD! Did you make that?

I made the stock from 1/2" poplar sourced from Lowes.
It's made in 3 pieces that are glued together as you can see below.
The 1/2" is ideal as the trigger frame is also 1/2" thick.
Once it's glued up you just remove everything that doesn't look like a stock.....LOL
Lots of shaping and sanding.

I have some 1/2" black walnut and want to make a few walnut sandwiched red oak versions.

[Wahotah]

That stock is rad. Very nice work!

[K.O.]

Love your work... as always.

[Tack Driver 10]

Here's an outline of how to make the stock.

https://www.gatewaytoairguns.org/GTA/index.php?topic=146554.new#new

[pecor]

So whats it shooting now with your .177 and valve mods?

[Rick67]

Ingenious!

[Tack Driver 10]

So whats it shooting now with your .177 and valve mods?

Last week the experimental Delrin valve stem released all the CO2 after shooting several shots with the heavy hammer spring.
The Delrin is pressed on but moved forward on the shaft so I machined a groove and installed a circlip.
A bit like micro surgery but the patient is doing fine.
The clip is .015" thick so ordered some .009" jewelry/dental discs to make the groove.
Put it back in the gun along with the heavy hammer spring.

Ran it over the chrony this morning:
All tests run at 78 degrees.

1. 7.90 CPHP, 655 FPS  7.52 FPE
2. 7.90 CPHP, 651 FPS  7.43 FPE
3. 7.90 CPHP, 651 FPS  7.53 FPE

4. 9.57 H&N Barracuda Hunter Extreme, 626 FPS  8.33 FPE
5. 9.57 H&N Barracuda Hunter Extreme, 627 FPS  8.35 FPE

6. 10.65 H&N Barracuda Match, 601 FPS  8.54 FPE
7. 10.65 H&N Barracuda Match, 606 FPS  8.68 FPE

8. 8.20 RWS Superpoint, 676 FPS  8.32 FPE
9. 8.20 RWS Superpoint, 666 FPS  8.07 FPE

10. 8.44 JSB Exact, 651 FPS  7.94 FPE
11. 8.44 JSB Exact, 651 FPS  7.94 FPE
12. 8.44 JSB Exact, 652 FPS  7.96 FPE
13. 8.44 JSB Exact, 646 FPS 7.82 FPE
14. 8.44 JSB Exact, 629 FPS  (Drop off)

One thing that I noticed is with the Delrin stem the velocities are very consistent.
With the original stem they varied by 20 FPS over a 5 shot string.
Possibly due to the soft seal material or the roughly machined shaft.

Got 13 good shots before dropping off.
Will try the stock light hammer spring and look at the velocity and shot count.
17 cal with a 14" barrel shouldn't need the heavy spring and is probably wasting gas.

[Tack Driver 10]

Ran the gun over the chrony Saturday with the original hammer spring.
14.5" LW barrel in 17 cal

Notice how consistent the groups are especially shots 11-18.
I have a Delrin valve stem and a 90 duro poly bumper on the back of the valve that limits
the stem travel to .105".

All tests run at 78 degrees.

1. 7.90 CPHP, 651 FPS  7.43 FPE
2. 7.90 CPHP, 644 FPS  7.27 FPE
3. 7.90 CPHP, 646 FPS  7.32 FPE
4. 7.90 CPHP,  647 FPS  7.34 FPE  Average
5. 7.90 CPHP,  654 FPS  7.50 FPE

6.  8.3 RWS SuperDome, 638 FPS  7.50 FPE
7.  8.3 RWS SuperDome, 637 FPS  7.48 FPE
8.  8.3 RWS SuperDome, 632 FPS  7.36 FPE  Average
9.  8.3 RWS SuperDome, 630 FPS  7.31 FPE
10. 8.3 RWS SuperDome, 623 FPS  7.15 FPE

11. 9.57 H&N Barracuca Hunter Extreme, 610 FPS  7.90 FPE
12. 9.57 H&N Barracuca Hunter Extreme, 611 FPS  7.93 FPE
13. 9.57 H&N Barracuca Hunter Extreme, 613 FPS  7.98 FPE
14. 9.57 H&N Barracuca Hunter Extreme, 611 FPS  7.93 FPE  Average
15. 9.57 H&N Barracuca Hunter Extreme, 614 FPS  8.01 FPE
16. 9.57 H&N Barracuca Hunter Extreme, 614 FPS  8.01 FPE
17. 9.57 H&N Barracuca Hunter Extreme, 607 FPS  7.83 FPE
18. 9.57 H&N Barracuca Hunter Extreme, 612 FPS  7.96 FPE
19. 9.57 H&N Barracuca Hunter Extreme, 596 FPS  7.55 FPE Dropoff
20. 9.57 H&N Barracuca Hunter Extreme, 592 FPS  7.45 FPE

I prepped a CCS 22 cal 14.5" LW barrel today with a .157 barrel port
so I'll be testing it in the next few days.
I think it will come in at around 11-12 FPE depending on the pellet.
Hopefully it will also be as consistent as the 17 cal is.

[Tack Driver 10]

Made this self piercing valve top from a spare 1077 plug.
Turned it down, threaded it and cut the o-ring gland.
The plug is P/N 1077-036.......$12.00

Used a modified  Mrod valve stem.
Valve port is .166".

I'll get it in the gun over the weekend for testing.

 

[Tack Driver 10]

Put the 14.5", 22 cal CCS LW barrel on the gun earlier this week and ran a full CO2 cart.
Heavy hammer spring backed out .250" on the PA.
Barrel port .157".
Average 10.60 FPE and very consistent.

All tests run at 78 degrees.

1. 14.30 CPHP, 583 FPS  10.79 FPE
2. 14.30 CPHP, 571 FPS  10.35 FPE
3. 14.30 CPHP, 575 FPS  10.50 FPE
4. 14.30 CPHP, 570 FPS  10.31 FPE 
5. 14.30 CPHP, 568 FPS  10.24 FPE

6.  18.52 H&N Barracuda Extreme, 515 FPS  10.90 FPE
7.  18.52 H&N Barracuda Extreme, 519 FPS  11.07 FPE
8.  18.52 H&N Barracuda Extreme, 517 FPS  10.99 FPE
9.  18.52 H&N Barracuda Extreme, 510 FPS  10.69 FPE
10. 18.52 H&N Barracuda Extreme, 512 FPS  10.78 FPE
11. 18.52 H&N Barracuda Extreme, 512 FPS  10.78 FPE
12. 18.52 H&N Barracuda Extreme, 508 FPS  10.61 FPE
13. 18.52 H&N Barracuda Extreme, 506 FPS  10.53 FPE
14. 18.52 H&N Barracuda Extreme, 510 FPS  10.69 FPE
15. 18.52 H&N Barracuda Extreme, 505 FPS  10.48 FPE
16. 18.52 H&N Barracuda Extreme, 506 FPS  10.53 FPE
17. 18.52 H&N Barracuda Extreme, 508 FPS  10.61 FPE
18. 18.52 H&N Barracuda Extreme, 506 FPS  10.53 FPE
19. 18.52 H&N Barracuda Extreme, 497 FPS  10.15 FPE
20. 18.52 H&N Barracuda Extreme, 488 FPS  09.79 FPE   Dropoff

Made a wood fore grip to replace the plastic version.

[Tack Driver 10]

Installed the self piercing valve in the gun and ran some tests.

All tests run at 78 degrees.

With the 14.5" LW 22 cal barrel got a small gain of 1-2 FPE  with 8 strong shots.
12.08 FPE with 18.52 grain H&N Barracuda Hunter Extreme pellets.

This valve holds a lot more gas so I cut to the chase and
installed a 22 3/4" Crosman 22 cal barrel with a .166" port.

Still got 8 strong shots but the gun came alive.

14.3 CPHP........................................706 FPS  15.82 FPE
18.52 H&N Barracuda Hunter Extreme 653 FPS  17.53 FPE
33.96 JSB Jumbo Beast.....................505 FPS  19.23 FPE

Today I put the 18" Crosman 22 cal .165" port barrel on the gun.
Tested with 2100 hammer spring cut to same length as original spring.

14.3 CPHP  Not tested
18.52 H&N Barracuda Hunter Extreme..600 FPS  14.82 FPE
With the stock hammer spring got........593 FPS  14.46 FPE
33.96 JSB Jumbo Beast.......................479 FPS  17.30 FPE

I'll stay with the 18" barrel for now and experiment with lighter hammer and springs.
Stock, this gun wastes a lot of gas since it has to pierce the cart.
I'd like to get the shot count to around 20+ with decent power.

[cobalt327]

Coming around nicely...