I like shiny things.......



Author Topic: I like shiny things.......  (Read 638 times))

Offline Tack Driver 10

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  • Real Name: Ron
Re: I like shiny things.......
« Reply #20 on: February 15, 2019, 06:07:47 PM »
Ron, I am so impressed by your work!  I think you're having almost all the fun!

Sometimes I feel guilty, being a "fun hog", but hey, somebody's got to do it.....LOL

In the meantime I did the final prep on the pump tube and assembled it.
Ran some quick tests and then cobbled this temp version together from various parts.

It has a Disco breech and an 18" Crosman 22 cal barrel.
I like the Disco breech since it has contiguous scope rails and the rear 4-48 breech screw.
The piston and valve have duro 70A poly O-rings for now.
Used a 2100 plastic pump arm but there's room for up to a 12 1/2" version vs the 11" stock arm.

Should be able to run some performance tests this weekend.
« Last Edit: February 15, 2019, 06:10:23 PM by Tack Driver 10 »
  • Oklahoma

Offline Tack Driver 10

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  • Real Name: Ron
Re: I like shiny things.......
« Reply #21 on: February 16, 2019, 03:21:39 PM »
Ran the gun over the chrony.

With 18" barrel and 14.3 CPHPs:

05 pumps  496 FPS  07.81 FPE
07 pumps  571 FPS  10.35 FPE
10 pumps  657 FPS  13.70 FPE
12 pumps  709 FPS  15.96 FPE
15 pumps  761 FPS  18.39 FPE
20 pumps  819 FPS  21.29 FPE

Initially used a 2400 hammer spring and the gun retained air with 12-15 pumps.
With 15 pumps got 693 FPS with a second shot at 481 FPS.
With 20 pumps there's probably two 700 FPS shots in the gun.
Switched to a 2100 hammer spring and it dumped 20 pumps.

Good starting point.
With a longer barrel and duro 90 O-rings, +30 FPS is a good WAG.

This gun is scary consistent with my 1322 SHO, be afraid, be very afraid....LOL
It got 821 FPS, 21.4 FPE with 27 pumps vs 819 FPS, 21.29 FPE with 20 pumps for this gun.
The 1322 SHO has a 3.5" stroke. 27 pumps x 3.5=94.5" of stroke.
This gun has a 4.75" stroke x 20 pumps=95" of stroke.
https://www.gatewaytoairguns.org/GTA/index.php?topic=153687.msg155696302#msg155696302
« Last Edit: February 16, 2019, 03:47:08 PM by Tack Driver 10 »
  • Oklahoma

Offline bustachip

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  • Real Name: Thomas
Re: I like shiny things.......
« Reply #22 on: February 17, 2019, 01:37:42 PM »
Quote
This gun is scary consistent with my 1322 SHO, be afraid, be very afraid....LOL
It got 821 FPS, 21.4 FPE with 27 pumps vs 819 FPS, 21.29 FPE with 20 pumps for this gun.
The 1322 SHO has a 3.5" stroke. 27 pumps x 3.5=94.5" of stroke.
This gun has a 4.75" stroke x 20 pumps=95" of stroke.

Them ain't yer grandpappies pumpers...lol.

You do some awesome work Mr. Driver, carry on...

TMurray
  • N.C.

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