1322 pump handle dropping loose after shot
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1322 pump handle dropping loose after shot
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Topic: 1322 pump handle dropping loose after shot (Read 1463 times))
Luthier Vandros
Tinkerin’, Thinkerin’, & Plinkerin'
Plinker
Posts: 239
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Real Name: Frank
1322 pump handle dropping loose after shot
«
on:
July 02, 2021, 07:40:24 PM »
Hi, all.
So, I've got an Alchemy FT & Valve set and I've contoured the valve stem just after the poppet. I've also port matched the barrel to the oversized Alchemy transfer port boss. Alchemy roller trigger also installed. Prior to assembly, I completely deburred the main tube and assembled using secret sauce where appropriate. Very smooth pumping. I need to re-crony, but I'm thinking it's around 600fps @ 20 pumps. I'm having two issues that I must investigate:
1. pump handle falling open after discharging
2. 50% of the time, the bolt encounters heavy resistance when cocking
Any advice?
TIA!
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Down by ya mom an thems
"Ruining good moments since 1975"
Roadworthy
Honorary GTA Moderator
GTA Senior Contributor
Posts: 9706
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Real Name: Thomas
Re: 1322 pump handle dropping loose after shot
«
Reply #1 on:
July 02, 2021, 08:24:43 PM »
Diana under lever rifles rely on a spring and ball to hold them after cocking. As the spring tires the lever drops open. Hector Medina suggested a neodymium (rare earth) magnet. I tried the ones from Harbor Freight. They're small but a bit wimpy for the purpose. Then I went to Home Depot. They have several varieties. They do the job. You might give that a try between the lever and the barrel. I used super glue on the barrel side. Of course Velcro is also an option but I prefer the quick release to the tearing action.
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Near the Southern Coast of Washington State
Real knowledge is knowing the extent of one's ignorance.
Luthier Vandros
Tinkerin’, Thinkerin’, & Plinkerin'
Plinker
Posts: 239
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Real Name: Frank
Re: 1322 pump handle dropping loose after shot
«
Reply #2 on:
July 02, 2021, 09:20:58 PM »
Hey. brother. How goes it?
TY for the suggestion. I was concerned something was wrong. The piston and valve are not adjustable, so I was worried there was some manufacturing variance that put these two parts out of ideal alignment.
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Down by ya mom an thems
"Ruining good moments since 1975"
WyoMan
Sharp Shooter
Posts: 839
Real Name: Gary
Re: 1322 pump handle dropping loose after shot
«
Reply #3 on:
July 02, 2021, 11:00:17 PM »
Hi Frank,
Issue #1:
1) Get an adjustable piston and set the length as follows… piston makes contact with the valve when the forearm is ½” to ¾” from closing (this is best done without the piston o-ring installed, and is measured at the widest point).
2) Pin the top of the valve:
3) Reinforce the pivot:
4)
Don’t
pump it 20 (or more) times… ever. You won’t have to after these changes.
Issue #2:
1) Are you using a heavier hammer spring?... if so try this:
https://www.gatewaytoairguns.org/GTA/index.php?topic=159203.0
2) The cocking pin may be loose inside the hammer allowing the flange of the pin to tip and bind on the cocking pin slot… get a new pin
3) The action might just need a good cleaning and dry lube
4) Try working the action like this: It should be just an easy squeeze with the thumb and forefinger:
hth…
Wyo
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Wyoming
Luthier Vandros
Tinkerin’, Thinkerin’, & Plinkerin'
Plinker
Posts: 239
yes
Real Name: Frank
Re: 1322 pump handle dropping loose after shot
«
Reply #4 on:
July 03, 2021, 01:45:26 AM »
Thank you for the extensively illustrated response. Turns out the sticky bolt issue was due to my use of the wrong lengthy bolt on the breech main tube/breech link. Corrected.
The non adj piston must be stopping just short of contact. Love that piston with that big, nasty felt wiper. Need one. Beautiful gun there.
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Down by ya mom an thems
"Ruining good moments since 1975"
happymecanic
Expert
Posts: 1274
Real Name: Francois
Re: 1322 pump handle dropping loose after shot
«
Reply #5 on:
July 03, 2021, 07:46:29 AM »
Just an idea that you may try, before replacing the piston: shim it with aluminum tape, like it's done with the Beeman P17 piston.
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Canada
Luthier Vandros
Tinkerin’, Thinkerin’, & Plinkerin'
Plinker
Posts: 239
yes
Real Name: Frank
Re: 1322 pump handle dropping loose after shot
«
Reply #6 on:
July 03, 2021, 10:50:33 AM »
I have copper tape, but not sure how to shim it, as the piston is one solid piece with only a recess for the o-ring.
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Down by ya mom an thems
"Ruining good moments since 1975"
Van
Sharp Shooter
Posts: 974
yes
Re: 1322 pump handle dropping loose after shot
«
Reply #7 on:
July 03, 2021, 01:22:48 PM »
I once fixed a head space issue with a non adjustable piston by first unscrewing the valve halves and replacing the O ring with a new one. Then when you put the two halves back together, first tighten as usual then back out a little at a time till the head space between the piston and valve is as close as you can get without leaking. You can usually back out a bit without leaking with a new uncompressed O ring in there. The pump arm stayed shut much better with more FPS too. Worked great for me.
«
Last Edit: July 03, 2021, 01:27:47 PM by Van
»
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USA, KY.
Van
Sharp Shooter
Posts: 974
yes
Re: 1322 pump handle dropping loose after shot
«
Reply #8 on:
July 03, 2021, 03:10:20 PM »
Forgot to mention I had to drill and tap a new forward screw mounting hole in the valve, which is no longer in the right spot, for the trigger group so this was not as easy as it sounds . You may not want to do that fix unless you don't mind the extra work.
«
Last Edit: July 03, 2021, 03:30:31 PM by Van
»
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USA, KY.
Spooner
Expert
Posts: 1033
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Real Name: Robert
Re: 1322 pump handle dropping loose after shot
«
Reply #9 on:
July 08, 2021, 02:23:43 PM »
this has always been the reason i have been hesitant to try one of these FT setups without an adjustable piston. David at Alchemy is really good to work with. you might contact him and see if he can help? he has it mentioned that he has an adjustable piston in the works. the Mellon air valve is 60mm long and if David's is close enough to that, i have an extra adjustable piston from Mellon that i am not using. if you think it would help solve your issue, PM me and i will send it to you.
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Ohio
Luthier Vandros
Tinkerin’, Thinkerin’, & Plinkerin'
Plinker
Posts: 239
yes
Real Name: Frank
Re: 1322 pump handle dropping loose after shot
«
Reply #10 on:
July 08, 2021, 03:49:34 PM »
Van, you are a madman!
Spooner, that offer may make sense - update soon.
Thank you all!
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Down by ya mom an thems
"Ruining good moments since 1975"
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1322 pump handle dropping loose after shot