GTA
Airguns by Make and Model => Crosman Airguns => Topic started by: 45Bravo on December 22, 2013, 11:49:24 PM
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Hi, I have been playing with my 1322, and it has been astoundingly accurate, but noticed a while back that it started wearing out the hole for the pivot pin on the pump tube.
I recently picked up a backpacker that had had some mild mods done to it, and a steel breach.
With the stock barrel, it WANTED to be accurate, but it would throw flyers.
And in watching the trajectory through the scope, sometimes it was verticle, and followed a clean arch, sometimes it would go from low left to high right, then back to low left again.
I was shooting from a rest, and careful not to cant the gun.
Also, the power out put was not what what I thought it should be..
Up on pulling the breech and barrel off, I noticed the valve was slightly turned, and the valve port was partly obscured by not being aligned with the transfer port in the steel tube ( it was off to the left by half the hole)
Also, the probe in the 2289 was not an extended probe.
I realigned the valve, and did a nylon transfer port mod.
And replaced the probe with my mellon air extended probe.
The groups with the stock barrel improved greatly, and the arching trajectory went away entirely.
And the power was back to where it should be.
I THINK (that's dangerous for me) that the air entering at a swirling entry was causing 2 issues,
1 it was crushing part of the pellet skirt because part of the pellet skirt is over the transfer port and in the path of the pressurized air. (I recovered pellets from my trap and all of them had some degree of skirt deformation)
And 2 I think the disturbed air acting on the deformed skirt made the problem worse. (Ok 1 issue, but I think 2 contributing factors)
I then replaced the barrel with my stainless walther barrel off the 1322, now it is shooting as accurate as the barrel in known to be.
Anyway, long story short, when some of the people upgrading to a steel breach wonder "why should I get an extended probe"
Look at this photo.
Steel breach, with a standard length probe seats the pellet in the wrong place.
(http://i41.tinypic.com/t64idk.jpg)
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Point taken.
Joe
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Why I don't want a extended probe ,
I do not need it.
the leade in on my 1322 is such that pellets with a tap on the butt stock seat just past the port.
for my 1377 and to make shure with my 1322 I use an L shaped piece of plastic as a seating tool...
Why do I want any more blocking the port I just hogged out?
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Not that extended probes do not work I just have to do it my way ;)
My Daisy has one but I honestly think the person that did it made it to thick and I might thin it.
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Just so I understand, cuz I'm not x-actly sure what you're talking about.
The probe is attached to the bolt. The probe goes into the pellet skirt & seats it.
The pellet is supposed to sit forward of the transfer port?
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some pellets like jsb have softer skirts and those are more effected than harder like the premiers imagine them bending just slightly creating
a small imbalance
also you want all the energy pushing forwards not pushing the pellet against the barrel wall.
so yes just past the port.
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With about half a dozen various pellets the stock probe in my new DBO leaves 50-80% of the port covered. I plan on doing the tubing port mod so I'll definitely do an extended probe too! I don't have a chrony but I do have some lumber, maybe I'll do a depth comparison.
Is there any harm to putting a notch where the bolt handle rests at the back? I tend to hold the gun pointing slightly down and the bolt slides shut all the time so I'm thinking about putting a notch there to gravity hold it at least.
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Yes the probe pushes the pellet into the barrel.
Unless like K.O. You use a pellet sweater to seat it past the port.
Some people like the no probe, some people like the hollow probe, some people like the extended probes.
Some like them smaller and longer, and others like them tapered or flared.
The possibilities are endless..
I would venture to say there is no "right" answer, it depends what you like.
My extended probe has a magnet on the rear of the shaft to hold it in the rear most position while loading..
But I doubt a notch would hurt..
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I put a little tape.
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My extended probe has a magnet on the rear of the shaft to hold it in the rear most position while loading..
But I doubt a notch would hurt..
Thanks, I haven't had it apart yet but I couldn't see a reason it would be a problem. I have a plastic breech for now so I'll just take a couple of files to it.
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" the bolt slides shut all the time"
What I've done on mine, (with steel bolt n breach)
Is to glue a small rare earth magnet to the outside
of the breach back where the bolt waits to be closed.
This holds it open for me.
PS: (black out the magnet with a black marker or even better
to use a flat black touch-up pen by Birchwood, #15102 BPPF)
$0.02
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" the bolt slides shut all the time"
What I've done on mine, (with steel bolt n breach)
Is to glue a small rare earth magnet to the outside
of the breach back where the bolt waits to be closed.
This holds it open for me.
PS: (black out the magnet with a black marker or even better
to use a flat black touch-up pen by Birchwood, #15102 BPPF)
$0.02
It works good but I do not want to collect iron...
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Stickstoff, since you need a extended bolt why not get one with the magnet and save your breech?
Cothran makes a quality bolt w/magnet (although the magnet isn't mentioned) at a very good price. In fact all his goods are quality. Plus you'll have it in a couple of days.
http://www.cothranmachine.com/ (http://www.cothranmachine.com/)
If there is any iron floating around in my gun I would just as soon the bolt collects it and keeps it out of the internals.
Same thinking that puts a magnet in a transmission pan to keep shavings from floating around.
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I feel that a flow through bolt is more advantageous to seating all types of pellets uniformly, regardless of the shape/size of the cavity in the skirt. Also, since the flow through bolt seats the pellet by the skirt, there is little chance of the pellet being seated other than perpendicular to the bore. Finally, the flow through bolt is not as long as the "extended probe" type, which can make loading your pellets much easier.
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A guy over at capof did a test with different bolts, to see which was producing higher numbers. He found that NO bolt was actually better. Not by much, mind you, but better.
I should nite that he used a CO2 pistol/carbine. I don't remember exactly, but I think it was a 2400KT.
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http://www.crosman-air-pistol-owners-forum.com/board/index.php/topic,10741.0.html (http://www.crosman-air-pistol-owners-forum.com/board/index.php/topic,10741.0.html)