Crosman 1400 Pumpmaster 0.22"

Building or modifying BB, Airsoft, and Pellet type of guns. Show off your custom designs, find tips and other discussion. Target practice only!
hectmarr
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Tue Jul 02, 2019 8:39 am

Situation "desperate" that you comment, and the expulsion of the contraption to oppress the check valve, in emergencies, comical - risky. :) Lucky you did not have your face forward ... :roll:
Try to squeeze less, to get a balance between the fact that the piston is moving freely and the ring does not leave its position, I can not think of another idea ..
I think the machining of the components is excellent, I would say that it is like you have it in your head and after working hard, you are in the world outside the head. :D
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jackssmirkingrevenge
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Sat Jul 06, 2019 12:47 pm

hectmarr wrote:I think the machining of the components is excellent, I would say that it is like you have it in your head and after working hard, you are in the world outside the head. :D
I literally could not have expressed it better myself :D

Having a bit of a rethink for this after blowing more seals than a lonely Arctic explorer, let's say we stick to the original "cup" design with a quad ring that seems to work.

It might be possible to reconfigure the cup in such a way that the outlet is much wider, while adding a balancing element to the cup itself as follows:

Image

edit: Drawing it to scale, it's a little tight...

Image

Perhaps this variation would work better:

Image
hectmarr wrote:You have to make many weapons, because this field is long and short life
hectmarr
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Sun Jul 07, 2019 1:36 pm

I see that the ideas rain to solve the same problem, I know about this since it has also happened to me, with my designs. Sometimes, the "dizziness" is a bit vertiginous; heights, in any field of knowledge, produce vertigo to some extent.
This is to try and test ideas, it is the soul of all this, because once the problematic weapon shoots more or less as you want, the weapon is saved, to be fired from time to time, this allows us to remember that the problem was "defeated", this in each shot.
It seems a good solution, this variation that you drew, I say from my almost total inexperience in this type of designs, but it seems to me that the blessed - curse o'ring, is not going to bother. I follow your progress in this post that is a duet. regards :)
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jackssmirkingrevenge
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Tue Nov 28, 2023 12:37 pm

This 1400 has languished in my parts bin for some years now, I'm wondering if it could be a candidate for a much more radical project.

Here is roughly the concept I have in mind:

Image

The "blow open" idea and trigger are preserved, but the chamber and valve are moved in line with the barrel, and instead of a bolt the pellet is loaded via a sliding breech.

This geometry should make it much more efficient, much less dead volume and with a balanced spool, the transfer port can match the caliber for greater flow without undue pressure on the trigger. Hopefully therefore I would be able to up the caliber to say 0.30" and still have useful velocity.
hectmarr wrote:You have to make many weapons, because this field is long and short life
hectmarr
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Tue Nov 28, 2023 5:24 pm

It looks good and I think it's an interesting adaptation. I'm not sure how a sliding breech works...
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jackssmirkingrevenge
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Wed Nov 29, 2023 1:48 pm

hectmarr wrote:
Tue Nov 28, 2023 5:24 pm
It looks good and I think it's an interesting adaptation. I'm not sure how a sliding breech works...
Think of it like the Huben K1 whose magazine feed functions on a similar principle:

Image

The projectile is placed inline with the valve and the barrel for minimum loss and maximum efficiency

This is in contrast to the "traditional" configuration with precharged guns where the gas needs to fill up considerable dead volume and reverse direction, which yields significantly lower efficiency and reduces power potential.
giffard.jpg
hectmarr wrote:You have to make many weapons, because this field is long and short life
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