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Thread: Rotary Bolt

  1. #1
    Join Date
    Nov 2003
    Location
    NYC
    Posts
    35

    Rotary Bolt

    Dear Mr. Kaye,
    I've always wondered why there are no paintguns in existence with a rotary bolt. I think the actual mechanics of a rotary bolt would provide a number of advantages over the standard "horizontal movement" bolts that are currently prevalent. The paintgun could be made smaller as the bolt would remain in one position, and perhaps more importantly I believe cyclic rate could be increased. I base the later presumption on the idea that it requires less energy to rotate a small cylinder, when compared to moving that cyclinder forward, stoping the cylinder, moving it backward, and stoping it again. The mechanics of the operation probabably would not be that difficult. The actual firing process would be a two stage operation: rotation followed by firing. Actuation could be accomplished by a two way valve similar to those found in autocockers. The actual bolt would probably have to be hollow, actually allowing the paintball to rest inside the bolt tube itself. Instead of the current flat face the bolt would be cut at a 45 degree angle, thus allowing paintballs to fall into the bolt when the cut face was up, and sealing into the breech when the cut bolt face was rotated downward. A dual sided detent could be utilized to secure the paintball once inside the bolt. In regards to force fed loaders, the detent would not have to be perticularly agressive as the bolt itself would prevent pressure from the other paintballs in the stack. There might be some difficulty achieving an air tight seal with this design, as the current "horizontal" bolts by thier very nature have more material with which to surround the paintball, however I felt that perhaps a delrin bolt rotating in a synthtic (silicone type material) coated breech might provide an adquate seal. The delrin bolt would provide an added advantage, lowering the bolt weight and subsequently reducing the torque necessary for the rotary stage of operation. The bolt would rotate from the rear along a hollow pin, from which the air would be released into the chamber. The pin itself would be stationary with only the bolt rotating, perhaps using a sealed bearing system similar to those found on skateboards and rollerblades. The bolts rotation could be acomplished by a air driven pistion simlar to the one found on the Tippmann A5. Anyway, I'm obviously not an engineer (Bio major)or exceptional at spelling, but I have noted such rotary bolts in some of the shotguns I use for quail. I always found the action of my Browning (rotary bolt) to be smother and faster than the Benelli (blowback) and wondered why similar concepts couldn't be apllied to paintball.

  2. #2
    Join Date
    Sep 2002
    Location
    Channahon, IL
    Posts
    1,024
    The idea has come up before, in a defunct design called the Phoenix. Unfortunately, this is the only information on it I can find: http://www.paintballparadise.com/Faq/paint_markers.htm

  3. #3
    Join Date
    Sep 2002
    Location
    Channahon, IL
    Posts
    1,024
    Tons more info here, of all places: http://www.automags.org/forums/showt...postid=1117586

  4. #4
    Join Date
    Nov 2003
    Location
    NYC
    Posts
    35
    Thank you for bringing this marker to my attention. However IMO this design has a obvious flaw. The rotary bolt fuctions perpendicular to the path of the paintball. I.e. the rotational axis is 90 degrees from the path of the paintball. The problem with this design is that the alignment of the bolt becomes crucial to the functioning of the gun. Look at the delrin bolt on this gun. If it is off buy even a small amount the bolt itself will obstruct the path of the paintball. This would require tight tolerances in both the fit of the bolt and the amount (degree) of rotation. If instead the bolt ran along the path of the paintball (i.e. look the pictires of the old marker, imaginge that white delin circle on the rear rather than the side of the marker), there would be no way for it to obstruct the paintball during firing. Furthermore if the design over or under rotated, the worst that would happen is there would be a loss in effiecency as a portion of the gas would escape because the seal between the breech would no longer be tight. If the old design over or under rotates choping is basically unaviodable.

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