Regulating ROF in a BBMG with constant air flow (solution)

Building or modifying BB, Airsoft, and Pellet type of guns. Show off your custom designs, find tips and other discussion. Target practice only!
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Hurricane Air Arms
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Tue Aug 11, 2020 7:24 am

Hope you're all well,

Isolation is allowing me some time to look into doing a project and along the way I've come up with another solution to the ROF problem in BBMG's. This solution does not use any pressure, springs or bolts but rather uses the initial exit motion of the pellet/bearing from the magazine to the barrel against a rotating cam to briefly shut off access for the next ball to the barrel.

This mechanism will stop the collision of BB's in the barrel and add a reasonable spacing between them whilst also increasing the power and accuracy per shot instead of the typical shotgun effect and utter mess that comes with anything without regulation on the ROF in this category.

Traditionally in the niche community of BBMG's people have used blow forward bolts, "cloud" feed and cyclone blocks to feed their ammo to the barrel. Blowforward and blowback are wonderful but cloud and cyclone waste a significant amount of air by hoping air will fill the chamber and spit out a few BB's. There are some great examples (on here too) of ROF being regulated with higher pressure air guns, but as for medium to low pressure BBMG's people have typically just shoved a bunch of ammo into a PVC cap and hoped.

The principle for this system is fairly simple; The ball has to escape, so let's use some of that energy to move a small double-ended circular cam in an anti-clockwise direction which in turn, will also block or delay the chambering of the next ball briefly.

The cam cannot block the barrel, nor can it block the magazine as its rotation arc and location allow it to hide when the ball is passing under it, and hide again when munitions push past it to enter the barrel.

The idea in itself is fairly simple and very low attrition- it also does not waste air attempting to regular the ROF. Needless to say, it would only need to be built with a pin (for rotation) and a small piece of shaped stainless steel or even plastic no larger than half a grain of rice. The circular design ensures there are no hold-ups even at higher pressures because as long as the chamber is clear, the next round will always fall.

A large scale mock-up with some tennis balls and a large PVC pipe seemed to work better than expected - Can't wait to use the system in mine. This is free knowledge. Enjoy!

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jackssmirkingrevenge
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Wed Oct 07, 2020 4:39 pm

Image doesn't seem to be working.

Here is something along similar lines I had worked on: viewtopic.php?f=29&t=23240

Feed was not very reliable on the prototype I had made but the basic idea worked:

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