Fixing the design flaw of the AGD Micro CA II
AGD has always been known for producing quality products, so it came as a surprise to me when I discovered what I now consider to be an inherent design flaw of their old Micro CA II.
When AGD created the Micro CA II they designed the body to incorporate a loading/ejection port for the 12 gram, and two ports on the opposite side of the loading/ejection port to assist in ejecting the 12 gram. Unfortunately, the back edge of the rear port is positioned too close to the lever opening. The tiny section of aluminum that separates the two holes is about 1/32 of an inch at the thinnest point. Example...
The problem is that this thin section will eventually crack from the stress from ejecting a CO2 with the lever. Once this section cracks it will weaken the rest of the aluminum body and, over time, the entire body will crack in half. This may or may not happen under pressure, but if it does, then there is a potential for serious injury.
After spending quite a bit of time examining different Micro CA IIs (and I've seen/own quite a few), I'm wondering if it would be worth it to have new bodies machined in order to prevent the inevitable problems with the old bodies. Basically I'd like to know how much it would cost to do a small run of 10 or 12 bodies to the specs below (note that these measurements aren't exact, but as close as I can get without a micrometer)...
At first I was hoping to redesign the body without the 2 ports on the back side, and just widen the load/eject port just like the ACI Power Stock. Unfortunately, due to design of the lever, the back port is needed to help the 12 gram eject. Example...
Basically, all I did was decrease the size of the rear port and narrowed the hole where the lever fits into. This should hopefully add enough metal between the two holes to prevent any stress fractures. I also added 1" to the overall length of the body. The original body is 9". Most of the paintball gun stocks out there seem like they were designed for small children, and have a very short overall length. Being a large adult with really long arms, I figured adding an inch couldn't hurt.
I'm not an engineer or a metallurgist so I'm hoping for some expert advise here.
Any machinists out there want to chime in, and give me a ball park idea of what something like this would cost?
Thanks in advance,
Does the rear port have to be a square hole? Looks like a round hole would work and would add more meat to the weak point.
You could try xmt and see what he would charge. It would be neat to see a CNC cut micro ca ii with custom ano. The material shouldn't be too much. Fix that old butt plate while you are at it.
The round hole and the same size as the original 12 gram seemed to work well. It does worry me if we make the 12 gram hole longer, as it may allow the cartridge to slip out of the changer after it has been pierced. The hole was made round to try and leave a bit more material in that high stress area.
Call me anytime after 1pm EST. We can figure out the next iteration of the prototypes.
OK, I'm feeling pretty confident that this design should work.
1) Overall length needs to be 10" - by adding 1" to the back (stock) end
2) Move back-rear access port forward (toward valve) 1/16th of an inch. Keep the size of the access port exactly the same as the original AGD cut.
3) Decrease length of lever port 1/16th of an inch (towards stock)
4) Decrease width of lever port to .4375" wide
Here is my diagram showing the measurements of the original AGD Micro CA II, and then the proposed redesign of the rear access port and lever slot...
I'll call to discuss.
I will acquire the new blanks on monday. Unfortunately, to save a few bucks, I had a bunch of 9.5" blanks cut. :(
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