this information may be very helpful to those buildingpneumags, electro-pneumags like my design, and also of the direct solenoid type, like the spyder electroframed ones and such.
I recently have been testing new mods on the old electro-mag. most of you around here know what I'm talking about. I noticed that certain design aspects, when not paid careful attention to, can cause pre mature bolt wear. not something you want, especially on a rather expensive lvl10.
when setting the lpr pressure of an electropneumag type, one should calculate the approximate force needed to hold the on/off up. then divide this force measurement by the area of the piston of the MPA-3. this will give you the minimum needed lpr pressure to run properly.
basically the operating pressure of the gun times the surface area of the head of the on/off pin. example: my mag runs at 470 psi , the stock on/off pin is .116 in dia. which has a surface area of .01056". so 470psi X .01056=4.96 lbs of force. now when using the MPA-3 with the spring in it, you must add 1lb of force to this. the MPA-3s piston area is .11. so 5.96 divided by .11= 54.18 psi. so you set the lpr to a MINIMUM of 54 psi. I would recommend about 60 psi.
I noticed that the set-up can work at lower lpr pressure than it should be able to. but at this lower pressure, the MPA-3 can push the sear enough to release the bolt, but not fully have the strength to fully close the flow through the on/off. this can cause the sear to push back up against the bolt lip surface prematurely and when the bolt comes back it will scrape the bolt catch and cause premature wear. this is something that can be a potential problem in pneumag and electropnuemag designs.
another thing that causes this premature bolt wear is too short of a dwell time. this is of course, is only a problem with electropneumags, and electromags in general.
the short dwell time lets the sear come up prematurely, and it once again can scrape the sear catch lip of the bolt, causing premature bolt wear.
to find out what your minimum dwell time is, I start at 30 msec, a time that is known to be enough in most cases. then reduce your recharge time until you notice that it just starves the gun. just about 3 to 5 msec too short. then reduce your dwell time, while leaving the rof the same. if this helps the recharge, and the gun does not starve, then you know that the bolt is coming back all the way before the sear comes back and you can try to lower the dwell again. use this process and set the dwell at about 5 msec more than it needs to be. alot of times it needs to be about 20 to 25msec, so I recommend setting it to 25 to 30 msec.
I hope that was informative and not too hard to follow.
I recently have been testing new mods on the old electro-mag. most of you around here know what I'm talking about. I noticed that certain design aspects, when not paid careful attention to, can cause pre mature bolt wear. not something you want, especially on a rather expensive lvl10.
when setting the lpr pressure of an electropneumag type, one should calculate the approximate force needed to hold the on/off up. then divide this force measurement by the area of the piston of the MPA-3. this will give you the minimum needed lpr pressure to run properly.
basically the operating pressure of the gun times the surface area of the head of the on/off pin. example: my mag runs at 470 psi , the stock on/off pin is .116 in dia. which has a surface area of .01056". so 470psi X .01056=4.96 lbs of force. now when using the MPA-3 with the spring in it, you must add 1lb of force to this. the MPA-3s piston area is .11. so 5.96 divided by .11= 54.18 psi. so you set the lpr to a MINIMUM of 54 psi. I would recommend about 60 psi.
I noticed that the set-up can work at lower lpr pressure than it should be able to. but at this lower pressure, the MPA-3 can push the sear enough to release the bolt, but not fully have the strength to fully close the flow through the on/off. this can cause the sear to push back up against the bolt lip surface prematurely and when the bolt comes back it will scrape the bolt catch and cause premature wear. this is something that can be a potential problem in pneumag and electropnuemag designs.
another thing that causes this premature bolt wear is too short of a dwell time. this is of course, is only a problem with electropneumags, and electromags in general.
the short dwell time lets the sear come up prematurely, and it once again can scrape the sear catch lip of the bolt, causing premature bolt wear.
to find out what your minimum dwell time is, I start at 30 msec, a time that is known to be enough in most cases. then reduce your recharge time until you notice that it just starves the gun. just about 3 to 5 msec too short. then reduce your dwell time, while leaving the rof the same. if this helps the recharge, and the gun does not starve, then you know that the bolt is coming back all the way before the sear comes back and you can try to lower the dwell again. use this process and set the dwell at about 5 msec more than it needs to be. alot of times it needs to be about 20 to 25msec, so I recommend setting it to 25 to 30 msec.
I hope that was informative and not too hard to follow.
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