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DMR semi auto locking?

straffham

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Ok I've just about finished a full internal upgrade on my M16A3 (tbb, helicals, hi torque motor, quick change spring etc) with the idea of using as a DMR. Currently running sub 350fps just to get used to using it semi auto, but with ability to switch to full if it gets too annoying lol!

Anyway question I have is if I go the whole hog to 400+fps how do people lock their gearboxes to semi only? Just via a mosfet, or by some physical means?

Cheers.

 
lack of knowledge :P on my part

 
Last edited by a moderator:
cut off part of the selector lever I believe
if you don't know the answer, why bother posting?

Most permanent way to do it is to remove the part of the selector plate that moves the cut-off lever out of the way;

1-Parts.jpg


The bit just to the left of the top arrow is what you need to remove, probably about 5-6mm. When the gun is set to auto, the selector plate moves backwards along the gearbox and pushes that little lever which disengages the cutoff lever, with no cutoff lever the trigger doesn't get disengaged after each shot and you get full auto.

 
failing that, a burst wizard style MOSFET with both semi and auto set to single shot should do the job. Though some sites apparently insist upon the gun being mechanically locked to semi, never experienced it myself though, how would they check?!

 
I have both a mosfet and a mechanical lock on my M27. The mosfet improves the trigger response drastically and they can be used to lock to semi, however the plug in ones that go between battery and motor can be bypassed easily.

If your DMR had one of them and got checked by a marshal, you could easily remove it afterwards and plug the battery straight into the trigger contacts as there will still be a mini tamiya/deans connector the mosfet plugs into. This would give you a 400-425 fps gun firing in automatic, which is against most site rules and I believe it's against the law to have an automatic AEG over 350. Not 100% sure though.

 
Last edited by a moderator:
if you don't know the answer, why bother posting?

Most permanent way to do it is to remove the part of the selector plate that moves the cut-off lever out of the way;

1-Parts.jpg


The bit just to the left of the top arrow is what you need to remove, probably about 5-6mm. When the gun is set to auto, the selector plate moves backwards along the gearbox and pushes that little lever which disengages the cutoff lever, with no cutoff lever the trigger doesn't get disengaged after each shot and you get full auto.
sorry, my bad. No idea really, bit of a stupid thing to do.

 
I have both a mosfet and a mechanical lock on my M27. The mosfet improves the trigger response drastically and they can be used to lock to semi, however the plug in ones that go between battery and motor can be bypassed easily.

If your DMR had one of them and got checked by a marshal, you could easily remove it afterwards and plug the battery straight into the trigger contacts as there will still be a mini tamiya/deans connector the mosfet plugs into. This would give you a 400-425 fps gun firing in automatic, which is against most site rules and I believe it's against the law to have an automatic AEG over 350. Not 100% sure though.
Going in the same vein though you could just reprogram the hard wired mosfet to go back to safe-semi-auto, all it normally takes is a couple of trigger pulls.

As for a full auto AEG over 350FPS being illegal, WTF are you smoking? I want some.

 
if you don't know the answer, why bother posting?

Most permanent way to do it is to remove the part of the selector plate that moves the cut-off lever out of the way;

1-Parts.jpg


The bit just to the left of the top arrow is what you need to remove, probably about 5-6mm. When the gun is set to auto, the selector plate moves backwards along the gearbox and pushes that little lever which disengages the cutoff lever, with no cutoff lever the trigger doesn't get disengaged after each shot and you get full auto.
Cheers for that, very helpful, and I guess if it was needed to convert back to full auto at some point I'd just need a new selector plate. I hear what you're saying about the mosfet being able to be reprogrammed and possibly technically not being allowed without a mechanical semi only setting, guess only way marshalls would know would be to catch you red handed if someone tipped them off, but can't see them asking you to dismantle your gun somehow? As the gun isn't currently running a mosfet this mod looks like the way forward anyway, with the possibility of a sector gear monitoring mosfet at some point (though it does have good enough trigger response as is for my old & slow skill levels!)

 
I have both a mosfet and a mechanical lock on my M27. The mosfet improves the trigger response drastically and they can be used to lock to semi, however the plug in ones that go between battery and motor can be bypassed easily.

If your DMR had one of them and got checked by a marshal, you could easily remove it afterwards and plug the battery straight into the trigger contacts as there will still be a mini tamiya/deans connector the mosfet plugs into. This would give you a 400-425 fps gun firing in automatic, which is against most site rules and I believe it's against the law to have an automatic AEG over 350. Not 100% sure though.
Cheers, yeah mosfet is a possible future addition once I'm used to using the gun in semi only, if I find the trigger response still needs improving, but the mechanical means looks the way forward certainly as a first step as don't want any chance of it reverting to full auto with a 400+fps spring.

 
yeah, changing it back is as simple as putting a new selector plate in. I'd recommend a MOSFET regardless though, without a way to release the cutoff lever if you get a V2-lockup from firing on semi too rapidly you'll need to take the grip off to release the gearbox tension!

 
Am I right in assuming that with an active braking mosfet the anti reversal lever could be removed altogether?

 
yes/no, depends on the MOSFET, without some way of monitoring cycle completion (like a spectre, chimera or ASCU) I'd leave the ARL in to stop the gearbox potentially getting braked with the spring all the way back!

 
yeah, changing it back is as simple as putting a new selector plate in. I'd recommend a MOSFET regardless though, without a way to release the cutoff lever if you get a V2-lockup from firing on semi too rapidly you'll need to take the grip off to release the gearbox tension!
Yeah thats something I hadn't considered tbh!

 
Thread necro time!

Just thinking out loud - if you do get a lock up from semi auto only; normal course of action is a quick burst of full auto.

If this does happen to a mechanical semi auto mod, could you strip the top receiver off, and push the selector plate rearwards manually to fire it off on full auto?

 
not gonna be a popular opinion: but lock/limit the selector ^^

I have a burst wizard but never really been a fan of it.


also if there is a way to pop it back to auto easily using a tool you will save a lot of hassle it if the gearbox would lock up.

 
^^ that's what I would do. Small black tactical screw. Just be sure your local site would be ok with it first.

 
if you go down the mosfet route there are pro's and cons......

best pro example I can think of is like with a prog mosfet

you can set the 3-7 rnd burst to 1 rnd burst

in this mode you need to ensure the delay from burst to auto is set to max

Resume full auto delay to 1 sec or more

hence if you have the sod in auto by mistake as long as you don't hold trigger down longer than 1 sec she will only fire 1 shot burst

Another advantage is if you get a lockup in the cut off lever dead zone - you can switch to auto and she will fire 1rnd burst even if cut off half raised

NOTE - some sites state electric/mosfet/burst lock is not allowed on DMR's

If that is the case then mechanical lock is needed but still use a basic mosfet....

Why - well if you fit a safe but hidden micro-switch say in battery compartment

basically another trigger switch circuit but out of the way so can't be used in game easily

Then if you get a lock-up - you can press the micro-switch which will in effect be a full auto switch (not governed by cut off lever)

So if on mechanical lock - the gun locks...

you could retire briefly out into dead zone, remove mag, carefully aim gun away or to ground, hit switch and not have to strip stuff down

(can't really go to safe zone coz clearing gun with a bb in chamber is not allowed coz it is fucking dangerous in safe zone)

Anyway - there are some ideas if making a dmr - deffo mofet & extra hidden micro-switch to clear lockups

 
If you've programmed your MOSFET to safe/semi/semi and a site asks if it's mechanically locked just say 'yes', what are they going to do? force you to open it up and prove it? They'll ask you to switch it to auto and pull the trigger, if it cycles once and stops then it's locked to semi.

 
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