HOW to make a magazine cut-off

9827 Views 57 Replies 11 Participants Last post by Chow, Mar 14, 2020

adas1223

Discussion Starter · Jul 24, 2017 (Edited)

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its working!

Trying to get back into airsoft, took a 5 year break. Like the title says, I have an idea for an AEG AK build with functioning charging bolt, mag empty, magazine out function. Think KWA AKR ERG. The reason i didnt go that route is that:
i like the ak 74u platform, very compact. akr is proprietary. i like real wood and stamped steel. i like to tinker/fabricate stuff. use of my own EFC/MOSFET for trigger response, not so much ROF. So far i have preordered a CM045A* coming in next month. Gate Warfet1.1 EFC with control board. 3AH 20A lion battery cells. Magnetic reed switches and 6mm neodymium magnets for switch activators.

I plan to glue magnets to the magazine and follower, then glue the reed switches to the gun itself so it will disconnect the trigger when the mag is either out, or empty/low BB's. someone on youtube has a similar setup which i borrowed the idea from.

Im custom making a 16v L-ION 3ah battery pack with LG HG2 cells which the warfet1.1 should handle fine. My aim is for realistic gun manipulation and trigger response. the gate warfet 1.1 has a pretty cool precocking feature which should lower FPS in the long run (keeps spring compressed) and create a hair trigger without the fuss of a dsg build. scratch this- you dont need precocking with a 16v battery

*Some questions im hoping you guys can help me out with is the function of the bolt charging feature once a new magazine is inserted. Im not sure if I need a relay or if this can easily be done mechanically.

Ill keep this build updated with pictures when the gun itself comes in. If you see any things i overlooked please critique my ideas.

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Chow

· #2 · Jul 24, 2017

Welcome back to the Forum adas1223!

adas1223 said:
i like real wood and stamped steel

So far i have preordered a CM035a coming in next month.

Are you sure that you want to go with the CM-035A instead of the CM-045A?

I know that the CM-045A is out of stock at a lot of places, but it may be worth waiting for. More of the externals are stamped steel, it has some better internals, the build quality is really good for what it is, and it is a VFC clone which I have come to prefer immensely. On mine, it appears that I also have more space underneath the dust cover versus the TM clones that I have had. I say that because it may help/pertain to how much space you might need with your build.

Good luck and I look forward to seeing future updates,
Chow

MNairsoft7

· #3 · Jul 24, 2017

Chow said:
Welcome back to the Forum adas1223!

Are you sure that you want to go with the CM-035A instead of the CM-045A?

I know that the CM-045A is out of stock at a lot of places, but it may be worth waiting for. More of the externals are stamped steel, it has some better internals, the build quality is really good for what it is, and it is a VFC clone which I have come to prefer immensely. On mine, it appears that I also have more space underneath the dust cover versus the TM clones that I have had. I say that because it may help/pertain to how much space you might need with your build.

Good luck and I look forward to seeing future updates,
Chow

I second this. A cm045 would be a much better option as it has a simpler disassembly and is easier to work on.

adas1223

Discussion Starter · #4 · Jul 25, 2017

Chow said:
Welcome back to the Forum adas1223!

Are you sure that you want to go with the CM-035A instead of the CM-045A?

thanks man. rechecked my order lol. it is infact AEG-CM045A! thanks for the info, i didnt realize there was that many differences. good thing i asked.

aestheics wise, i plan to design some bits in my 3d printer. maybe an extended follower so no bbs get wasted similar to the KWA.

Any recommendations on an easily dissasembled AK mid-cap? Can KWA akr mags work on this gun? it would be great if they did

if no one knows im willing to drop the $ on a mag i can tear into and mod XD

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adas1223

Discussion Starter · #5 · Jul 31, 2017 (Edited)

pencil for scale. the 6mm neodymium magnets with the micro reed switches. magnets need to get within half inch to activate the switch. very cool audible click once activated. this of course will disconnect/reconnect the trigger signal wire.

of course the warfet 1.1 waiting for the gun to arrive XD

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adas1223

Discussion Starter · #6 · Aug 28, 2017 (Edited)

CM045a came in. i was able to custom make a 20a 12.3v max 3000mah batterypack. i could fit 3AH of 16v goodness but the trigger response is god like even without the mosfet. ordering a flat trigger because the stock ak has such a long pull. to get quick triple taps i need to pull the trigger at the very end tip.

I did have to grind the 2 rivets under the cover and sides of the front block to fit the battery. no biggie.

im downgrading the spring to an m100 too once i crack it open. shoots very well so far! very pleased!

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Chow

· #7 · Aug 28, 2017

I could be wrong, but since he pre-ordered it, I would assume that he got it off of Evike. Their CM-045A's were in the pre-order status for months and only came back in stock within the past few weeks. At the time that I am posting this, they are still currently in stock for $155 shipped with the "freeship" coupon code.

Chow

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adas1223

Discussion Starter · #8 · Aug 28, 2017

Chows correct. Pre-ordered it when it was on sale for $116

adas1223

Discussion Starter · #9 · Oct 7, 2017 (Edited)

Here it is so far. 16V 3AH goodness with warfet chip fit PERFECTLY! i dont really need the pre-cocking feature as the response with 16v is more than enough. i like the Burst feature though!

Im Using the KWA 60round AKR mags which feed all bb's. I glued a magnet to the cutoff. Also used a rubber nub to keep any bb's from falling out. works like a charm!!!

I can't believe i got the Magazine empty* feature working. Gun cuts-off when there is 1 bb left. the gun will still fire without magazine though. the mag out feature will be my next project. should be more straight forward.

more to come!!

PS: i also 3d printed a "stormwerkz sight rail" which i designed so i can mount my micro red dot or t1.

PPS: flat trigger and downgraded m100 already inside

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-Spitfire-

· #10 · Oct 7, 2017

Subbed. Heavily. Like extra creamy ranch.

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adas1223

Discussion Starter · #11 · Oct 26, 2017 (Edited)

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anybody know if a switch like this exists or similar. preferably micro sized. Im a noob at circuitry. I really want a functioning bolt charge.

edit: after studying this circuit it wont work. the trigger signal was suppose to be the power. i just realized the trigger is a broken signal already lol. you cant break something already broken SMH! lol... back to the drawing board

PS: the build is going great. ill post up pics of the magazine mods i had to do for empty mag simulation. im swapping over the 3rd burst for a 900rpm automatic setting. more realistic and the rate of fire of a 16v is too much

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adas1223

Discussion Starter · #12 · Oct 29, 2017 (Edited)

Updates: rethreaded the barrel to 1/2x28 to fit my .223 muzzle device. (also shorted the barrel and re-crowned) installed a red dot rail. Modified all 3 of the KWA magazines to cut off when empty. even upside down! just added a little 'spring'. ill upload a shooting video tomorrow. have to charge the POV cam

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adas1223

Discussion Starter · #13 · Nov 5, 2017

Update: ordered 3 more KWA erg magazines. retrofitted a trigger micro switch and hair trigger mod. very glock like audible and tactile short reset. slowed down the rate of fire on full auto by 50%

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adas1223

Discussion Starter · #14 · Nov 19, 2017

Some updates

chronoing .20 @ 320fps with my m100. .30g bbs @ 265fps. VERY cqb legal.

Ordered shs 12:1 gears. my stock spur gear lost a tooth. still works but cant say no to an upgrade.

Found a new reed switch sensor made in india. i can most likely get my bolt to charge the next round with this one! can also achieve mag out cut off, AND still use high caps if i need to *crosses fingers* I'll sell my idea to an airsoft company first dibs

Ordered a magpul AK grip. hopefully i can mod it to fit the motor! this project keeps going!

also, drilled out the rivets to the scope mount to remove. that chunk of pot metal weights a ton. so did the stock steel flash hider. filling in the rivet holes with plain alu pop rivets.

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Raven1st

· #15 · Nov 20, 2017

It's been a long time since I've seen a thread with this much cool stuff in it. I may get back into AEG's and try some of this stuff.

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adas1223

Discussion Starter · #16 · Nov 28, 2017

Raven1st said:
It's been a long time since I've seen a thread with this much cool stuff in it. I may get back into AEG's and try some of this stuff.

yeah dude!

UPDATE: new sensors incoming from (Reed Relays and Electronics India Limited). these guys are awesome to hook me up with free stuff

gotta keep this WIP thread full of information if i decide to build another gun like this. Ill post more indepth pictures of the modifications (especially the micro switch trigger) once i tear apart the GB again.

PS: I have a gas shell ejecting shotgun coming in (cam870 mkII) i couldnt pass up the deal. I have 3d printed shells and 3d rifled slugs waiting to get shot!!

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adas1223

Discussion Starter · #17 · Dec 11, 2017

new sensors here! same size as previous. also, fitting a real steel AK K2 grip in OD. more vertical than a stock v3 grip

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Raven1st

· #18 · Dec 11, 2017

I was just thinking about another layer to this mod.

You know those mags that have a dingus on the feeder so it feeds all the BB’s through the hopup? What if you put a magnet in there and a sensor on the side of the hopup.
The hopup sensor will be a reverse of the magwell sensor (the magnet opens the circuit) so when the mag is in and the gun is dry (dingus is in the hopup) it cannot fire.

I hope that I didn’t make it too confusing.

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adas1223

Discussion Starter · #19 · Dec 11, 2017

that was my orignial plan! but since the KWA had a cut off nub which rises too, i couldve went either route.

but that functionality already exists on the gun. when its out of ammo and mag is in, it cannot fire. the magnet is near the reed switch.

The element i want is to have the gun not fire even if the mag is full or even when there is no magazine. you'd be forced to charge the bolt to reactivate. this is done with my new sensor being 'Bi-polar' latching type.

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Raven1st

· #20 · Dec 12, 2017

Huh, never knew KWA has that much function in their AEG's now.

Any pics of the empty mag cutoff. I've never seen one of those before.

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