GATE MERF 3.2 modification to semi only?

[Rossco66]

Has anyone ever heard of a way to mod or program the MERF 3.2 to enable semi only? I need to make my M14 a true DMR to comply with another fields rules.

Before I get Pesto to physically mod the gun, I thought I would reach out to the brain trust to see if this is possible at the fet level?

I have sent a note to GATE themselves but haven't received any reply.

Thanks in advance for any help or guidance.

Rossco

[Kos-Mos]

If you need semi-only to comply with a field rule, you need a physical mod.

The MERF has the semi-only option in programming, nothing to modify there.

[Rossco66]

I don't need to mod the semi side but I was hoping that someone has figured out how to program the auto/3 round burst into semi as well.

[wind_comm]

there's no real way to do it. best I could do is to set the 3 round burst to as short as possible, and it'll mostly shoot in only semi with the occasional double fire that nobody really minds.

[Kos-Mos]

I am sorry, I meant that you can set the burst mode to fire 1 shot only.

But as I said, most places that will enforce DMR/Semi-only rules will need a physical blocking method. Because one could reprogram the FET after chrono/check.

My favorite, non-destructive and reversible way to do it is to drill a small hole on the left-side of the mechbox to prevent the selector plate from moving past the semi- position. Install a set screw with thread lock in there and you can revert it. It does require your gun to be taken appart, so it usually counts as "permanent".

You can alternatively sand/file the section of the selector plate that interacts with the cut-off lever so that it does not lift it out of the way when in "auto" setting on the fire selector. Longer to do, but even more permanent as your really need to take the mechbox apart to change it.

[Hectic]

Yeah the only way with the kerf o's to set the 3 round burst I went the opposite way and set it as long as I could plus seeing the smart trigger to 10% what winds up ha penning is the burst/auto is so slow you can semi about 10 times faster. For most fields this is okay, especially if you are a known member in the community. Otherwise as was stated either a set screw to block the selector (either the plate or the switch) or molding of the selector plate. Another option would be to find a lower with semi only controlls then the receiver will have the hump to prevent going past semi.

[Rossco66]

As this is a G&G M14 EBR the fixes for M4 lowers isn't going to work. There is a part connected to the "paddle" selector switch that protrudes through the other side of the gearbox. It has the mechanism on it that alters the position of the selector lever and I suppose it would be the best place to work from.

That being said, if I am going to remove material, the little male tab which mates with the "selector paddle's" females slot could be sanded away and therefore neuter the ability for the "paddle" to move the selector lever at all.

Looks like Pesto is going to have to do the work and install a means to resolve the dreaded semi lock.

[Rossco66]

Reply from American Milsim:
Mitch,

If you can enable single fire via the MOSFET that will be fine. The rifle must be ONLY able to shoot semi-auto as a DMR.

Regards,

The AMS Team

A reply from GATE to my inquiry of whether or not the fet could be modded was to reduce the ROF to 30% and then make the burst the shortest time possible and see what happens.

After programming ROF to 30% and the burst time to 96ms
The result is in Auto > 1 round per trigger pull for the first 2 trigger pulls and the a 2 round burst with the 3rd trigger pull. It just repeats this cycle.

I am hoping this is good enough for American Milsim and I don't have to physically alter this rifle. I will let you know what they come back with.

[Drake]

30% ROF will give you such a sluggish trigger response, even moreso for a DMR. All to gain a tiny FPS advantage which translates into virtually nothing practical. Seems to me like a horrible tradeoff for the sake of taking the easy route.

Not trying to shit on your idea here, but take a minute to think about it. The wind up on the trigger pull is going to last forever.

[Rossco66]

Originally Posted by Drake

30% ROF will give you such a sluggish trigger response, even moreso for a DMR. All to gain a tiny FPS advantage which translates into virtually nothing practical. Seems to me like a horrible tradeoff for the sake of taking the easy route.

Not trying to shit on your idea here, but take a minute to think about it. The wind up on the trigger pull is going to last forever.

It doesn't seem too bad. I will incrementally ratchet up the ROF% and see if I can maintain the same effect on the Auto function.

If its a no go with American Milsim then the point will be moot anyway.

[Rossco66]

Apparently this result is insufficient for American Milsim.

They suggested a drop of JB Weld which can be easily filed off after the event is over. This seems like a smart compromise over removing any material from the rifle itself.

I've never worked with this stuff before but I'm assuming a drop or two of it to create a mound that will prevent the selector lever from moving into the full auto position will do the trick.

I can then reset the mosfet to 100% ROF

[Rossco66]

As the fet mod was insufficient for American Milsim I had to create a physical block to the Auto selector on the rifle.

I managed to get the Auto disabled by adding a drop of JB Weld to the top edge at the end of the selector connecting rod. This prevents the selector cam from fully rotating and engaging the Auto setting. The fix is not permanent in that the JB Weld can be filed down to restore the Auto functionality if I ever have to sell the weapon.

Case resolved for now. Hopefully Pesto will be able to put his thinking cap on to come up with a resolution to the potential of a semi-lockup occurrence that can be done easily in the field.

As it stands now, if the semi-lock occurs, I will have to open up the battery compartment and temporarily unplug the MERF and plug the battery into the motor directly. This isn't ideal given the PITA factor involved with the 6 small hex screws and the potential occurrence of this scenario in the midst of a firefight.

[chaz]

not having a single clue about how your gun looks inside (or any gun for that matter) but couldn't you buy a new selector and perm. mod it to remove full auto? That way when you sell it you can just put the original un-modded part back in? I don't know, I am no tech.

Would a different MOSFET help remove the semi-lock issue? Something that ensures a complete cycle each pull?

[Kos-Mos]

Originally Posted by Rossco66

As the fet mod was insufficient for American Milsim I had to create a physical block to the Auto selector on the rifle.

I managed to get the Auto disabled by adding a drop of JB Weld to the top edge at the end of the selector connecting rod. This prevents the selector cam from fully rotating and engaging the Auto setting. The fix is not permanent in that the JB Weld can be filed down to restore the Auto functionality if I ever have to sell the weapon.

Case resolved for now. Hopefully Pesto will be able to put his thinking cap on to come up with a resolution to the potential of a semi-lockup occurrence that can be done easily in the field.

As it stands now, if the semi-lock occurs, I will have to open up the battery compartment and temporarily unplug the MERF and plug the battery into the motor directly. This isn't ideal given the PITA factor involved with the 6 small hex screws and the potential occurrence of this scenario in the midst of a firefight.

I had a similar think process when I started building my SR25...
Best "solution" I found was to install a small switch that jumps the trigger contacts somewhere hard to access with a mag on (in my case, it was inside the magwell, beside the mag catch.

If you can't access it with a mag in, they should let you have this as a safeguard.
Leave the GATE in Safe-Semi-Auto mode, so this works.

[Rossco66]

Originally Posted by chaz

not having a single clue about how your gun looks inside (or any gun for that matter) but couldn't you buy a new selector and perm. mod it to remove full auto? That way when you sell it you can just put the original un-modded part back in? I don't know, I am no tech.

Would a different MOSFET help remove the semi-lock issue? Something that ensures a complete cycle each pull?

Getting another part would mean sourcing it & shipping it, exchange rate etc.. JB Weld was $10 bucks at crappy tire. To reinstate the original functionality I just have to file down the weld material back down to the original aluminum and voila.

I don't think the fet will solve the semi lock issue. I think being smart on the trigger (always fully pull the trigger all the way back) will go along ways to avoiding the issue altogether. Pesto has suggested a bypass switch which I have to figure out how to tech and create now. lol