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Binary Triggers







DonTom

Obsessed Member
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2019 Supporter
#1
The talk about binary triggers started in the 5.7 x 28 thread in this section. I think it will be best if I start a new thread on this subject.

Anyway, it looks like I will get the binary trigger in a day or two. By the tracking number, it's now in Miden, NV, not far from here.

I plan on putting it a CMMG rifle that I will build from this upper. With those special 40 round magazines, I assume it's designed for a regular AR-15 lower. At first, I was going to install the binary trigger in my CMMG Banshee MK57 pistol, but I decided to leave it as is and build up a 5.7 rifle with the new binary trigger. The 16.1" CMMG upper is now out to be painted (Titanium), so I assume I will get it soon as well.

Anybody here have much experience with binary triggers? I hear the speed of the bolt is somewhat critical. Will a normal AR-15 buffer spring and such be okay in a 5.7 rifle with a binary trigger?

-Don- Reno, NV
 
#2
Had two friends that had them in their AR's.

IMO, gimmicky junk.

They both had a LOT of trouble getting them to function as they were supposed to, and even then, neither one of them could do a full mag dump any faster than I could with my standard mil-spec trigger with lightened springs, or Geiselle.
 

DonTom

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2019 Supporter
#3
Had two friends that had them in their AR's.

IMO, gimmicky junk.

They both had a LOT of trouble getting them to function as they were supposed to, and even then, neither one of them could do a full mag dump any faster than I could with my standard mil-spec trigger with lightened springs, or Geiselle.
I tried one recently and I thought it worked quite well. Perhaps they have been improved since your friends purchased them? And which one did they have?

The one I have coming in is this one.

However, the one I tried out was this one.

Anyway, after I get mine installed, I will post a message here. If it won't work correctly in my CMMG 5.7 rifle, I will try it out in an AR15 and report back here again.

-Don- Reno
 
#5
Fostech Echo trigger with $10 trigger spring upgrade will give it a 3.5 pound pull and make it fast as hell to drop 60 round mags. I just installed on 3rd AR because i love having 3rd echo selector option. Once you have it down standard trigger AR's stay at home. Very smooth to shoot and no single pull triggers can come close. The only down side is it won't work with 22 conversion or cheap ammo.
 

DonTom

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2019 Supporter
#6
Fostech Echo trigger with $10 trigger spring upgrade will give it a 3.5 pound pull and make it fast as hell to drop 60 round mags. I just installed on 3rd AR because i love having 3rd echo selector option. Once you have it down standard trigger AR's stay at home. Very smooth to shoot and no single pull triggers can come close. The only down side is it won't work with 22 conversion or cheap ammo.
The one I am buying says "Works in most AR platforms and calibers including 5.56 NATO, 308 Win, 300 BLK, 9mm, Rimfire, etc.... "

If it really will work in a 22, that will make it cheap to waste ammo. But I want to try mine in 5.7.

-Don- Reno
 

Janizary

Geth Prime
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#7
The BFSIII will work in a rimfire AR conversion or dedicated AR22 upper. No special parts or FA rimfire carrier like the Fostech Echo requires.

My little dedicated AR22 upper (using either CMMG mags, or M&P15-22 mags with the Redi-mag adapter) runs like a little buzzsaw with my BFSIII.
 

42tula

uber Member
#8
BFSIII for the win. Use the red trigger spring, and a standard hammer spring and it’s at a 5lb pull. The blue hammer spring got me some light primer strikes. KNS pins do seem to help with the trigger pull weight a minor amount.

For .22 upper / conversion kit - standard carbine spring and buffer.
For 9mm upper - standard carbine buffer and spring.
For a 5.56 upper there is some fine tuning as it’s fairly common to outrun the bcg. My advice is to have a midlength or rifle gas system, with a lightweight bcg - aimsurplus makes a very good one that is half the cost of the Faxon and just as good.
For .308 upper use the orange spring, and get a second job to pay for the ammo you will run through.

You will definitely need a VFG or some sort because the muzzle likes to climb a bit depending on caliber used.
 

DonTom

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2019 Supporter
#9
BFSIII for the win. Use the red trigger spring, and a standard hammer spring and it’s at a 5lb pull. The blue hammer spring got me some light primer strikes. KNS pins do seem to help with the trigger pull weight a minor amount.

For .22 upper / conversion kit - standard carbine spring and buffer.
For 9mm upper - standard carbine buffer and spring.
For a 5.56 upper there is some fine tuning as it’s fairly common to outrun the bcg. My advice is to have a midlength or rifle gas system, with a lightweight bcg - aimsurplus makes a very good one that is half the cost of the Faxon and just as good. For .308 upper use the orange spring, and get a second job to pay for the ammo you will run through.
What would you suggest for 5.7 x 28 ?

You will definitely need a VFG or some sort because the muzzle likes to climb a bit depending on caliber used.
Yes, I was planning on a forward grip, one of the reasons I decided to put the Binary trigger in a rifle instead of the hassle of registering my CMMG pistol as a SBR.

My binary trigger will be delivered TODAY! It's now out for delivery. I have to stay home all day just to sign for it. If it gets here in time, I will go buy a lower receiver and other stuff to put the rifle together, but my 5.7 x 28 mm upper won't be here for a week or so. But since it uses a standard AR15 lower, but with special magazines for the 5.7 round to fit in a standard AR15 lower, I should be able to simply change the upper and the magazine to go from 5.56 to 5.7 if the other parts can stay the same.

-Don- Reno
 

42tula

uber Member
#10
I know what you mean Don, I have the Mean mags 9mm conversion kit for the pmags since I’m running an CMMG upper assembly (8” bbl, and CMMG bolt combo, with AP XL receiver).

You're right changing calibers is as easy as the pivot and take down pin pushed out and the 5.56 upper popped on. Then just change the mag to the corresponding caliber upper.

As far as what combo to use for the 5.7x28 to be honest I don’t know. It is still a smaller cartridge, but is a high pressure round. I’d start with the standard buffer and spring, and then if you’re outrunning the bcg try some Springco springs. The white / red intermediate or the blue enhanced might what you need.

Speaking of out running the bcg, when I had first received the BFS I tried to make it go as fast as possible. In reality, you just need to have a good “moderate” tempo to make it run like crazy. Slapping the trigger rapidly accounted for more of the issues than the mechanical issues it probably had.
 

DonTom

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2019 Supporter
#11
I know what you mean Don, I have the Mean mags 9mm conversion kit for the pmags since I’m running an CMMG upper assembly (8” bbl, and CMMG bolt combo, with AP XL receiver).

You're right changing calibers is as easy as the pivot and take down pin pushed out and the 5.56 upper popped on. Then just change the mag to the corresponding caliber upper.

As far as what combo to use for the 5.7x28 to be honest I don’t know. It is still a smaller cartridge, but is a high pressure round. I’d start with the standard buffer and spring, and then if you’re outrunning the bcg try some Springco springs. The white / red intermediate or the blue enhanced might what you need.

Speaking of out running the bcg, when I had first received the BFS I tried to make it go as fast as possible. In reality, you just need to have a good “moderate” tempo to make it run like crazy. Slapping the trigger rapidly accounted for more of the issues than the mechanical issues it probably had.
Yeah, I figure I won't outrun the BCG if I get used to what speed to press and let go of the trigger, might take some practice. I hope to be able to leave everything the same as I change uppers from 5.56 to 5.7.

-Don- Reno
 

42tula

uber Member
#12
Yeah, I figure I won't outrun the BCG if I get used to what speed to press and let go of the trigger, might take some practice. I hope to be able to leave everything the same as I change uppers from 5.56 to 5.7.

-Don- Reno
If that’s the case, I’d grab a blue Springco spring
 

DonTom

Obsessed Member
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2019 Supporter
#13
If that’s the case, I’d grab a blue Springco spring
Okay, I will try one of these.

Thanks for the info. When I get it all together and try it out, I will post here how it all worked out.

It probably won't be for a couple of weeks because I am headed to my other house in a couple of days where stuff such as binary triggers are illegal.

I expect to get my binary trigger any minute. I hope to have a little time after it comes in so I can go buy what I need at a local gun shop, such as the lower receiver to install it in.

-Don-
 

7.62

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#15
My BFS-lll is no gimmick, no issues and love it big time on my 11.5. Only downside is $$$$$$$$ raty tat tat tat $$$$$ need another case of ammo...LOL. Tat tat tat tat
 

DonTom

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#16
Looking forward to it. Which 5.56 upper / barrel length are you going to be using?
Long enough to be a legal rifle. 16.1" for my 5.7 x 28. For 5.56, the AR-15 barrels I now have are all 20". BTW, I already received my binary trigger. It came with an extra strong spring for the rifle stock. I just came back from buying a lower receiver to install the binary trigger in.

-Don- Reno, NV
 

42tula

uber Member
#17
That’s awesome Don, I apologize I steered you into the blue springco. You may not need it after all, unless you’re using a carbine receiver extension.
 
#18
I have run the Franklin and they are no problem and almost as fun as my machine guns just 10 to 20 grand less... Certainly not junk... And hey if you can't afford to dump some money into ammo... then go get a real job... lol
 

DonTom

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#19
That’s awesome Don, I apologize I steered you into the blue springco. You may not need it after all, unless you’re using a carbine receiver extension.
Not a big deal, no doubt it will get used someday.

I didn't expect the spring to come with it either.

-Don- Reno
 
Last edited:
#20
I have a Franklin Arms BFS-III, no problems. I use the lower on pistol length uppers, one in 22 lr and the other .223. Works flawlessly. Double taps with the AR are near instant and group astonishingly well, within a couple of inches at any reasonable home defense distance. Beyond that, other than just fun, the utility of mag dumps gets a little blurred.

Unfortunately, if you're a trigger snob, there's no practical way to adjust out trigger over travel, as the over travel is necessary to reset the mechanism. That was a bit disappointing, as I like nice triggers.