I've gotten hold of a 7.62x39 AR upper. The lower I have free has a cassette trigger that just won't cut it on those hard Rooskie primers. It just goes click. I put in one of those "enhanced" longer firing pins and now it goes CLICK! I need a trigger where I can add a high-power spring. I want a trigger that can use the extra power spring but still have a not-terrible trigger pull. I was thinking about the LaRue MBT or the BCM PNT as the best choices. Should I consider something else?
- Thread starter AbitNutz
- Start date
The ones with the dual spring getup on the hammer.
I ran through about 8k rounds with an RRA NM trigger with no light strike troubles. Tulammo,wolf, and brown bear.
- Nov 3, 2010
- 8,661
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My 7.5 inch upper ran fine with an mbt trigger
Geissele or really any trigger that isn't a cassette/enclosed drop in. I tried a few and went back to Geissele.
Putting that heavy a spring in a trigger has the possibility of ruining the trigger pull. I'm starting to wonder if putting that kind of spring in almost any of the better triggers is going to make them all feel about the same.
It will..
I have a 7.62x39 upper and after about 500 rounds of that dirty steel cased crap there were all sorts of issues.
I ended up getting an AK pistol that's designed for that stuff, and I shoot exclusively brass cased ammo in the AR-47.
Now I use a trigger that doesn't take 10 frigging pounds to break
Trigger and disconnector spring on the MBT2S determines most of the 'Trigger Pull'.
Hammer spring has little effect on pull. The MBT2s comes with a standard strength and a higher strength Hammer spring.
The heavier spring and anX39 firing pin is about the hardest you will get the pin to hit the primer.
Hammer spring has little effect on pull. The MBT2s comes with a standard strength and a higher strength Hammer spring.
The heavier spring and anX39 firing pin is about the hardest you will get the pin to hit the primer.
A milspec trigger with do fine with surplus steel cases if you just remove the firing pin from your bcg, and use your reloading or other calipers- carefully measure the thickness of the shoulder where it stops in your bolt to allow the actual striking face of the pin to hit the primer. Put it in a drill press and "polish" off or turn the leading edge of the shoulder of the firing pin .01 to .017. I use some valve grinding compound, emery cloth, and lightly polish after to a mirror checking the measurement as material is removed.
I've built a half dozen x39's and that has always made a world of difference. You can experience going deeper, thus allowing more protrusion of the firing pin and a harder, deeper hit, but too much can overpenetrate and puncture a primer. I've set most at .015, and had success on all ammo, including the red lacquered over yellowish surplus stuff from the early 50's
Now,
if you Really wanna shoot 7.62x39, there is this one other platform that does it Very reliability...
I've built a half dozen x39's and that has always made a world of difference. You can experience going deeper, thus allowing more protrusion of the firing pin and a harder, deeper hit, but too much can overpenetrate and puncture a primer. I've set most at .015, and had success on all ammo, including the red lacquered over yellowish surplus stuff from the early 50's
Now,
if you Really wanna shoot 7.62x39, there is this one other platform that does it Very reliability...
I believe that there are a number of manufacturers who make enhanced firing pins, specifically for the 7.62x39, with longer pin protrusion.
Isn't what the "enhanced" firing pin is purported to do? I've looked at the tips of a standard and "enhanced F/P under a magnifying glass and you can clearly see exactly what you're referring to.
It's true, an AK will absolutely shoot that steel-cased ammo reliably but I'm just having a good time.
I don't know anything about those triggers or Rrugers AR's. Is anything about them proprietary?
No.
They drop in std Mil-Spec lowers. Anderson, Palmetto, Aero, Ruger.... and probably everything else too.
yes
a standard milspec trigger and the enhanced/extended firing pin is all you need. I've built 4 x39 ARs and love them. never had a single issue
EFP and any trigger with a wolff extra power spring.
if you want the power but not a crappy trigger pull, Hiperfire X2S is my pick (and currently in my x39 AR)
if you want the power but not a crappy trigger pull, Hiperfire X2S is my pick (and currently in my x39 AR)
I just put in a BCM PNT trigger with exactly that spring, a Wolff extra power. The trigger took two men and a small boy to set it off. Also getting that hammer pin installed was no joy either. On the other hand it was extremely crisp and did set off everyone of those rock hard primers.
I read an article last year that PSA was due to start making Russian 7.62x39 and 5.45x39 steel case ammo in 2023. Well,it's 2023...where is it PSA?
Mine has a hiperfire heavy gunner with a nice 4.5 ish pull combined with the extended firing pin and I haven’t had a non ammo related failure in a few thousand rounds. The only down side is my first extended firing pin died in about 1000 rounds. Hiperfire for the cost is my favorite ar trigger by a large margin.
I like the Geissele SSA-E. It will fire any hard primer you throw at it.
Steel-Cased AR Trigger (For Steel Case Ammo) - Velocity Precision Engineering
The Velocity AR Trigger "Steel Case" version features a stronger hammer and hammer spring to improve performance with steel case ammo, but can be used with traditional brass ammo as well including .22 rifles - If you shoot a lot of steel case ammo this is the trigger for you! Available in 4lb...
velocitytriggers.com I have 2 of them and may pick up a third. Especially a fan of the straight with finger stop trigger shoe.
That's the first cassette trigger I've seen for hard primers. I'm going to take a look at that.Steel-Cased AR Trigger (For Steel Case Ammo) - Velocity Precision Engineering
The Velocity AR Trigger "Steel Case" version features a stronger hammer and hammer spring to improve performance with steel case ammo, but can be used with traditional brass ammo as well including .22 rifles - If you shoot a lot of steel case ammo this is the trigger for you! Available in 4lb...
I have 2 of them and may pick up a third. Especially a fan of the straight with finger stop trigger shoe.
It easier to shorten the tail of the bolt.
easier, but incorrect practice since then you're not getting maximal force from the hammer strike.
why do you think that?
simple physics, by shortening the bolt tail, you're moving the strike point forward, which changes the angle of the hammer strike, and reduces the contact surface of hammer to firing pin.
also it's far better to replace a relatively inexpensive firing pin if you take off too much material than needing an entirely new bolt.
in either case, both aren't as good as a proper EFP
If you remove material from the front of the firing pin shoulder it does the same thing, move the firing pin forward.
With the Grendel the face of the bolt is .012" further toward the rear and the bolt is longer, does that also reduce the contact and effect the force? It's .010", about the thickness of 2 sheets of copy paper, you really think that will effect the force of the strike?
