DPMS type 308 AR Question

[AlterEgo]

Gents,

I have a CMMG 308 AR lower (takes DPMS type mags), I am in the process of picking a trigger, and was going to use the KNS anti-rotation type hammer/trigger pins.

Not sure if this will fit due to the proximity of an external radius near the hammer pin location.

Do any of you have this type of lower and will the KNS anti-rotation pins fit?

 

[AXEMAN]

Re: DPMS type 308 AR Question

pics? of the receiver just out of curiousity

 

[ORD]

Re: DPMS type 308 AR Question

The Mk3 receivers are a little weird about the radius cuts in that area. While the one on the left of the receiver might be okay, I would bet that because of the radius on the right behind the mag release will be the one that the KNS pins will not fit properly around (that applies to both the Gen 1 "dogbone" pins and the newer Gen 2 pins). You can lightly modify the pins to fit around the radius areas without much trouble...I have done this with other receivers in the past to get the Gen 2 KNS pins to fit properly (because of the amount of material to work with, I don't know that the dogbone pins will work at all). You can do it by hand or with a LIGHT touch from a dremel and just a few minutes work. A little black touch up pen and they look fine.

 

[madcratebuilder]

Re: DPMS type 308 AR Question

ORD, any chance you can post a pic of that mod? I'm thinking about getting a set of anti-rotation pins for my ArmaLite lower.

 

[Zebra644]

Re: DPMS type 308 AR Question

Just and idea, I dont know if it will work but how about using a drop in self contained trigger unit like a Timeny or Wilson Combat, ( just for example only ) that have the springs in the rear of the unit that after being installed will keep the pins from rotating?

 

[AXEMAN]

Re: DPMS type 308 AR Question

read my timney thread. timneys use set screws to raise the trigger body and put pressure on the pins and retain them that way. i installed an ar-10 timney in my dpms and it wont work without modification to the hammer. when the BCG is cycled, the trigger is too tall and impedes the BCG's travel signifigantly. ill have to alter it. others have no issue. timney said while they do not reccomend it, it is mine and i can do what i want with it. and they were aware of the issue. he claimed it was the front area of the inside of the receiver that was at fault due to not letting the hammer move. i saw no issue in that area.

but the anti walk pins, you can always send them back. i would make them fit with a file, dremel and emery paper.

 

[ORD]

Re: DPMS type 308 AR Question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: madcratebuilder</div><div class="ubbcode-body">ORD, any chance you can post a pic of that mod? I'm thinking about getting a set of anti-rotation pins for my ArmaLite lower. </div></div>

I don't have any pics handy, but with an Armalite lower (either an AR-10 or M-15), you will NOT need to alter the retainers one bit.

As another thought to this whole thread...95% of the people that I see who install or who want to install KNS pins have ZERO need to do so. The KNS pins, while they can be used in any AR-type rifle/carbine, are really only necessary for rifles that are: 1) used in full auto or burst modes; 2) on 9mm, 45acp and other "blowback" type setups where a significant amount of additional stress/strain is placed on the trigger/hammer pins; and 3) if you are running your AR suppressed.

 

[AlterEgo]

Re: DPMS type 308 AR Question

I wanted to use the anti-rotation pins just as an added durability measure.

Here's a pic (or link)of the lower:
http://cmmginc.secure-mall.com/item/CMMG-MK-3-.308-Lower-1307

I've been reading up on the SR Gold trigger and am thinking about it... looks like it uses the standard pins..

 

[Unknown]

Re: DPMS type 308 AR Question

I put the anti-rotation pins on my LR-308 along with the JP trigger. No problems at all. Trigger pull is a decent 4 pounds.

 

[B y r o n]

Re: DPMS type 308 AR Question

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: AlterEgo</div><div class="ubbcode-body">I wanted to use the anti-rotation pins just as an added durability measure.

Here's a pic (or link)of the lower:
http://cmmginc.secure-mall.com/item/CMMG-MK-3-.308-Lower-1307

I've been reading up on the SR Gold trigger and am thinking about it... looks like it uses the standard pins.. </div></div>

I just put this trigger in an AR I'm building and liked the safety of it. I saw a video of a RR 2-stage letting the hammer fall when banged. This trigger is constructed so that the hammer will be caught and not allow it to fall until the trigger is pulled.

I haven't fired a single round with with it yet but it is light, crisp and has the shortest reset of any trigger out there for an AR based rifle. I'll be picking up a 308 based receiver set shortly and in all likelihood will be dropping a Gold Trigger in it as well.