.308 LPK help

[eljBRD]

Hi, I am researching which parts to use for my first AR project. If I use a .308 Lower Receiver, can I use any LPK? or do .308 lowers have propietary Parts Kits?

[IGOTDIRT4U]

It depends. The pins need to be wider, and depending on who machined the lower, you may need larger diameter pins, too. Other than that, the rest is standard. In some cases you may also need a different hammer. IIRC, most cases you will need that.

Or just get a Timney drop in trigger group...

[tkmech21]

I built off a noveske lower for an armalite upper, At the time of putting my lower together parts kits were scarce. I used a RRA standard AR-15 LPK and ordered the Bolt Catch, Mag catch, front and rear takedown pins. Those are the only parts that will not cross over. DD's ranch has Armalite LPK's in stock by the way, 119.95 http://www.ddsranch.com/cart/index.p...t2i62r24pr7dv2. But it depends if your going to build Armalite or DPMS, and Armalite LPK will not work for a DPMS build. Hope this helps.

[eljBRD]

It depends. The pins need to be wider, and depending on who machined the lower, you may need larger diameter pins, too. Other than that, the rest is standard. In some cases you may also need a different hammer. IIRC, most cases you will need that.

Or just get a Timney drop in trigger group...

Thanks. That offers some more clarification. The stripped lower is from PATRIOT ORDNANCE FACTORY.... and the LPK is from DPMS. the LPK is for a .308 lower receiver... it also says in the description that it has a heavier hammer or something like that

[eaglemike]

The POF .308 lower uses the standard AR15 LPK, excpet for the front and rear take-down pins. They come with these 2 pins for the receivers I've seen, as well as the ambi bolt release parts. The take-down pins are smaller diameter than the usual .308 AR stuff.
all the best,
Mike

[dfletcher]

Thanks. That offers some more clarification. The stripped lower is from PATRIOT ORDNANCE FACTORY.... and the LPK is from DPMS. the LPK is for a .308 lower receiver... it also says in the description that it has a heavier hammer or something like that

I built a DPMS upper on a POF lower in 308. The front hinge pin is smaller and I bought a sleeve from CWS, has to be fitted with a little careful filing. The rear takedown is the same as any AR. Trigger pins, safety, bolt release and everything else is standard AR. I did use the RRA 2 stage instead of the standard issue and it has been 100% reliable.

The only 2 PITA issues I dealt with were that the detent holes were slightly undersized for the front & rear detent pins. I dressed down the standards just a bit & they work fine, I've known of one other person using the POF lower that's had the same problem. The other problem was the ambi bolt release - the spring is a bit short and underpowered to reliably move the bolt release from the off side. I used a longer spring.

Overall I didn't see much difference between the standard AR LPK and a 308.

[eaglemike]

I built a DPMS upper on a POF lower in 308. The front hinge pin is smaller and I bought a sleeve from CWS, has to be fitted with a little careful filing. The rear takedown is the same as any AR. Trigger pins, safety, bolt release and everything else is standard AR. I did use the RRA 2 stage instead of the standard issue and it has been 100% reliable.

The only 2 PITA issues I dealt with were that the detent holes were slightly undersized for the front & rear detent pins. I dressed down the standards just a bit & they work fine, I've known of one other person using the POF lower that's had the same problem. The other problem was the ambi bolt release - the spring is a bit short and underpowered to reliably move the bolt release from the off side. I used a longer spring.

Overall I didn't see much difference between the standard AR LPK and a 308.

Bolt catch and mag catch are different to some degree in the DPMS LR308 kit vs std AR (plus the take-down pins). I've been told some people can make the std stuff work, especially the magazine catch, but it varies depending on which brand receiver. This might have a little to do with why some .308 AR's run well, and some don't.
all the best,
Mike

[dfletcher]

Bolt catch and mag catch are different to some degree in the DPMS LR308 kit vs std AR (plus the take-down pins). I've been told some people can make the std stuff work, especially the magazine catch, but it varies depending on which brand receiver. This might have a little to do with why some .308 AR's run well, and some don't.
all the best,
Mike

I used a BB, so the mag catch is not on mine. But I did fit it to see if it worked (I visit OR fairly often) and it worked fine.

The standard AR 15 bolt release worked fine too, but I'm told there's a 308 type that is sturdier & for use with the much heavier 308 bolt. I eventually went with the AR 15 DPMS tactical type BHO, it fit fine on the lower but I did have to dress down the back side to make it fit properly against the side of the wider 308 upper. If the DPMS tactical BHO isn't fitted I can see that it would cause problems.

By the time I built the 308 I had already built a few 223 types, was concerned about what parts would fit, what parts would not. For the most part it was very easy and I think I overplayed the "308 is different" worry a bit.