Understanding this board's consensus about uppers, BCGs, etc--what of LPKs?

[rojocorsa]

So thanks to this site, I learned that not all ARs are created equal and more importantly the "why."


The AR I want to get when funds permit is a BCM for example. I'm set on that.


But now, I'm curious---which companies make Tier 1 grade lower components? I don't think I've ever seen info on which parts to use if this is the case. I notice that a lot of the mainstream brands carry and sell LPKs.

So what I'm basically trying to ask is: Does it matter if a lower has a standard FCG made by RRA, Stag, etc?

I've read through a lot of the stickied info here, and I don't think I've seen LPK quality really addressed, so I hope this isn't a dupe.

[TehLlama]

LPKs are a case where parts aren't parts. A couple of the DPMS lowers I own can do some cool tricks that aren't really desired (can put safety on with hammer forward, slightly large roll pin for bolt catch makes a BAD lever super stable, but took some breaking in to function at all w/ and w/out the BAD).

Given that LPK part failures aren't usually field repairable, and that really low end ones can causes doubles or other NFA no-no type malfunctions, since so many of the really good LPKs are very affordably priced, just get a good one.

Colt, BCM, DD, LMT - or one that uses parts from these. I'd say STAG/CMT is the minimum where you should be looking, my experiences with cheaper ones tell me that the reduced cost is from lesser QC and/or cutting corners.

[Eurodriver]

LPKs are a case where parts aren't parts. A couple of the DPMS lowers I own can do some cool tricks that aren't really desired (can put safety on with hammer forward, slightly large roll pin for bolt catch makes a BAD lever super stable, but took some breaking in to function at all w/ and w/out the BAD).

Given that LPK part failures aren't usually field repairable, and that really low end ones can causes doubles or other NFA no-no type malfunctions, since so many of the really good LPKs are very affordably priced, just get a good one.

Colt, BCM, DD, LMT - or one that uses parts from these. I'd say STAG/CMT is the minimum where you should be looking, my experiences with cheaper ones tell me that the reduced cost is from lesser QC and/or cutting corners.

I put a DPMS LPK in two of my Spikes lowers about 1.5 years ago. One worked totally fine, and I actually like the trigger pull alot. The other one had some issues. The mag catch would "stick" in the receiver, the safety switch after about a month would spin around in circles, and the parts had a tendency to rust (even when next to all my other firearms, the only things that got rusty would be the DPMS LPK).

I have since swapped out the bolt release, selector switch, trigger, and mag catch assembly with some Daniel Defense parts. I am fairly confident even DPMS can't screw up pin detents and springs, but we'll have to see because they only way I'm replacing my front one is if it fails.

[Exiledviking]

Seek (orange "Search" button near the top of the page) and ye shall find:

https://www.m4carbine.net/showthread.php?t=91218

[rojocorsa]

Seek (orange "Search" button near the top of the page) and ye shall find:

https://www.m4carbine.net/showthread.php?t=91218

Thanks!

[Exiledviking]

I use the Google search more than anything else. On Google, type in "site:www.m4carbine.net" followed by whatever you are searching for, ie "lower parts kit".

It looks like this - http://www.google.com/search?q=site%3Awww.m4carbine.net+LPK&rlz=1I7GGLL_en&ie=UTF-8&oe=UTF-8&sourceid=ie7#hl=en&rlz=1I7GGLL_en&sclient=psy-ab&q=site:www.m4carbine.net+lower+parts+kit&pbx=1&oq=site:www.m4carbine.net+lower+parts+kit&aq=f&aqi=&aql=&gs_sm=s&gs_upl=93l3594l0l6135l18l12l1l0l0l1l735l4124l2-1.1.1.4.1l9l0&bav=on.2,or.r_gc.r_pw.,cf.osb&fp=7f1b6f53b47cc533&biw=1280&bih=697

[rojocorsa]

I use the Google search more than anything else. On Google, type in "site:www.m4carbine.net" followed by whatever you are searching for, ie "lower parts kit".

It looks like this - http://www.google.com/search?q=site%3Awww.m4carbine.net+LPK&rlz=1I7GGLL_en&ie=UTF-8&oe=UTF-8&sourceid=ie7#hl=en&rlz=1I7GGLL_en&sclient=psy-ab&q=site:www.m4carbine.net+lower+parts+kit&pbx=1&oq=site:www.m4carbine.net+lower+parts+kit&aq=f&aqi=&aql=&gs_sm=s&gs_upl=93l3594l0l6135l18l12l1l0l0l1l735l4124l2-1.1.1.4.1l9l0&bav=on.2,or.r_gc.r_pw.,cf.osb&fp=7f1b6f53b47cc533&biw=1280&bih=697

Thank you for the tip, as I've never had good luck with forum based searches in general. I shall keep this one in mind.

[C4IGrant]

So thanks to this site, I learned that not all ARs are created equal and more importantly the "why."


The AR I want to get when funds permit is a BCM for example. I'm set on that.


But now, I'm curious---which companies make Tier 1 grade lower components? I don't think I've ever seen info on which parts to use if this is the case. I notice that a lot of the mainstream brands carry and sell LPKs.

So what I'm basically trying to ask is: Does it matter if a lower has a standard FCG made by RRA, Stag, etc?

I've read through a lot of the stickied info here, and I don't think I've seen LPK quality really addressed, so I hope this isn't a dupe.

For LPK's, I rank them in this order:

Best:

Colt

Very Good:

BCM
G&R Tactical
LMT
Noveske
KAC
DD



C4

[polydeuces]

Grant,
where does the Colt LPK differ from yours (LMT?) or DD?
So far I've been exceptionally pleased with both, and am not sure what would justify the additional cost.
Is it an issue of ever so slightly better fit, as I can't imagine there's any difference in material?
Thanks.

[SeriousStudent]

I have been quite pleased with the G&R parts kits. I have assembled or helped assemble 5 lowers with them. I also have a Colt 6920 and a BCM carbine to compare them to. I had an LMT, but sold it to a friend. So that is a sample size of eight. Not huge, but big enough to perhaps see a trend.

All of the G&R LPK's worked very well, with no issues. The selector movement was positive and precise. I felt the triggers were also crisp, and a good weight for a defensive carbine.

I really do like the fact that I can add a few extra springs and detents with it, and build up my spare parts box with little overhead.

[Inkslinger]

Op you won't be able to get a stripped bcm lower. If you buy from bcm directly or from Grant you can be guaranteed a high quality lpk.

[C4IGrant]

Grant,
where does the Colt LPK differ from yours (LMT?) or DD?
So far I've been exceptionally pleased with both, and am not sure what would justify the additional cost.
Is it an issue of ever so slightly better fit, as I can't imagine there's any difference in material?
Thanks.


They have the TDP.




C4

[wahoo95]

Is it not possible to reverse engineer TDP?

[C4IGrant]

Is it not possible to reverse engineer TDP?

Somewhat. The biggest problem with doing this is tolerance stacking.


C4

[rojocorsa]

Op you won't be able to get a stripped bcm lower. If you buy from bcm directly or from Grant you can be guaranteed a high quality lpk.


Yeah, I wasn't sure about that. However the bigger reason I made this thread is because I just had no clue about LPKs in general.

If anything, it seems like the same rules of thumb apply regarding the companies. Glad it's as simple as that.

[rojocorsa]

I have two other questions; I don't want to make a whole new thread, so I'll just ask here if that's OK.


1)
Looking at the BCMs standard vs the BHF, is it worth getting the BHF for the additional $90? What marginal benefit does this add to the rifle? Does it aid in accuracy, or does it only make the barrel last longer?

2)
Also, Something like a Troy folding rear sight or a Magpul MBUS---are these units OK to use as standalone rear sights, or am I better off with a det. carry handle? I just figured that by buying the troy or the MBUS, that I'd knock 2 birds with one stone.

Thanks
Rojo

[C4IGrant]

I have two other questions; I don't want to make a whole new thread, so I'll just ask here if that's OK.


1)
Looking at the BCMs standard vs the BHF, is it worth getting the BHF for the additional $90? What marginal benefit does this add to the rifle? Does it aid in accuracy, or does it only make the barrel last longer?

Yes. They are more accurate IMHO.


2)
Also, Something like a Troy folding rear sight or a Magpul MBUS---are these units OK to use as standalone rear sights, or am I better off with a det. carry handle? I just figured that by buying the troy or the MBUS, that I'd knock 2 birds with one stone.

Thanks
Rojo

Yes (Troy is a better choice as a standalone).



C4

[rojocorsa]

Thanks Grant.

And thanks for reaching out to us California gun owners, it's refreshing to see that for a change. I appreciate that.