Are there really any major differences in a lower parts kit?





tuolumnejim

Very Active Member
Forum Supporter
#1
Have a new upper on the way so I want to cobble a new lower together. But I'm seeing so many differing prices in lower parts set its not funny.
 

LVTrenton

Living the dream
#2
The better name brands have better quality control, so you are less likely to get an out of spec part. I know that some of my cheaper builds have been lackluster - pins and switches don't move as freely as I think they ought to in some cases. Now I just pay a little extra for a name brand I trust - I choose Sons of Liberty Gun Works' Blaster Guts, which has an upgraded trigger as standard. Your money, your guns - your call. https://www.primaryarms.com/sons-of...-lower-parts-kit-and-liberty-fighting-trigger
 

usmcnye

Aim Small Miss Small
#3
Outstanding question. I have used DPMS, CMMG and Aero Precision lower kits before (Brownells: $56.64, $68.99 & $82.99); functionality great, no broken or worn out parts yet. I noticed Geissele Automatics "Ultra-Duty Lower kit" and BAD lower kit (Brownells: $129.99 & $125.99). All my AR builds have Geissele triggers; outstanding triggers. If I had been aware of the Geissele lower kits several years ago, I probably would have bought and installed. I have installed Battle Arms Development (BAD) barrel, another great company too.

I hope someone will respond that has experience with the higher priced lower parts kits; would love to get insight to quantify if the higher price really equates to higher quality. To recap, the functionality of my lowers has been without problems for several years so far. My only malfunction was from my oldest AR; problem was the ejector in the bolt, as part of the bolt carrier group, manufactured by LMT.
 

4x4Brit

Worktruck Driver
#4
I prefer to use LPK’s from better manufacturers. Less out of spec parts as mentioned and higher quality materials used, ie no MIM. The one thing I have noticed over the years with higher quality LPK’s is the takedown pins. They slide out easily, no using a punch to get them out!
 

usmcnye

Aim Small Miss Small
#5
I prefer to use LPK’s from better manufacturers. Less out of spec parts as mentioned and higher quality materials used, ie no MIM. The one thing I have noticed over the years with higher quality LPK’s is the takedown pins. They slide out easily, no using a punch to get them out!
Who do you consider to be better manufacturers? Some pins (like Aero Precision) are slightly longer to make it easier to push out by hand.
 

4x4Brit

Worktruck Driver
#7
Who do you consider to be better manufacturers? Some pins (like Aero Precision) are slightly longer to make it easier to push out by hand.
LMT, Colt, Daniel Defense, BCM and ALG/Giessele.

I have used all of the above with the exception of BCM. I would rate LMT as the best fit and quality but there probably isn’t much between those. I hear SOLGW and Sionics are very well regarded also.
 

tdyoung58

Well-known member
Forum Supporter
2019 Supporter
#9
I use Odin kits, never a problem with them.
I do add anti-walk pins instead of the regular pins.

Avoid PSA parts
 

usmcnye

Aim Small Miss Small
#13
I use Odin kits, never a problem with them.
I do add anti-walk pins instead of the regular pins.

Avoid PSA parts
The only anti-walk pins I am aware are trigger pins; I could not find anti-walk pivot / takedown pins. Odin lists their lower parts kit at $59.99; seems to be a good quality product (claims many parts are machined steel).

I would be very concerned about too loose pivot / takedown pins; these pins should be in the sweet spot (tight but not overly snug). If one does not want to use an object to help push out pivot / takedown pins; extra-long pins that have a larger grabbable head and longer length are available as stand-alone products. I would not want, nor seek out, pivot / takedown pins that are loose; it is possible that loose pins could be an issue with the lower receiver and not the pins.
 

tdyoung58

Well-known member
Forum Supporter
2019 Supporter
#14
The only anti-walk pins I am aware are trigger pins; I could not find anti-walk pivot / takedown pins. Odin lists their lower parts kit at $59.99; seems to be a good quality product (claims many parts are machined steel).

I would be very concerned about too loose pivot / takedown pins; these pins should be in the sweet spot (tight but not overly snug). If one does not want to use an object to help push out pivot / takedown pins; extra-long pins that have a larger grabbable head and longer length are available as stand-alone products. I would not want, nor seek out, pivot / takedown pins that are loose; it is possible that loose pins could be an issue with the lower receiver and not the pins.
Yeah, trigger pins are what they are. I do like the YHM extended take down pins.
I also add a set screw to the rear takedown pin to prevent it from flying ... Iol
 

CaptKurt

Those who dare, win!
Forum Supporter
#16
I have tried probably 5 or 6 different LPKs. The biggest differences I have found is how smooth and polished they are, the quality of the finish, the consistency of the trigger pull, how "crunchy" the trigger is. I have not found any functional differences. I have tried a few different PSA, Anderson, Aero, DPMS, CMMG, Spikes and another one that was polished (or had some fancy finish).

I did have one lower, that required a set of anti-walk trigger pins added. Not sure if that was the LPK or the lower itself (it was a 9mm lower).
 

pooty

Member
Forum Supporter
#19
Have a new upper on the way so I want to cobble a new lower together. But I'm seeing so many differing prices in lower parts set its not funny.
Have built six or so lowers from the bargain bin parts kits (PSA and other online specials).
Received mag release that wouldn't catch the magazine fully, pivot pin that couldn't fit, trigger that couldn't recock.