Frankenstein lower with a BCM upper - issue with the selector switch

[pcauwels]

My boys and I recently completed two AR builds for them (their first AR's) and we are experiencing some issues with the selector functioning.

The lower may not be the best combination but most of the parts where purchased during the time of the AR scarcity...

Here are the parts used:
The lower receiver is a Doublestar forged receiver - had to do a little hand filing for the mag release opening on the receiver.

The lower parts kit was a no name kit from Del-Ton (LP1045) - had to do hand filing/custom fitting for the mag release as well

Everything else came together with the exception of an atrocious trigger and a more than mushy selector switch.

After a trigger job by a local AR gunsmith the trigger job was corrected and they both are now much better than my S&W AR15T.

The selector was still mushy on both however. They both move smartly from fire to safe but very mushy back from safe to fire.

I'm wondering if I should just go ahead and try to replace the parts.

Would replacing the selector switch, the selector spring, and the selector detent fix the issue?

I'm not sure if the parts kit from Del-ton are to blame, the Doublestar lower receiver, the installers (me and my boys), or some combination of the 3.

Anyways, any thoughts or previous experience with fixing a mushy selector switch would be great.
Thanks.

[the_fallguy]

My first build was a Del-Ton kit (the LPK with which I was told by the dealer was from DPMS). The selector switch was fairly rough until I filed some casting lines down that were left in the groove from the manufacturing process. That solved the issue temporarily until I replaced first selector with an ambidextrous version.

That original lower has since become my "ongoing experiment" testing receiver, with which I try out various stocks, grips, or other parts that I am curious about (right now I am playing with the Sully Stock). My "social" AR15 is constructed with a LPK from G&R tactical. Upon the initial assembly I found the function of the G&R kit was superior to the [hand finished and polished] kit from the Del-Ton build. Any of my future builds will utilize quality parts from now on.

[pcauwels]

It's a good lesson for me. I had 2 RRA LPK's that were on back order for over 2 months. Got sick of waiting and finally ordered the LPK from Del-ton.

I ended up buying a DPMS spring, detent, and selector switch (only parts in stock that I could get right away - maybe that should tell me something)
Installed them today without having to do any hand-fitting or polishing and the selection action is really crisp on both guns. I'm really pleased with the selector functioning now.

As far as the AR's themselves go, they both have around 1k through them with no failures of any kind (I think that is due to the full BCM uppers) and they are plenty accurate for our needs.

[GreyOps]

I had a similar experience with a Del-Ton LPK installed in a S&W M&P lower. I built it as a cheap back-up and had nothing but problems when running the gun hard. The first problem that surfaced was three and four round bursts that I traced to an out-of-spec disconnector, this was followed by a loose gas key at about the 400rnd mark. I contacted Del-Ton and was assigned an armory code and they requested that I send them the LPK. That was last June, I haven't heard from them since. I just recently ended up working on a friend's Del-Ton upper and BCG and I can say there is a very noticeable difference in quality when comparing the Del-Ton parts side-by-side with parts I received from G&R, LMT, Rainier, or Noveske.

[Belmont31R]

Stay away from no name and crap quality LPK's. In the grand scheme of things it doesn't cost hardly anything to get a quality kit.




For the price of a few mags worth of ammo you could have gotten a quality kit with some Colt parts added in, and had a rifle with parts that are not bargain basement.