After checking with other people who know more about guns than me and confirming there is no decent way to mate the Spike’s Tactical Lower with the Kaw Valley Precision upper, I have decided to get rid of the lower, get a Glock magazine adapter for regular AR lowers which I know mate well with the KVP. The other option would be an even swap for a PSA dedicated lower locally as I need to make 100% sure they do mate properly even though I keep getting assured over a stack of bibles they do indeed match.
And if I get any more annoyed, I will be willing to trade the whole shit for the shortest complete and reliable 5.56 upper.
A Ruger Charger in 9mm will also be very acceptable. And I have the nagging suspicion I should have gone this way from the beginning but wanted something super light for the missus.
One thing is for sure: This is my last AR-9 build. At least till they get their shit together and standardize the whole platform
Get her an M&P FPC. My friend’s wife loved mine when she got to shoot it.
You hit the nail on the head with platform standardization. I treat the 9mm/PCC ARs just like Large Frame ARs, eith everything comes from the same manufacturer, comes from a vendor/mfg that knows the compatibility for a fact, or is treated as incompatible until proven compatible.
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Even then, I’ve seen so many stories like yours about people trying to get PCC ARs to run correctly that I don’t even want to mess with them. I’d much prefer going to a platform that was built from the ground up as an SMG/PCC like a Scorpion, MPX, HK clone, Colt 635, or even the PSA AK-V/some other Vityaz clone. The Ruger PC Carbine, Henry Homesteader, Marlin Camp Carbines, and similar are great as well, I just like double stack/double feed magazines for PCC/SMG guns.
I’m reminded of computer scientist Dave Clark (Harvard or MIT, I forget) commenting that “the nice thing about standards is that you have so many to choose from”.
Lack of interoperability is, unfortunately, all too common with standards across many disciplines. Not many writers understand that “conformance should imply interoperability” — and it requires hard work to make it so. In some cases, writers may even tell you that “conformance implies interoperability” is a non-goal for them. Unfortunately, they don’t necessarily lose “the pen” as punishment for that nonsense.
Check out on YouTube for Hops channel( a Firearms Blog TV contributors personal channel) and his video ‘The Perpetual Agony of the AR9’ where he also commiserates about the lack of compatibility.
But, no, there is never gonna be a ‘standard’ for pistol mag compatible AR9s, because it’s all trying to fit a square peg in a round hole and they all suck so everybody is trying to find the better mousetrap.
The closest to a AR in 9mm standard is gonna be the classic Colt solution, because it actually was made for, and had contracts, but then you are stuck with Colt pattern stick mags( which is a good thing, the only place Glock mags are good is in Glocks).
Outside of that, the new S&W PCC is an AR style( but it’s actually an embiggened M&P15-22) that can take Glock mags and you don’t have to worry about parts compatibility because you can only buy the complete gun.
I have two PCC 9mm builds. One is all Aero Precision with Faxon 8.5″ barrel and the other has an Aero Precision Upper and a Brigade Lower (because I could not wait indefinitely for an Aero Precision lower during covid) with a 10.5″ Faxon barrel. Both take Glock mags and both work flawlessly after many thousands of rounds. I have no problems with Pro-Mag industries 50 rd. drums and could not be more satisfied. They both run all day with +P+ rounds without malfunctions.