Lower receiver not mating

[iufan2010]

I finished building a spikes lower for my 300 blackout pistol. Everything went together smoothly and when I went to mate it with my upper, it is extremely tight. To the point of I have to use a punch to get the takedown pins out. The upper is a brand, MAS Defense, good upper, but that's for another thread. I've build a lower before and tried mating my MAS to that and it matched up perfectly. I took the upper off that one and put it on the Spikes and found the same problem so the culprit is definitely the lower. If it makes a difference, the parts kit in the spikes is a PSA kit.

I've tried oiling up the pins but every time it goes tight. The front pin seems to be alright, it's the back that is a pain in the butt. Any suggestions besides lightly filing the rear takedown hole on the lower because I would like to avoid that if possible. Thanks in advance!

 

[rvb]

I've had a few that were tight to the point of needing to tap the pins in/out... after a couple dozen times they loosened up to the point I could use my fingers. I consider it a good thing.

-rvb

 

[42769vette]

I've had a few that were tight to the point of needing to tap the pins out... after a couple dozen times they loosened up to be able to the point I could use my fingers. I consider it a good thing.

-rvb

x2

 

[midget]

I use one particular upper in all my builds to get the same results as what you describe. Less wiggle=less variance=more consistent. Do as RVB said and it should help, if not, you may have a burr in on of the holes.

 

[sig1473]

I've had a few that were tight to the point of needing to tap the pins out... after a couple dozen times they loosened up to the point I could use my fingers. I consider it a good thing.

-rvb

x3. My Noveske Gen2 N4 Lower was a tight fit on my Noveske MUR Upper. After having and shooting it for the past 6 months, I can finally loosen the pins with my fingers.

 

[iufan2010]

Alright. It's only seen about 60 rounds so far so I'll give it some time before I do anything with the parts. Thanks!

 

[Trigger Time]

Yep you have a good thing there! It will deffinately loosen up with afew hundred rounds. If it still bothers you then get some of the quick take down pins

 

[remauto1187]

+1 You want it tight! DO NOT go filing on anything! It will get better as you wear it in. The rear takedown pin is the only one that you will need to pull when you clean the rifle anyway. No need to pull the front unless you plan on putting another upper on it. This happens when you put 2 different brands together and can even happen with the same brand. It could be worse, you could have a set that mate together loose as a goose!

 

[IndyGunworks]

I've had a few that were tight to the point of needing to tap the pins in/out... after a couple dozen times they loosened up to the point I could use my fingers. I consider it a good thing.

-rvb

x4

 

[PGRChaplain]

Choot It! It'll come around!

 

[cosermann]

x5. Most likely you just got an upper and lower at the opposite ends of the tolerance range. Don't sweat it. It will wear in as others have suggested.