Lower Recievers Out of Spec

[Dragonback13]

FIRST...This is not a complaint about the transaction or about @THEIS in any way. I just want to give an update on the issues I have found (so far) with the lower receivers.

I purchased 10 of the lower recievers from @THEIS toward the end of October. He let all of us know that they were untested and not measured and to beware but the price was worth the chance.

Today I was bored and decided to build out one of the lowers and an upper kit I ordered a couple weeks ago. Like a moron I forgot to test fit the upper and lower before I started building them. Fast forward a couple of hours later and I have a completed upper and lower. I go to put them together for a function test and SHIT!!!!! The lug areas for both the front and rear takedown pins are too narrow for the lugs to go in much less seat.

SORRY I FORGOT TO TAKE THE BEFORE PHOTOS

 

[Dragonback13]

I tested all 10 that I ordered and all of them are too narrow. I contacted @THEIS and he was very helpful. It appears some of them fit just fine and some are too narrow just like the lot I ended up with.

I found that the left side of the pivot pin reciever had not been milled down to spec but the right side was correct. That was an easy fix and only required milling a bit off that side. I then milled a few thousandths off both sides of the receiver and that solved the fit problems. Fortunately, I have access to a milling machine at work and was able to fix those issues.

Move to the newly discovered issue. The magazine well is too tight to fit a GenM3 PMAG but will fit a standard metal magazine. However, the metal magazines are not activating the bolt holdopen. I haven't had time to mess with it more but will see if I can find a solution short of milling out the mag wells which I have no interest in doing.

Any ideas are much appreciated.

 

[THEIS]

Hi,

Thanks for posting your information as it may help others for sure.

@Spblademaker
Did you have to do anything with the original lowers to get magazines to hold bolt open?

Sincerely,
Theis

 

[Dragonback13]

Hi,

Thanks for posting your information as it may help others for sure.

@Spblademaker
Did you have to do anything with the original lowers to get magazines to hold bolt open?

Sincerely,
Theis

No problem. The milling wasn't too bad but this mag well issue is another monster on it's own.

 

[Dragonback13]

UPDATE:
After some more jacking with the lowers. I went ahead and built out a couple more of them for testing purposes. I have found that the bolt catch will work with the metal mags. The one that is not functioning feels like there is a bit of drag or a stiffer spring in the bolt catch mechanism. I will disassemble that part and reassess it.
I built a matching set and will go out and test them today. The optics are super cheap red dots that I had laying around but they will work for testing. Everything seems to be working fine so far.

 

[Dragonback13]

I took both rifles out for testing and had nothing but issues.

If I cycle the bolt manually it picks up the round just fine and most often will cycle the first round and fire the second. After that, it is a combination of failure to strip the round out of the magazine at all or stripping it and setting it at almost a 90degree angle missing the chamber completely. This happened with both of the 20 round mags I was using.

I plan to try a couple of new mags and a couple of 30 round mags also. I will also give a very thorough cleaning and run both guns very wet this time to see if that helps. I am going to check the gas systems as well but can't believe would be gas system issues with both guns.
Any suggestions are greatly appreciated.

 

[corey4]

What brand are the components?

 

[Dragonback13]

What brand are the components?

Mostly relatively inexpensive components.
The lowers are GAADM, LLC and were sold "condition unknown" by @THEIS as described above. They have been milled to fit the uppers but nothing else so far.
Davidson Defense upper
Davidson Defense BCG
Mercury Precision 16.5" barrel w/midlength gas system
3oz buffer and standard buffer spring

 

[Dragonback13]

UPDATE:
I did a full breakdown and cleaning of both guns and reassembled the lowers. After disassembling both of the uppers and BCGs I cleaned them really well. I also removed both gas blocks and gas tubes. Cleaned them and ensured full airflow through all parts. I also ran a drill bit through the gas port on the barrel to ensure there was no blockage.
As I reassembled the gas systems I realized that the blocks may have initially been slightly misaligned. I put everything back together leaving the upper and BCG really wet to ensure that friction wasn't the issue.
I took them out and both guns ran flawlessly. Good solid ejection, loaded all rounds from the magazines and locked open on the last round.

 

[Dragonback13]

The only thing to figure out now is if it is possible to make the lowers PMAG compatible. I am not big on milling the magwells but may try it on one of them. Otherwise, I will just run the metal mags instead.

 

[_Windrider_]

FWIW I have the same issue. Again no complaints about them or @THEIS. I just haven’t gotten around to doing any mill work yet. I bought these to make backup guns to pass out to neighbors when the shit hits the fun or just beat the shit out of.

 

[Dragonback13]

Honestly, I am fortunate to have access to a milling machine and the milling was easy but the maxwell issue kinda sucks.
Just be aware that only the inside of the left side front post that holdsthe pivot pin need to be milled. But, both sides need to be milled in the rear takedown pin area. The rear area could easily be done using an 80% lower jig and the front post could be done with a flat file as a last resort.

 

[Dragonback13]

I am thinking that I may can solve the magazine issue using a file easier than trying to get all the way through with the milling machine.

 

[Dragonback13]

I also thought, just for fun, about milling one similar to this and see how it turnes out.