80% problems

[Cummins_Powered]

I saw the front take down pin and laughed my ***** off, sorry, just looked so wrong. what I would do is dermal down the takedown pin it's self so it sits flush with the lower, the bolt catch should be abled to be hammered out and redrilled as well. Good luck

Wanna laugh even more? look closely at the bolt catch pin....its blind pinned. no way to tap it out.......

I'm wondering if it was the cerakote that added a small layer of material to make everything fit too tight. Most 80% lowers I've worked with needed a little persuasion to work right. Not quite as bad as you have it but small issues.

I thought maybe...but its not the case i dont believe. all my problems i think are due to poor roll pin/detent spring holes. They are all either drilled off center/angled/or off of where they should be by 1/16" of an inch or so.

[ElvenSoul]

Try EP Polymer Lower....hear there easy to do

[Cummins_Powered]

Well here is the damage....


I think that the slot (that surrounds the spring) for the bolt catch is not drilled deep enough...

[umd]

For #3 I had that problem when the hole through the bolt catch was too small. The bolt catch should rotate freely around the pin.

[badicedog]

my 80% lower. (I milled it to 100% already)

There are a number of problems, all due to things that were already completed on the 80%. I am trying to figure out if these are problems people have heard of.

First off, Has ANYONE had any problems with any aspect of the lower parts kits installed in their (or have firsthand experience) 80% lowers?

Problem 1: Magpul moe grip left a big gap between the front of the grip and rear of the trigger guard. Used a different grip and it seems fine now...

Problem 2: fire selector switch is slightly off, meaning it doesn't travel from vertical to horizontal but rather slightly past vertical to slightly less than horizontal. My guess is the detent hole is not drilled 90* to the selector hole but at a slight angle. Poor machining?

Problem 3: The biggest issue. The bolt catch doesnt move at all. as in once i pinned it into the lower, it is pinned so tightly against the lower that it is jammed in place. basically it would not function at all once the final round is shot. Again i think the hole for the roll pin was not drilled in the proper location.

Problem 4: front takedown pin. again we have an issue with the dentent hole being off center. It should be drilled in the "center" and at a 90* angle to the takedown pin hole. but it is slightly off, causing the pin to sit at an angle. which in turn does not allow it to fully pin the upper and lower together.


So did i just get the biggest POS 80% lower ever? are manufacturing problems like this common? The quality compared to my spikes lower is absolutely horrendous.

Ok, first off... Welcome to the homebuilt firearms 80% lower world!
You must also understand that homebuilt firearms are NOT 100% functional like their industrial counterparts. They require minor and sometimes major gunsmithing/fitting. You have to file a little here, sand a little there... Get my point? But hey it's the fun of it.. Some will fit better then others. Your second or third build will be better, you'll see

[badicedog]

These two photos show the front takedown...hopefully what i was saying makes more sense now.





Here is the bolt catch/release. The problem now is that i pinned it in place. and it cannot be tapped completely through to remove it. I guess it would have to be drilled out.




As you can see the lower was cerakoted. which is rather thick. i filed down the areas where the fire control pins and take down pins sit. i didnt touch the bolt realease hole. which may have been a huge mistake.

why can't it be tapped out? Just use a clamp or vise to secure the lower and carefully tap it out. As for the mag release, you have to use a jewelers file and carefully remove material from the top and bottom areas where the mag release lever sits. I had a similar problem with the bolt catch, I also used a small jewelers file to remove material from the are where the bolt catch rests. Good luck and tell us how your next build turns out.

[baih777]

why can't it be tapped out? Just use a clamp or vise to secure the lower and carefully tap it out. As for the mag release, you have to use a jewelers file and carefully remove material from the top and bottom areas where the mag release lever sits. I had a similar problem with the bolt catch, I also used a small jewelers file to remove material from the are where the bolt catch rests. Good luck and tell us how your next build turns out.

he cant tap it out. its a blind hole.
you could fix the front pivot pin hole with a mill.
you have yourself a real paperweight.

[kurac]

that bolt catch/release won't pivot because the hole for the pin that holds it was drilled way to low. You will have to grind the bolt catch and make the slot it fits I bigger or a little of both.

This thread was educational for me, if I ever buy an 80% I will know of a couple more things to look for.

[autoduel]

It's not the detent that's drilled off center. It's the hole for the pin.
Will the pin even go all the way through with an upper attached? It's clearly not square.

[tanakasan]

It is off to the high side so the upper will *probably* go on but with a big gap. Or the CTC distance will be off and it will be hard/impossible to pin at all.

Robert

[klewan]

Having a functional 100% lower to compare against the 80%; priceless...I have a couple of TM's coming, the measuring tools will be out and used...

[Palmaris]

Seems like pretty common for billet lowers. I've seen these problem more then couple of times.
STAY AWAY FROM NON-BRANDED BILLET LOWERS!!!

[SlickmisterN]

I would demand my money back, that is truly atrocious machine work. The front pivot pin takes the cake, I've never seen one so far out of spec. None of the issues you've described are common with quality 80%ers.

Tell them to put it back in the scrap pile as it would take more time, money and effort to fix it properly than its worth at this point.

[tanakasan]

^^Yup!

Even my Rohg lowers were WAY better than that! Too bad OP has a lot of blood, sweat and tears into it so far. I believe they cannot just take it back as it is now a firearm. At least try and get a refund.

Robert

[tal3nt]

I have the selector timing issue on one. I think the detent hole was drilled slightly too close to the trigger guard. Only off by a few degrees and works reliably though