I appreciate the info in this thread. I have a similar problem, except that the tight component in my case is the lower. I’m gonna check my take down pins and see if I have any that are smaller than the pair I was using.
If it were me, I would consider altering the take down pins (vis a vis) some real fine cloth before I would do anything to the receiver. Especially because they are known to loosen over time.
My Vltor upper is very tight to my Noveske lower. The takedown pin really hasn’t been an issue, but I couldn’t get the pivot pin out w/o some type of pin punch doodad. Typically, I would use a dummy round and something to smack it with. It was equally tight going in.
All that being said, I tried another set of pins I had lying around and it got a little better.
Over the course of using the rifle, cleaning etc, they fit perfectly. Just a few cycles of taking the pivot pin in and out worked. Now I can push them out with just a dummy round, no smacking.
My suggestion would be to work on the pins, not the receiver. You can always touch them up with a little cold blue if needed.
I am worried the holes are not lined up and this is causing a tight fit.
I wonder if this might be the case.
Do you have a stripped lower to see if the holes line up correctly and if so, how much media might actually be blocking the pins from going through?
Update.
Tried Just the pins in the upper without the lower and while tight they were nowhere near as tight as when assembling with a lower. Put the upper on 6 different stripped lowers and the front lug for the pivot pin was too wide for ALL OF THEM. Couldn’t even get it seated on the lowers far enough to get the pin in. Had to start with the upper rotated forward just to get the pin started and then closed the two halves to get the takrledown pin in. Couldn’t get either pin in all the way with just my hands but in spite of pushing them in by hand had to pound them out once in.
I fucking hate tinkering when I’m forced to just to get a product to work right. Blow it out your ass Les Baer mothergrabber!
this is what I was gong to say. pins are cheaper than receivers…
I’d say fuck it with this upper. All you are going to do is egg out the pin holes on your nice lowers. Its either that or start sanding down the takedown lugs. Since they are oversized also.
I know it would be nice to have a kiss upper like this with no FA and I have been thinking about a build like this myself, but I can bring myself to buy anything LB.
I’m waiting for KAC to come out with their PDW uppers with no FA or brass deflector.
Les Baer is a douche.
Unfortunately this does seem like a lost cause. But since the money is spent already I may as well mess with the upper and see if I can unfuck it.
If the smaller pins are a bit loose in the lower, they’ll cause wear in the holes of the lower. Before lapping the holes of the upper, trim the lugs so they fit right. After getting the lugs fitted and making sure the holes of the upper line up with the holes of the lower, lap just the holes in the upper.
The methods FTS suggested for lapping will work
The rear lug appears to be ok and fit right.
My guess with all of this is that this entire batch of stupid is intentional on the part of the idiots at Baer.
I don’t want to use smaller pins, mod the pins, or anything else. The upper is the problem, the upper needs to be fixed or be trashed. I’ll make attempts to reduce the size of the front lug first and go from there. I’m going to measure it and measure a bunch of other lugs to get an idea of how much is involved. Once that’s resolved I’ll look to the pin holes.
Yes this is true.
Steel takedown pins always win when matched up against aluminum. The upper and lower eventually loosen.
I’d ditch that upper, but slamming the upper and lower together with the front pivot pin in place a few times has been known to fix this issue. This was recommended by VLTOR when I was having a MUR fit issue.
If the upper and lower fit and you are certain the gun will function correctly and safely, just shoot the shit out of it. I have had this issue, but not as bad, with some of my builds and they all seemed to have loosened up after a few hundred rounds.
Another option would be to send it back and tell them to un F*$K their upper or give you a new one.
All that does is put more wear on the in-spec parts at a faster rate.
I would modify the upper by hand.
Is the rear lug hole an oval or round on the right side? They are suppose to be an oval.
Rob,
Drive the pins in and out enough to see where the contact/ wear point is on the lug of the upper. Work it with a small file, or dremel if you need to work quicker and are sure of your mad skills. You already know to check it often and leave it a little tight so it will wear in.
I’ve had to do this on one upper that was so bad I had to use a steel punch to get the pin in and out.
My new PSA upper is still TIGHT on the rear pin on my DPMS ‘factory’ lower… I use an allen-key to align (from opposing side) and tap lightly in with a jeweler weight hammer to get it in…
Of course I think its slowly working IN… I’ve only cleaned it like 6 times in 1000 rounds… (or 4 range trips)
I like the tight fit… which I hear is better… but if you got to BEAT them in all the time… thats an issue… a dowel with 220 grit may be your best friend… IMHO…
No, it is round. Finally just got the calipers on it. It’s .245" ID.
Interestingly the pin fits tighter in the rear hole but the front lug is the fat one. Pivot pin hole is .248" ID.
FWIW, in most lowers I’ve now tried this in I cannot even pound the pins in without a rubber mallet, so this is nowhere near normal tight.
Front, pivot, lug is 0.505" wide, rear is 0.50" wide.
Rob
Have you tried contacting Baer? Maybe they can exchange it for another one. I had an upper receiver from BCM that was uber tight as well. It was tight on Colt, LMT, and my Noveske lower. I emailed Paul and he exchanged without question. Got a new one and I drove on. Just a thought.