View Full Version : Uber-tight upper:lower fit, how to loosen?
I have a Baer upper I want to use for a project. Since it's a Baer product, they of course have clung to their ridiculous "tight makes right" philosophy and I can barely get this upper onto a lower without a hammer, and taking it apart damn near requires a hydraulic press.
So, this begs the question, best way to loosen the fit? I'm obviously not a big tightness nut, but I also don't want it to get so sloppy that it induces feeding issues or rattles around like a cheap Pinto going over rumble strips. I want the pins hand-operable but not much beyond that.
What's the best way to go about this?
silviacrazed
08-25-11, 08:42
I would imagine light sanding or if you don't want to remove material, use a ball-peen hammer to slightly reshape the aluminum.
Sent from HTC EVO using taptalk
I understand that I probably need to open up the holes, but I'm looking for some feedback from someone that might have done it before. Specifically, tools/method, pivot hole vs. takedown (or both), etc.
Never had that issue. Usually the exact opposite.
Now for a few questions for you:
Is the upper tight to where you have no play at pin holes AND body(never got to play with a Baer).
Have you tried opening the holes and using makeshift pins(I know,I know you don't want to, just had to once. Don't ask).
Have you tried it on a known loose lower. Maybe it will work magic and solve both problems.
Rob, you have a metric shit ton more knowledge than I, just trying to give you what I can.
I've put this upper on every assembled lower I own (which is more than a few) and no joy on any. To be clear, the issue isn't one of wobble/no wobble, it's an issue of getting the pins to go in at all. I literally have to beat on them with a rubber mallet to get them in. The fact that it happens on every lower, and that I know Baer's ridiculous way they build everything over-tight, not to mention their shit customer service reputation, leads me to believe this is intentional on their part and is something I *should* be able to rectify at home and will probably have to.
I understand that I probably need to open up the holes, but I'm looking for some feedback from someone that might have done it before. Specifically, tools/method, pivot hole vs. takedown (or both), etc.
OK. Got ya.
Padded vice.
Number drill set.
Drill press or one hell of an eye and a hand drill.
Or round file.
ETA: just saw last post, damn that's just odd. Good luck brother. Sounds like your gonna have to either hit the hole or the body and remove material with a dremel or send it to someone.
Remove material till desired fit is achieved . That's the easiest I could tell you.
Failure2Stop
08-25-11, 09:36
I have had some very tight upper/lower fit rifles and carbines.
I made them acceptable with the following methods:
1- Slow. Completely strip pins and lugs of any lubrication. Using nylon punch, repeatedly insert and remove pins until do-able by hand while shaking assembled weapon.
2- Medium. Completely strip pins and lugs of any lubrication. Rub pin hole in upper lugs with Flitz or a bore paste. Cycle pins as above.
3- Fast. Be careful, if you make you upper looser than a Phillipino lady-boy, it ain't my fault. Be warned.
Take a new brass bore brush and chuck it into a variable speed hand-drill. Insert brush into takedown pin hole. Start slow, gradually increasing speed of the drill. Check fit frequently.
I would avoid drill bits and files.
Thomas M-4
08-25-11, 09:40
Use a old take down pin load it up with lapping compound and chuck it in a drill . Never tried it just an idea.
Yea basically what failer2stop posted along with the same precautions.
If you didn't know, the take-down pin hole in a Colt upper receiver is not round. It is in fact elongated. This ensures fitment/interchangeability. I would guess that take-down pin hole in the Baer is has just been reamed straight.
I certainly agree with F2S that any cutting tools should be kept away from the project. You might also try using the shank of a 1/4 drill or a spare take-down pin to lap the pin hole with some aluminum oxide lapping compound...
Took a bit to long and M-4 beat me to the line. :D
3- Fast. Be careful, if you make you upper looser than a Phillipino lady-boy, it ain't my fault. Be warned.
Almost fell off my chair laughing... :)
DirectDrive
08-25-11, 09:56
I have had some very tight upper/lower fit rifles and carbines.
I made them acceptable with the following methods:
1- Slow. Completely strip pins and lugs of any lubrication. Using nylon punch, repeatedly insert and remove pins until do-able by hand while shaking assembled weapon.
2- Medium. Completely strip pins and lugs of any lubrication. Rub pin hole in upper lugs with Flitz or a bore paste. Cycle pins as above.
3- Fast. Be careful, if you make you upper looser than a Phillipino lady-boy, it ain't my fault. Be warned.
Take a new brass bore brush and chuck it into a variable speed hand-drill. Insert brush into takedown pin hole. Start slow, gradually increasing speed of the drill. Check fit frequently.
I would avoid drill bits and files.
Use a old take down pin load it up with lapping compound and chuck it in a drill . Never tried it just an idea.
Yea basically what failer2stop posted along with the same precautions.
My thinking is in parallel with the above posts.
I might try using a set of those EZ-Pull Pins for tools along with bore paste/lapping compound combined with elbow grease (cycling).
If elbow grease was not enough I would chuck up some bar stock of the correct diameter in a cordless with bore paste and hit it with some slow, careful RPM.
I would try lightly sanding the pins with some crocus cloth and leave the holes alone. Crocus cloth comes in 3 grits and is used for fine finishing of metal parts. If you have any extra takedown pins laying around check them for fit, I have had some that were .001" undersize.
I guess I stand corrected. But I've yet to have dramatic overkill"ladyboy" looseness(that really is funny F2S). But I see how it could easily happen in the wrong hands.
I'm actually pretty sure that even with power tools I wouldn't screw this up.
This thing is INSANELY tight. I've seen tight before, but this is just bananas. I am not at all exaggerating when I say I have to beat on the pins to get them to seat, and I do mean beat.
The one thing I haven't done yet is test-fit loose pins to the holes to see how that goes. I can tell you that unlike some tight uppers I've dealt with in the past it doesn't matter which pin you drive in first, both are equally tight, which leads me to believe that both holes will need opening up.
I have dealt with this problem a couple of times. You don't need power tools. I have used both a small, round, fine file and and a wooden dowel with 150 grt sand paper.
Open up both holes a little at a time, frequently rechecking fit. My best guess is you will barely remove the anodizing inside the holes before you get the fit you want.
Hey Rob
As has been said, the front pivot pin hole should be round while the takedown is elongated front to back.
I'd work on the front first and use the shank of a 1/4" drill bit with lapping compound either by hand or chucked.
This one should be a precision fit.
Once that is set, move to the takedown.
If that is round it may need to be elongated with a file.
This hole does not need to be as pretty.
EzGoingKev
08-25-11, 11:28
IIRC there was a thread on TOS by a guy that had the same problem with a brand new rifle he bought from them.
He sent it back and they told him they fixed it and shipped it back to him. They ground/machined/filed the top of the lower and the guy was not happy with it.
If it's going to be used with a specific lower I'd try smaller pins before removing metal.
Are the pins in the upper tight by themselves or are they tight for the whole upper/lower assembly?
I take it you are using one of their flattop uppers without a forward assist? Correct?
If that is the case, another option would be to buy a Colt 750 LMG upper, remove the receiver, and sell off the rest. I know this isn't very likely but is another way to get what you want and their won't be any **** ups.
I need to test fit loose pins in the upper. I haven't done that. I've tried mounting the upper on every lower I have (several Colts, several BCM, an LMT, a Sully, and an old Bushmaster) and in all cases the pins have to be pounded in with a rubber mallet to get them in.
Yes, it's a Baer flattop non-FA. I'd love to have a 750 stripped upper but something tells me that would be cost-prohibitive.
Exiledviking
08-25-11, 12:57
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 need to test fit loose pins in the upper. I haven't done that. I've tried mounting the upper on every lower I have (several Colts, several BCM, an LMT, a Sully, and an old Bushmaster)
I am worried the holes are not lined up and this is causing a tight fit.
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 ****ing hate tinkering when I'm forced to just to get a product to work right. Blow it out your ass Les Baer mothergrabber!
I would try lightly sanding the pins with some crocus cloth and leave the holes alone. Crocus cloth comes in 3 grits and is used for fine finishing of metal parts. If you have any extra takedown pins laying around check them for fit, I have had some that were .001" undersize.
this is what I was gong to say. pins are cheaper than receivers...
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 ****ing hate tinkering when I'm forced to just to get a product to work right. Blow it out your ass Les Baer mothergrabber!
I'd say **** 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 un**** 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.
If the smaller pins are a bit loose in the lower, they'll cause wear in the holes of the lower.
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*$K their upper or give you a new one.
If the upper and lower fit and you are certain the gun will function correctly and safely, just shoot the shit out of it. I have had this issue, but not as bad, with some of my builds and they all seemed to have loosened up after a few hundred rounds.
Another option would be to send it back and tell them to un F*$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..
Is the rear lug hole an oval or round on the right side? They are suppose to be an oval.
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.
Already put the drill to it. I'd rather put the drill to my own head than call Baer. Those people make Pol Pot seem like customer service rep of the year.
I think I can sand down the lug a little bit and get it done. If not, recycle bin.
thopkins22
08-26-11, 17:51
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.
I think the consensus is that they will give him the runaround about tight being right etc....
ETA:Rob beat me to it....
Already put the drill to it. I'd rather put the drill to my own head than call Baer. Those people make Pol Pot seem like customer service rep of the year.
Is this something of a negative endorsement?:)
Is this something of a negative endorsement?:)
I get the impression that as an AR manufacturer, Baer makes a nice 1911.
My DD V3 middy's pivot lug is super tight on my S&W M&P lower & on my new PSA lower build. I need a mallet & wooden dowel to get it out. The rear lug is normal. I was hoping it would loosen up with use, but that ain't happening, so I may have to do something about it.
If only the lug was tight I might be able to live with it, which is where I'm trying to get this one to now. Provided it mates up, the pins go in/out easy, and I can rotate on the pivot pin, I'll make do with the rest.
I'm getting close to that now on one test stripped lower with lose pins. Dewalt > Baer. :sarcastic:
...Front, pivot, lug is 0.505" wide, rear is 0.50" wide.
Check the "Chinese Blueprint". Compare the lug dimensions to those on a lower you know works
I may be to late, but don't use power anything. The aluminum will cut very quick. I had one upper I built that was a bit tight. I was able to just use a .25" reamer (straight flute) to fix it. 320 grit sand paper wrapped around a 7/32" drill bit would work good to fine tune the hole. Also, you will never get an accurate ID measurement of a small hole using a caliper. You need pin gauges or a cheaper method is to use wire gauge drill bits, but they are not precision ground.
Jeremy
Yep, you're too late. And the drill worked great by all indications to this point. With as ridiculously tight as this thing was I would have been there for days with any sort of hand-power.
While I know I won't get an accurate ID, it's close enough for these purposes AND it's close enough to determine that the rear hole is round and not oval.
thopkins22
08-27-11, 08:17
Are you concerned with losing surface hardness?
Baer makes a nice 1911.
Thats up for debate.
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.
Pivot pin holes are suppose to be .248 at a minimum.
Are you concerned with losing surface hardness?
Not on this project.
This upper is something I want to use to test some theories on a new gun I'm assembling. I don't know that the final package will remain in it's currently-designed form but I want to get it together and get on the range and sort some things out with it.
I do this alot: assemble a rifle that I may not be sold on it's overall configuration as one of my personal go-to guns but that has a combination of parts I'm interested in trying together.
justin_247
08-27-11, 09:41
One thing I missed in this thread... how did you end up with the Les Baer upper in the first place?
One thing I missed in this thread... how did you end up with the Les Baer upper in the first place?
They sell an upper that has no forward assist. They are the only people that sell this currently by itself for builds.
http://www.lesbaer.com/223parts.html
This is the same upper that is used on the Colt LMG. Since the Colt LMG fires from an open bolt, a forward assist is not needed and can't be used anyway.
Stolen from Mongo's web page
http://home.comcast.net/~sfischer397/m16a2oblmg/m16a2oblmgpics/LSW3.jpg
justin_247
08-27-11, 09:56
Interesting!
I just discovered another option for this would be to find an older 9mm RRA flattop upper. The early ones were drilled for a standard gas tube and have a cam pin cuttout.
You would not have a brass deflector though. I doubt they would have M4 feedramps.
www.alumaloy.net never used it, but watched the infomercial some bored / drunken saturday night. Buy a couple of rods, a torch from lowes for about 30 bucks. Fill the lug holes on the upper, drill them out to correct size, a little cold blue. If it works as advertised you should be golden.
Thomas M-4
08-27-11, 17:43
www.alumaloy.net never used it, but watched the infomercial some bored / drunken saturday night. Buy a couple of rods, a torch from lowes for about 30 bucks. Fill the lug holes on the upper, drill them out to correct size, a little cold blue. If it works as advertised you should be golden.
I was talking to a buddy about that just a few days ago he had a coolant leak on a intake manifold. He ended up JB welding it :p
But reading robs posts it looks like the hole is pretty well in the correct spot but it is supposed to have a slight oval shape to the TDP but it looks as if LesBear reamed the hole to a true hole at the very minimalist of the spec maybe slightly smaller than spec.
Toyoland66
08-27-11, 19:35
From reading some other posts of yours I understand you are after weight savings by using this upper. How many ounces are we talking about?
No forward assist shaves 1+ oz.
(which is now where someone will wander in and blather on about "all of this for an ounce" or some other waste of typing)
Thats up for debate.
Not from me.
I've had a couple of idiot tight Baer 1911s.
Just don't see what they thought was so cool about a mainspring housing that had to punched out of the frame and then hammered back in.
I wouldn't be molesting any of my good lowers with that upper and a hammer. Fit the upper.
Thomas M-4
08-27-11, 20:53
I cant but help but to wonder if the Leas bear lowers would fit it better??
Or if it would be even tighter with the two of them together. :eek:
No forward assist shaves 1+ oz.
(which is now where someone will wander in and blather on about "all of this for an ounce" or some other waste of typing)
You will save even more weight by filing off the metal on the lugs...:jester:
ClearedHot
08-27-11, 22:58
My DD V3 middy's pivot lug is super tight on my S&W M&P lower & on my new PSA lower build. I need a mallet & wooden dowel to get it out. The rear lug is normal. I was hoping it would loosen up with use, but that ain't happening, so I may have to do something about it.
I have the same issue with a DD upper and a Bushmaster lower. The pivot pin will not go in unless I hit it with a mallet. Has anyone measured the diameter of the pivot pin hole on a DD upper and compared it with another upper like BCM, LMT, Colt, etc?
Make sure there isn't a burr on the pivot pin first, where the retaining pin slot is machined.
Quiet-Matt
08-28-11, 12:42
I purchased a used Del-Ton upper reciever for cheap off of the EE a while back. I used it to build a dedicated .22 for my son, on a Stag lower. I had fit issues, to the point that the takedown pin had to be hammered in while at the same time forcing the recievers together. It turned out that the problem wasn't the pin holes, but rather the milling of the recievers not mating up. It turned out that the Del-Ton upper was a fraction too long in the rear. I was able to remedy this with a emory board. I wasn't afraid to do this to this reciever because it to be used as a .22 only. In the attached picture you can see what little bit of material had to be removed, and now the two close up easily and with no slop.https://lh3.googleusercontent.com/-OOCCwiEDPCg/Tlp78TtzRUI/AAAAAAAAIyw/U4D8fdCMOlA/s1024/DSC02404.JPG
-Matt
----------
I know this will sound ghetto, but sometimes just using a standard drill bit close enough to the hole size will work too. I would try to do it by hand at first. Just manipulate it in and out and spin it in circle while rotating at the same time. Sit around and watch tv while taking your time. The hole will open up. If you need to go faster, use a drill at very low speed. But mount the drill to a table so it is solid. Its too easy to tip the drill and easier to maintain the proper plane with the lighter upper.
I know this is ghetto... but if you want to spend the cash, you could also bring it to a machine shop.
Rob,
I've had two LB uppers with the same exact problem. The pins were hammer tight on both regarless of the lower. What I used to open up the holes was labor intensive, but it worked. I erred on the side of caution and enlarged the holes by hand using, at first, 400 grit wet-dry paper rolled in a tube shape. Moving the sandpaper in and out while rolling the paper tube was effective, but took hours. For the second one, I started with 220 grit wrapped around a long roll pin punch as it was more rigid for sanding. I then moved to 300, 400, and finished with 600 grit and some polishing compound.
The takedown/pivot pins function normally on both now, but the odd thing is that I can't interchange them, i.e., when I do they're too damn tight on other lowers.
Yankeewhite
09-01-11, 22:19
Glad I'm not the lone ranger on this. I have a LB upper and I need a brass hammer to get it in the old pwa lower I'm using. I'm thinking now it is easier to use a RRA 9mm upper and have the tube hole drilled. Works great on all my lowers, even CAV lowers. No brass deflector hump either. I just can't go from slick side A1 uppers to flattops with crap on the side. This would be easier if I wouldn't have seen the the RDS light.:D
yallknowho
09-06-11, 01:41
I have a several year old noveske lower I finally got around to building up. the fit with it on my sr15 upper which I am using on it was horrifically tight. Rather than modify the receivers which are expensive pieces I just sanded down the rear takedown pin by hand with some 400 grit sand paper. it still fits pretty tight but the pin is easily removed using a round as a punch.
Failure2Stop
09-06-11, 14:20
Rob, I guess I'll go ahead and ask (as you have posted previously that you already solved the problem) what method you used and your general opinion of the method.
Tools, time, effectiveness, that kind of thing. After all, it isn't much of a help thread if the reader doesn't know who to trust and who to disregard.
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