I'm in the process of SBRing my rifle and one of the things that I've been hung up on is whether I should SBR my PSA lower, or if I should go with something else -- a LW billet lower for an example, for a little weight savings, but also for a tensioning screw. If I'm going to have this gun for the rest of my life(presumably), I want it to feel like a single piece, rather than an upper and a lower held together with a couple of pins. I know that the receiver wobble isn't an issue in functionality, and it's not even something I notice while shooting, it's just something I notice whenever I'm messing with my muzzle device or taking things off of my rail, etc.

I've looked at some options about removing the wobble, the accu-wedge(tried it, hated it), O-rings, even those incremental spacers, but I found some manufacturer making oversized pins that are supposedly .001" thicker than standard pins. That got me thinking... I'm planning on having my rifle cerakoted, and if it's done professionally, it should add a mil or so of thickness to the parts anyway. In that case, I could potentially buy the pins I wanted to buy(standard sized, lightweight options) and with the cerakoted receivers, the gun should fit tighter overall.

Is this correct? For the guys who've had their AR-15s cerakoted, what conclusions have you come to about the fit of the upper and lower? If you had a loose fit beforehand, was it tight enough to remove the wobble but still loose enough that you could remove the pins by hand? If the fitment was tight before the cerakote job, I'm going to assume that it would be to the point where you might have removed the cerakote inside the pin holes.

Doesn't matter what you do, the gun will loosen up with use.

I don't know if Bill Springfield's Trigger work is good or not. But he will put Tension Screw in any lower that you want. There are internet reviews saying he's great & people saying it's not good but he always offers & try's to fix what ever the problems people had. I was looking at his website because he does Walther P99 triggers which nobody does. I bought a Barnes Precision Machine NP3 Lower that has tension screw but later found out Aero makes BPM Receivers. I also bought Area 53 lowers that have tension screw's & Trigger Adjustment screw in there lowers.

AR-15 Upper/lower receiver tightening $35.00

I can tighten up the fitting of  the upper/lower AR-15 receivers by installing a set screw that engages against the upper receivers retaining pin boss. The set screw can be accessed by removing the pistol grip. To adjust put a drop of Locktite on the threads, turn the set screw until the upper receiver movement is minimized. Check to see if the lower receiver pin can still be able to move with finger pressure. If necessary back the set screw off slightly until the pin can freely travel. This procedure can eliminate up to 95% of upper/lower movement.

This modification is not visible when the rifle is buttoned up. Price is $25 with trigger work or $35 with out.


Priority Mail return shipping is included in the price!

When I recently did the spray can route with Aluma Hyde it mostly certainly tightened things up, so I would suspect that Cerakote would too but in the end it will all wear and eventually go back to where it was with a slight wobble.

Oh my god, this is actually what I was looking for originally. I couldn't find anything when I went to Google so I was trying to figure out some other fix. Thank you for this, definitely bookmarking it.

And to everyone else, yeah, I know that friction will cause the coating to wear. I was wondering if there was some kind of sweet spot where enough of the coating has worn off that no more will be lost from pushing the pins in and out, but that the fitment would still be tight. I thought of it almost like getting a matching upper and lower from a manufacturer where the pins are tight fitting, sure, but they aren't tight enough to cause unnecessary friction.

I wouldn't send anything to Bill.   Google his work

Drilling & Tapping Aluminium for tension screw is hard to mess up unless it is not located under takedown pin. I would send email to ask if the work is done with end mill or drill press.

Trigger work? Archived Thread.

https://www.ar15.com/forums/t_3_118/699319_Who_can_drill__tap__and_install_a_rear_tension_screw_in_my_lower_receiver_.html

You being in GA, I would see if Rudy can do it. Hes on here as Mad-Machinist. Or you can google Macon armory and contact him that way. He would be the guy I would have in mind for this project.

Macon Armory

I found another Gunsmith but the price is almost 3 times more.

Scotts Gunsmithing Services


*Tighten Upper to Lower Receiver Fit $95.00 Labor
Service includes drilling and tapping the Lower Receiver for an adjustable set screw to add upward tension on the Upper Receiver to minimize Movement/Play. This Modification WILL NOT eliminate Front Receiver Pivot Area Slop/Play.

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Barnes Precision Machine

We install this feature(like other premium grade lowers have) to tighten up feel from upper to lower when assembling.Those who know better ,(and most consumers ,with all due respect ,do not)realize Uppers are made within a tolerance range and so are Lowers ...and because of this tolerancing of parts you can get an "in tolerance" machined upper or lower ...and get more play than the ones assembled yesterday...that were also well within tolerances ..IT IS tHE NATURE OF THE DESIGN!!!!!!!!!!!!!Those who say a little play is an indicator of poor /unacceptable quality ,do not understand the way the weapon works ...or how Eugene Stoner designed it /meant for it to be made.Ever heard of an ACCUWEDGE????? Why do they exist????? Because issue has been around for many years ,and they( Accuwedge) had the first commercially available product to address it .I have seen Colts (the worst) Bushmasters/DPMS/Olympics/LMT's /Stag/Rock River/ as well as a lot of no names ...and they ALL exhibited a certain amount of play/looseness. Ours are no better/no worse....because we machine to the SAME TOLERANCES.That is also why some of these very folks tell us we machine a GOOD QUALITY/IN SPEC product that is indicative of common industry players.
If you shoot a high mag scope ...reducing upper to lower play might help tighten up groups because of less wiggle of upper once on target .(your heartbeat/breathing can affect reticle movement in this situation) ...and so can loose fitting upper to lower....it can effect group size , but it is not a "direct" effect as mentioned .
Weapon will exhibit a looser feeling the more rounds you put through it ,the more you disassemble it to clean it...and this screw gives you the option of tightening it up during the life of product.It is an old USAMTU (US Army Marksmanship Training Unit )trick that gunsmiths/armorers have been doing for YEARS....but no one until the last few years ,has been including it on production models.It is a method taught by most gunsmithing /armorers courses,as well as other "steel bed" methods,as taught by Mark Hunt at Montgomery Community College.
I did not come up with the idea ....we just decided to include it as a standard feature in our lowers ...along with hole for detent pin/spring for rear takedown pin being tapped for a set screw ...so you can do stock changes with out losing /dealing with detent pin/spring.These are just two of the things that make ours a Premium grade lower receiver in many peoples eyes...and since we do not machine uppers ....yet- it gives our customers the option of mating with ANY upper in industry ,while maintaining a tight fit.
Thanks for listening.

In most instances , this is not an "accurizer"..... but it can be of benefit in a DMR (Designated Marksman Rifle ) with high magnification scope -where you want instant /accurate feedback from manipulation of the pistol grip to align crosshairs ( especially extra fine crosshairs on target/varmint scopes ).

We believe tightening up fit between upper to lower can help in this instance ....and 1-1/4 " dia groups at 325 yds from ANY semi auto gas gun aint to shabby ..and should be the kind of shooting where it is most helpful....and that is only partial feedback from folks here at CSF, as well as other target/varmint/precision type shooters .

When "Premium AR rifle builders " (sic) take the time and labor intensive effort to ream front /rear takedown pins to final dimension at assembly- all it takes is breaking down the weapon several times to get wear induced into these holes ( as well as shooting it ) and then you dont have the tight fit anymore ...the more you shoot it , the more you clean it /dissassemble it ...the more it wears in these areas ,and then it is not as tight as it once was .
Story of our lives right ???LOL!
Our feature allows adjustment for the life of the assembly.

As you will see by the scores at DRPC this season , our shooters ,as well as others- dont have any issue with tension/fit .... they dont even bother to tighten them up.....most of them do not even use the screw.

We now machine a custom screw for this application -as ones off the shelf we used in the beginning just do not hold up.....
anyone who has purchased a BPM lower that needs one -please notify us ,and we will ship you one at no charge .

We include part in our parts kits if requested .
Some folks use our parts kits for other lowers , so we do not include in every kit , unless requested ...at no addition al charge .

New design has much larger " head " to put pressure agaisnst pin boss on upper receiver.....
plastic tip on storebought screws tends to flatten out over time .
New design of screw /head totally eliminates this.


Andrew @ BPM

Here ya go