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