Page 5 of 5 FirstFirst ... 345
Results 41 to 50 of 50

Thread: BCM Stripped Lowers

  1. #41
    Join Date
    Dec 2015
    Location
    NC
    Posts
    3,122
    Feedback Score
    50 (100%)
    Quote Originally Posted by 26 Inf View Post
    No, that's it. I haven't had any problems with them.

    ETA: I have an Aero M4E1 and like it just fine also - forged but looks kind of billet.
    Good to know. I prefer zero branding...
    If I order, I’d be curious if one of our gauging friends/members would do an assessment like that done of some others, including PSA.

  2. #42
    Join Date
    Jan 2011
    Location
    S.E. PA
    Posts
    1,700
    Feedback Score
    0
    My question is why do some of these top end manufactures who produce lowers that are supposed to be machined to mil spec wont drop certain pmags .....but all four Colts (The de facto mil spec) I have from 2009-2018 manufacture dates all drop everything. What specs are they using?? Are there paper specs that are tighter than what Colt actually uses?

    I picked up a LMT Defender and a MARS lower in the last two years and neither will drop Gen 2 Pmags
    "A flute without holes, is not a flute. A donut without a hole, is a Danish." - Ty Webb

  3. #43
    Join Date
    Feb 2011
    Posts
    610
    Feedback Score
    0
    Quote Originally Posted by OldState View Post
    My question is why do some of these top end manufactures who produce lowers that are supposed to be machined to mil spec wont drop certain pmags .....but all four Colts (The de facto mil spec) I have from 2009-2018 manufacture dates all drop everything. What specs are they using?? Are there paper specs that are tighter than what Colt actually uses?

    I picked up a LMT Defender and a MARS lower in the last two years and neither will drop Gen 2 Pmags
    There's someone in this very thread that had a Colt that was tight with PMAGs. I've also read in other threads where people said their Colts wouldn't drop PMAGs. So I wouldn't assume Colt uses any different spec.

  4. #44
    Join Date
    Oct 2014
    Posts
    928
    Feedback Score
    3 (100%)
    I had to go look through my old posts to find it but here's a thread where I shared about a brand new 6720 vs 6920 with apparently different final mag well specs. Dec 2017. I don't own either of those guns at this point.

    https://www.m4carbine.net/showthread...0-6920-quality

    Quote Originally Posted by grizzlyblake View Post
    The Gen3 20 rounder that came with the 6720 drops free just fine so I imagine getting some more Gen3s would be the solution to the issue.

    What I have a hard time with is that two brand new Colts, fresh out of the wrappers, have different final specs on the mag well interior dimensions - whether it's milling, anodizing, etc. I don't know.

    I don't see it as debatable because in the fresh 6920 the PMags are so loose they'll shoot themselves out if the rifle is held vertically and the mag release pushed. The exact same mags (brand new Gen2 PMags) have to be pulled with some force out of the 6720 when it's held perfectly parallel to the floor.

    So let's assume the PMags are out of spec. Even then, why would a half dozen PMags be loose in one lower and overly tight in another? Logic only says that the dimensions of the lowers are in fact different. Remove the PMags from the equation and pretend it's a piece of wood. Tight in one lower, loose in another; points to differences in lower specs.

    What I don't know is if Colt has a gradient of allowable measurements in these, and the 6920 measured out on the maximum spec while the 6720 measured out to the minimum, yet both passed QC. I'm just not familiar with the manufacturing.

  5. #45
    Join Date
    Jun 2012
    Posts
    2,815
    Feedback Score
    8 (100%)
    Not to further derail this thread, but it seems to be a Pmag problem rather than a receiver problem. I’m sure this has been discussed ad nauseum elsewhere.

    Just tested a Noveske Gen 2 lower, and Pmag Gen 3 does not drop free.

  6. #46
    Join Date
    Jan 2013
    Posts
    2,688
    Feedback Score
    40 (100%)
    Quote Originally Posted by scooter22 View Post
    Not to further derail this thread, but it seems to be a Pmag problem rather than a receiver problem. I’m sure this has been discussed ad nauseum elsewhere.

    Just tested a Noveske Gen 2 lower, and Pmag Gen 3 does not drop free.
    Its a QC issue. If the magwell is at or over .91 you're not going to have any issues. I have not seen a BCM with a drop free issue, their issue was with the pmag gen 3 over insertion tab bottoming out against the reciver.

    Noveske learned they had an issue with the Gen 2 and they fixed it. LMT, Colt, KAC ect.. the issue is they dont care about that spec (saying they go off metal GI mags) and you can get lower that are .90 to .92

  7. #47
    Join Date
    Aug 2017
    Location
    Lowcountry, SC.
    Posts
    6,174
    Feedback Score
    30 (100%)
    Quote Originally Posted by OldState View Post
    My question is why do some of these top end manufactures who produce lowers that are supposed to be machined to mil spec wont drop certain pmags .....but all four Colts (The de facto mil spec) I have from 2009-2018 manufacture dates all drop everything. What specs are they using?? Are there paper specs that are tighter than what Colt actually uses?

    I picked up a LMT Defender and a MARS lower in the last two years and neither will drop Gen 2 Pmags
    Dunno. Seems to be a mostly a boutique company issue. Usually brands that I have very high expectations of. Couple days ago, I took a G3 PMag, wrapped it in wet/dry sandpaper and crammed it into a *** stripped lower, no lube, like a hundred times. Still doesn’t drop PMags, and neither does my ***************. They both toss GI mags perfectly. I’ve got a few other brands that are tight, also.

    One, out of maybe 10 or 12, Aero strippers has been tight, but a few mag changes cleaned it up. Zev has the nicest magwells I’ve seen on any forged factory lower of any type, anywhere. I would assume that Mega’s, etc, are similar. Grey Ghost Precision also has a nice magwell.

    I’ve heard they exist, but I’ve never personally encountered a Colt that wouldn’t chuck a mag. To be fair, almost every Colt I’ve ever put to work has been reamed out by a series of enthusiastic 20yo kids for a decade plus. The 4 Centurion lowers I own are indistinguishable from Colts in any way I can detect, except the rollmarks.


    Edit: cleaned up because I don’t want to start any shit, particularly with individuals or companies I generally like.
    Last edited by 1168; 10-29-20 at 16:36.

  8. #48
    Join Date
    Jun 2007
    Location
    Washington, PA
    Posts
    90
    Feedback Score
    1 (100%)
    FWIW, I just picked one of these up yesterday, PMAG M3's fit perfectly. A little spendy, but a nice lower.

  9. #49
    Join Date
    Jan 2015
    Location
    MI
    Posts
    710
    Feedback Score
    0
    Sorry for the necro thread, I just wanted to add my recent experience to the thread.

    I was finally able to assemble the stripped BCM lower that I bought from the link in the OP this weekend.
    I bought a complete BCM® MK2 BFH 16" Mid Length (ENHANCED Light Weight) Upper Receiver Group w/ MCMR-15 Handguard to put on top, but wanted a stripped lower so I could add parts that fit my physical limitations and not have to throw away the stock parts.
    To be honest, you are paying for the name/roll marks on these is all.

    The mag well works fine on mine with 10, 20, 30 round PMags, but the upper lower fit is very sloppy (worst I've seen) with no way of adjusting fitment.
    I did not use any cheap/bargain parts, so I am a little disappointed with the build over all, but hey its just money, right?
    A BCM ambi charging handle would not work so it will be sent back to BCM as defective, I had a spare non ambi BCM in the parts bin and that one worked just fine..

    I also build an Aero M4E1 upper/lower this weekend for my wife and the Aero fits better/tighter than the BCM and has a couple threaded spots for screws to make installation easier, so the $100.00 difference in the two lowers is only for the name/roll marks.

    Like other have already said, unless you must have the roll marks, buy a cheaper lower.

  10. #50
    Join Date
    Dec 2009
    Posts
    717
    Feedback Score
    3 (100%)
    Quote Originally Posted by .45fan View Post
    Sorry for the necro thread, I just wanted to add my recent experience to the thread.

    I was finally able to assemble the stripped BCM lower that I bought from the link in the OP this weekend.
    I bought a complete BCM® MK2 BFH 16" Mid Length (ENHANCED Light Weight) Upper Receiver Group w/ MCMR-15 Handguard to put on top, but wanted a stripped lower so I could add parts that fit my physical limitations and not have to throw away the stock parts.
    To be honest, you are paying for the name/roll marks on these is all.

    The mag well works fine on mine with 10, 20, 30 round PMags, but the upper lower fit is very sloppy (worst I've seen) with no way of adjusting fitment.
    I did not use any cheap/bargain parts, so I am a little disappointed with the build over all, but hey its just money, right?
    A BCM ambi charging handle would not work so it will be sent back to BCM as defective, I had a spare non ambi BCM in the parts bin and that one worked just fine..

    I also build an Aero M4E1 upper/lower this weekend for my wife and the Aero fits better/tighter than the BCM and has a couple threaded spots for screws to make installation easier, so the $100.00 difference in the two lowers is only for the name/roll marks.

    Like other have already said, unless you must have the roll marks, buy a cheaper lower.
    agree, it's rollmark markup

Page 5 of 5 FirstFirst ... 345

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •