CMMG radial build, need extended baseplate for Magpul

[Les Snyder]

it looks like the bolt/magazine clearance problem I have with a CMMG radial bolt and barrel in my non factory lower has been solved by using Magpul 9mm Glock magazines... now problem is that they are 27 rounds, and would like to add an extension... have looked at T/F and TTI web sites and did not see a listing for extended magazine base plates specifically for the Magpul bodies... they are a different angle and my T/F do not fit... can anyone point me in the right direction?.... thank you Les   L747

[barrysuperhawk]

If someone can modify the taccom extension 3d model to fit pmags, found here:

https://taccom3g.com/taccom-3d-print-downloads/

and send the file to me, I will 3d print a couple for you for the cost of shipping (in a color I have).  Add a taccom spring kit and Bob's your uncle.

https://taccom3g.com/product/taccom-spring-kits/

I am not good enough at fusion360 to do it myself, and I don't have any 9mm pmag to test on.  In case you are wondering,  I am paying it forward because someone else helped me out. 

[Scooter]

I can modify the files if someone tells me what to change.

[Les Snyder]

Barry, Scooter thank you for the gracious offers of help....I have inquiries into Taylor Freelance and Taran Tactical....I really don't think I'm the only one that has encountered this problem with magazine clearance when using 9mm lowers by other than CMMG....I've shot the Magpul 17 rounders without a problem, and just received the 27s today... so far they appear to be a simple solution to the interference problem...I will try to get to the range tomorrow and test the longer magazines

 

the PMags have a "square" 90degree base plate similar to the Colt format magazines... a friend has a T/F for a Colt and I will check it out when I can, again, thank you for your offer of help, I'll keep your offer in mind... regards Les L747

[Scooter]

That's a pretty easy mod. I would need a few critical dimension just to verify.

[Dan Sierpina]

It looks like a coupler for the Magpul might be another option.

 

[MemphisMechanic]

11 hours ago, Les Snyder said:

I really don't think I'm the only one that has encountered this problem with magazine clearance when using 9mm lowers by other than CMMG.

 

You’re not. The rest of us elected to lower the magazine height in the gun, and we can use OEM Glock mags & extensions. Mag releases are cheap and easy to replace if you mess up.

 

I took roughly 1/8” off the top of the mag release in my KE Arms lower and it works great.

 

Edited August 9, 2019 by MemphisMechanic

[Cavy]

I watched a video from Cain arms showing a +5 base for magpul. Maybe they could make a longer one.

https://www.youtube.com/watch?v=hgl8bWC5o2Q

Also I think ZEV makes an extension that fits between the bottom of the mag body and the baseplate.

 

Edited August 9, 2019 by Cavy
additional info added.

[Les Snyder]

Memphis Mechanic...I first lowered the catch engagement in an ETS mag for my trial fitting... the bolt hit the front of the mag lip on the ETS and rear of the OEM Glock mag which was clearanced...  I milled the mag catch shelf on my NFA by .065" and the bolt would not strip a round, it contacted the top cartridge about 1/8" up the case.... I lowered the catch hole in a Colt style mag for the  lower for my SBR  with mag adapter for about .010" at a time and ran into the same problem on extracting the last round... what I am trying to accomplish is smooth hand cycling of dummy rounds...sharp point of the bolt catches the follower when the  last round is slowly extracted... the Magpul mags cycle dummies fine..most likely I would not have a problem with the magazine working in a match... the bolt would clearance itself over time....thanks for the comments, I too,thought lowering the mag catch shelf would solve my problems... didn't think a 1/16" would make that much difference

 

Cavy thank you for the heads up on the Cain arms

 

edit... ordered on the the Cain Arms mag extensions

 

thanks all... hope this works

Edited August 9, 2019 by Les Snyder

[Roy T]

Snyder I warned you about going down those dark rabbit holes

[Les Snyder]

received an e-mail reply from Robin Taylor (Taylor Freelance) ... said he may look into an extension for a Magpul....

 

MemphisMechanic.... what lower do you use?... my problem is most likely the angle of the mag well in the NFA lower as the Magpul follower  does not sit a high as as the ETS or Glock

 

Dan Serpina... thank you for the reply, that was an option I was considering

Edited August 9, 2019 by Les Snyder

[Les Snyder]

Roy... we have a new place to eat... the unit ran flawlessly with the Magpul 27 rounders today... I clocked the comp at a pretty severe angle... unfortunately my cataract does not allow me to use a dot sight... the ACOG is pretty sharp, so I'll use it

Edited August 9, 2019 by Les Snyder

[Dan Sierpina]

I'm following this, as I have the CMMG barrel and bolt group in hand. A Leadstar Arms upper and lower are at the FFL, waiting to be picked up. 

 

[Les Snyder]

Dan... good luck...I hope you have a drop in installation, or be able to provide clearance with a simple change in the mag catch shelf height... I may have been able to do so, but .065" was too much for my installation, and I encountered multiple angle and interference problems I really wanted a simple fix...I'm happy with the Magpul at this point, and even if the Cain addition does not proved enough rounds, I can always section a couple of the Magpul bodies... after all I started with a 7 round .45 in 1982, and can always stick a reload in

[Dan Sierpina]

Les,

   I started with the .45 in 1980, and still shoot Single Stack from time to time.  Messing with things is not new to me, I've been an R&D machinist for 45+ years, gunsmithed for a total of 12 years. Built guns for the Masters, including converting a Remington 572 to being box mag fed instead of the tube. 

Following some of you that already went down the RDB road will just make it easier, I think.