Pre-B magwell smithing info

[swilson]

Hi all,

have been searching for more detailed info from anyone that has opened up their pre B magwell to accept newer Mecgar 16rd mags.  I have exhausted the local supply physically checking to see if any would fit and did not find any.  My '89 is lonely with only one mag and the prices on the listed pre B mags is a little more than I want to pay to get 3-4 mags.

I am not looking to send the gun off to anyone to work on, but would rather try to do the work myself.  Am just trying to get a better starting point rather than trial and error with layout fluid and wear spots!

Anyone out there done this and willing to pass on tips???

thanks, Steve

[IvanSC]

I'm also interested in the answer to this question. What little info I found indicates that the shape of the leading/front edge of the magazines changed (got rounder, or squarer, I forget).

[swilson]

16rd 'B' Mags came in from CDNN today.  The mags would seat to within about 1/2" before they would stop.  I stripped it down to the frame so I wouldn't accidentally file the ejector block and started fitting.



 I was about to break out the dykem to mark everything and see what was binding, but with the grips off I could see first off that rear magwell opening part of the backstrap was causing the mag to tilt forward slightly the more I tried to seat it.  I filed with a needle file for a couple dozen strokes and VOILA!!! the mag would seat flush.



  When pushing the mag release though, I had to strip the mag out.  I then looked at the upper rear portion of the frame inside the magwell and filed on the entire flat portion that is just below the trigger bar.



 Reinserted the 'B' mag and hit the mag release and it dropped right out!!!  Cleaned everything and touched it up with a little bit of cold blue....reassembled and function tested. Everything works great.   If you are going to try this, go slow and test fit so you don't take too much off.

[Stuart]

Wow...that is awesome information.. thanks for doing all that..great to know this now.

[painter]

Does the original mag still work OK...not too loose in the magwell?

[swilson]

Doesn't move around at all.  The amount of material removed was very minor.

[painter]

Thanks.

[ruskiegunlover]

wait, is that ALL that is needed to do? Really? Is full dissassembly required to do this? Or just removal of the grips and slide, and the magazine well spring?

[wade-19]

Great info. I may try that. I may not though since SP-01 mags work just fine in my 86 Pre B.

[Saltydecimator]

wait, is that ALL that is needed to do? Really? Is full dissassembly required to do this? Or just removal of the grips and slide, and the magazine well spring?

bumping this cause he actually had pics...

basiclly ya need to do just like the pics show. remove fcg assy with ejector and file until the mags fit... pretty straight forward

[briang2ad]

WISH this was a post ten years ago!  (Before I refinished my PreB).

[Warpspasm]

Sweet. This is just what I was looking for.

[jurist]

Does any one who has done this have a pic of the side of the gun with the mag brake removed and grips removed. I'm interested to see how thin the metal is near the mag brake pin hole after this mod.

[SPO1SHADOW]

I have done this mod to many Pre-B guns. You don't remove enough material to make this area thin. There is plenty of meat left after the magazines are nice and loose. It does not take long to do this and you are only removing a few thousands of metal so there is no major change in either area that the small amount of metal is removed from.

[MBeach222]

Anyone have a smith do this?  Price paid?  Thanks