CZ75B Magazine Assembly Question

[OneWay]

   I recently ordered a few 16-round Mec-Gar magazines, 9mm. I pulled them apart to wipe down the excess packing oil.  The last step is sliding the metal bottom plate onto the base of the mag.  With the metal bottom plate pushed fully rearward, the locking plate (with the dimple) will not click up through the locking hole.  At this point the main lower magazine base can easily be removed, disabling the magazine.  If I give the bottom plate a whack on the front tab with a plastic hammer, the locking plate will fall into place.  I have to do this every time I assemble the magazines.  I've never had to assemble a magazine by whacking it with a hammer.  Does everyone have to do this to a 16-rounder?   
Thanks,
OneWay

[double-d]

I usually give the magazine a quick slap into the palm of my hand to seat the spring plate (base plate retainer). The more stubborn ones get slightly manipulated by a nylon pick.
Not just a Mec-Gar CZ issue, same applies to all semi-auto mags with removable base pads I strip.

I do the palm slap thing whether it is needed or not to insure all is locked in place.

[10-96]

When I was dept armorer, I took a small round grinding bit and hit the bottom of quite a few of our base plates back when we transitioned to Sigs.  Manufacturing left a bit of a kerf on the inside portion of the base plate hole.  It didn't take much, but it gave that dimple on the spring plate a place to get a running start.

[M1A4ME]

I've had to do that (smack the front of the magazine) with my hand, or a block of wood on plenty of M&P magazines.