I thought I'd let everyone know that I finally got to the final round of abusing my sacrificial Tapco '47 magazine.
As I stated I would, I took the magazine internals out, laid it on it's side and pounded it with a rubber mallet.
In my previous test, I tried to shear off the locking lugs of the magazine while it was still locked into my rifle with no success.
I once again took the rubber mallet to the magazine starting at the bottom of the magazine, then to the center and finally to the top.
The bottom and center of the magazine sustained 30 heavy and rapid blows with no deformities resulting.
However, the top, where the feed lip would be, took 5 heavy rapid blows before splitting down the side of the magazine about 2 inches from the top of the magazine and running down.
A bit of the cracked portion was wedged into the inside of the magazine, which I was able to pop back into place after some considerable effort.
I replaced the magazines internals with no difficulty or complications and loaded it up to capacity.
I then manually cycled 30 rounds through the rifle with zero problems.
The magazine still locks into place solidly and drops free without any coaxing.
Per my specifications, the Tapco magazines suffice.
I am curious now as to how their 74' magazines would hold up to a drop test, repeatedly being dropped onto in the prone position serving as a monopod and unrestrained pummeling until the first sign of structural compromise.
I do apologize for getting back to anyone who was interested in how this all progressed in a late manner.
I've been going to school to become an EMT and I've been doing fire station rotations for clinicals in addition to studying for finals and the National Registry.
I've got the finals taken care of, I have one last clinical to do in an ER and I have the Registry coming up.
If anyone has any questions about the magazines or would like to see pictures, PM me and I'll get back to you.