Thought you might be interested in seeing this. It was (I guess) done by the former owner of the one .45 that I'm working on.
Notice that it opens up the mag well a bit for faster magazine insertion but, does not add any parts to the frame.
The regular mag well is edge-beveled BUT, in addition the steel body of the mainspring housing has been radiused back & a beveled "half circle" cut into the grip frame metal. Then that cut needed to be carefully and slightly peened back to make close contact with the mainspring housing.
It opens the magazine well up about .25" (front to back) but, it is quite enough to make mag insertion nicely faster than the normal "stock" magazine well opening.
It's interesting modification that I've never seen done on any other Colt frame but this one.
It is a Series 70 frame BTW & I just recently bought a new/old stock Series 70 Slide for it on Ebay.