That & more in my thread here:
Genesis: 4013 to 1013 to 1016
.
From what I've seen in my converted 4013 I'll disagree.
In post #9 of my thread above you'll see that without the magazine spacer the case is fully rearward & it's rim is subject to be behind the slide's breech face causing the first round to not be picked up sporadically when the slide release is depressed to chamber a round.
"Sometimes when you insert a new fully loaded magazine, with the slide locked back, & then press the slide stop lever down to pickup & load a round, it fails to pickup & load the top round.
What I noticed is that with the 1013 mag, because the spacer is removed, the top round sits fully to the rear of the mag.
With the slide locked back, when you insert a 1013 mag the rim of the top round hits the bottom the the slide's breech face. (Almost the full thickness of the case's rim is underneath the slide's breech face.)
Most times it pops forward of the breech face but sometimes it doesn't. When it doesn't it won't be picked up by the slide when you release the slide stop lever & you won't know it until you pull the trigger and are disappointed by the silence.
When a loaded 4013 mag is inserted the top round is well forward of the breech face, because of the spacer, & this problem doesn't happen.
The solution to the problem:
1)- always chamber the first/top round of the magazine by racking the slide by hand fully rearward (instead of dropping the slide stop lever on a locked back slide) as this allows the slide to go well past the top round's rim, and locked back point, and pick up a round every time,
or,
2)- slide the top round of a newly loaded magazine about 1/8" forward before inserting the magazine as this will allow the slide to reliably pickup the top round when releasing the locked slide.
"
.
.
Locked back slide position
.
