Am I the only one that opens boxes like this:

This is using the stock mag bodies that came with the SP-01. the rear cut of that mag is flat across and more tapered to a point on the mag body. I have 2 of these mags.
24 rounds with this setup . last round is tight. Will most likely download by 1. 21 rounds of the open major rounds. weird.
I also have 2 mecgar 17 rnd mags that are a little differently shaped on the mag body. the cutout is a semicircle on these mags and they have blue followers.
23 rounds will fit in these mags. These mags seem better made, and I prefer them as far as fit and fee., but the triangle design seemed to allow for 1 more round. The last one on this mag is not quite as tight so I'll try 23 on it. 23 rounds of the open major rounds. advantage. There is also some writing in the mag springs that state use with certain type of mags.
You can see the ext. mag springs and followers on the right. These go in with no floorplate in the mag base.
This initial testing is with the minor PF rounds which are standard COAL (I forget ATM).
Dry cycling rounds seems GTG. well see how she runs on the range. They were about $58 each for the upgrades from Ben Stoger pro shop (great folks).