Im no 1911 expert, but I know some are quite finicky when it comes to mags. Some makes and models are particular on what they like, and hell, even individual ones tend to not like certain brands. It seems like whenver I see a "my 1911 isnt running right" thread, the question of which mags they are running comes up.
Having personally witnessed this behavior, I would buy one or two and see how your pistol likes them. If it runs well, go get more.
I have two mec-gars in my rotation for my Kimber which is not magazine sensative.
On a couple occasions Ive had fail to feeds because the cartridge nosedived in the magazine....these where all with my 200gr SWC light target reloads...might be an OAL issue but my Chips and Wilsons never did this. Not saying I dont trust them...but theyre range only mags right now.
A few bucks more gets you a CM or Wilson mag that has been more "bulletproof"
A the mag catch/release on a couple of my COLTS do not like to accept or release the mec gar mags. I do not remember if they shot alright. I do not want to have to wiggle the magazine to get it to latch in, and I want them to drop free on release. I gave them to some kid on the way out of the range. I have been totally happy with the Chip McCormink shooting star magazine of either style. (welded base plate of removable) The factory Colt magazines run great also.
I trusted Mec Gar mags in my 38 Super 1911 enough to run them exclusively for Action Pistol, both locally and at the Bianchi Cup. One bobble in Action Pistol means you are completely out of the running and I just didn't have any issues with the Mec Gars.
My extended base 8 round mec gar mag is one of the best mags I have. The bluing is beautiful, the spring is strong, and the follower is antitilt. The only bad thing is the spring follower and baseplate ate proprietary and they don't sell rebuild kits. Very interesting design though.
I've got 4 of the 8rd mags. 3 are perfect. The 4th runs great but does not lock back the slide after the last round. Other than that, I got nothing bad to say about them. Price was right and they work well. Going to get a couple more for the Tuarus.