I have an EAA Witness Elite in both 40 S&W and 10mm Auto, the later is a Conversion. My two 10mm Auto Magazines were awful to load not because of a wrong mag. or such they just are tough to reach the 15 round capacity, I have always been able to hand fill with 10 rounds but beyond that It was a Real Pain in the Thumb and Heal of Hand trying to get the Stagger stack to align to allow the next round.
I went to my local Gun Guru and told him of my problem, after proving to himself it was just a real chore he suggested an aid to load it.
He showed me a couple of different ones which I was not real impressed with then he showed me the one I bought. It was slick fit multiple Mags from Single to Double Stack, well made of Quality Material, best of all it worked.
The Product is offered by Butler Creek, it is called UpLULA Universal Pistol Magazine Loader, mine is stated to load 9mm, .357, 10mm, 40 S&W, and 45 ACP cal rounds and magazines.
This tool is not cheap but it is worth the price, before I forget I did try it out on my Wife's .380 Auto Worked great. The Mfg. states many other versions for Rifle as well and is working they said n one for .22 Ca. including the 10-22, that should be interesting.
Normally I would not post a Mfg. Product of a Gun Forum, but due to what it is and how well it worked I had to share it with you.
www.maglula.com