Thanks to you folks I have found the problem.  The K10 mag is a few thousands of an inch longer than my good orange follower T mags.  After sanding down the K10 front and back, and then marking those areas with a black felt tip pen, I inserted the K10 all the way in and withdrew it by hand (takes a little effort).  I now see where the binding is located and will work on reducing it hopefully to the point of elimination.  Ideally I would like the K10 mag to work as smoothly as the T mags but I will take what I can get.   HW

The K10 mag body, sans everything else, will not insert fully without force.  Problem starts about 2/3's of the way in.

Three reasons the problem is not the gun:
1. When I returned the piece to EAA after I purchased it in mid 2007, their shop people had no mag issues with it (or did not tell me about any).
2. The returned pistol had an additional mag (7 round) with it that has worked fine.
3. The additional mags I purchased in 07 (red follower) had no problems.
I had no mag problems until I attempted using recent ones marked "K10" on the right panel near the back.  My 3 functioning 15 round mags are marked "10mm" on the lower right hand panel toward the back, with a nearby letter "T" framed within a triangle with rounded corners.  The mags all have orange followers.
I tried to insert the K10 mag after I removed the baseplate and spring/follower, but still had the same problem noted above.
Will try to get pictures.  If anyone has both the 07 orange follower mags and the K10's see if you note any differences between them.
Mec-Gar no longer lists mags for my Witness on their website.  Does anyone else make them?       HW

The 3 to 5 K10 mags I tried (from EAA and two other merchants) did not fit.  That is why after reading the comments here I did a visual comparison between my old mags and the non-fitting K10s and noticed the major differences.  I tried sanding the upper third of the K10 I kept but it still inserts only with effort.

Unless I can obtain the older mags I need the services of a good gunsmith to modify the K10 mags to fit, if it is possible.

I have tried mags from EAA and from Midway.  All stamped K10 on the right side near the bottom.  All of the black follower K10 mags stick in the mag well when inserted about 2/3's in.  EAA's Sales VP told me that since the pistol was out of warranty that I would be on the hook for all shipping and possibly repair charges.  Emailed Tanfoglio in Italy but no reply.  Hennings responded to me but could not help.  I do not want to alter the mag well if at all possible, so I am trying to obtain the older mags and/or mag bodies.
Will try to get pics of the two types of mags.  Seen from the top my old mags are nearly rectangular with a slight back taper.  The K10 front is rounded with a more pronounced back taper.
Pistol is large frame Witness Match, as marked on left hand side of the gun.  Barrel hood marked 10mm.

Thank you for the replies.  The upper third of the new mags cause the problem.  Comparing the properly fitting mags with the new one shows different upper tapers, different lip designs, and different left/right side configurations. Should have looked more closely before.
I need to take pistol and mags to a good gunsmith to get the new mags modified. 
Mods I failed to mention earlier are an extra-power firing pin spring along with a Hennings extra-long firing pin.
If anyone has any 2007 or earlier 10mm full size mags he wishes to sell please contact me.   Properly fitting mag bodies alone would be good, since I can purchase the internals elsewhere.

Thanks for the reply, sqlbullet.  Mag hangs up in well long before the mag is seated. Removing the base pad and then inserting makes no difference with seating.  Something wrong with the new mag's cross-section.  Does anyone else make mags for my model pistol?

I have a 2007 10mm Witness Elite Match.  The current EAA replacement mags do not fit without forcing, especially as I move the mag up into the well, and cannot be removed without effort. I do not want to change the magwell's interior dimensions.  Has anyone else experienced this, and are there any solutions?  I am reluctant to send it back to EAA, since they have exchanged several mags with me as well as base pads.  I also had an unproductive conversation with one of their execs that makes me hesitant to return it to them. 
When I purchased the WE Match in 07 it came with a burr on the muzzle crown.  EAA had me return it to them, and sent it back to me two days later with the following mods:  fitted Lothar Walther polygonal barrel, ambi safety, and a spare 7 round mag.  Pistol shoots to point of aim  anywhere out to 23 yards.  Only mods on my part are a 18lb Wolf recoil spring and a Springco Recoil package. The two additional mags I purchased in 07 fit fine and have only had their springs replaced with Wolf items.
If this question belongs on a different part of the forum please let me know.