Ran some 200gr xtp underwood, 180gr underwood tmj, and 200gr wfngc doubletap yhru our gen 4 glock 20 and 20sf. I had no stoppages with either setup but with a heavier spring and lonewolf barrel in the 20sf I had 4 malfunctions out of about 20 rounds.  They were jamming up partway into the barrel .  Is that from a too tight chamber?

Sounds like a ramp issue to me

It could be the tipping angle, this would include the wide meplat and cartridge overall length.

Read through this info as it is relative to the 10mm cartridge and chamber feeding; pay attention to the tipping angles and other info.  There is plenty info to help you understand some issues.
http://38super.net/Pages/Overall%20Length.html

this is what the stops looked like

polished the top of the feed ramp where it meets the chamber, along with the chamber itself and the feedramp as well.  this way the nose can't "catch" on any rough areas and the brass doesn't catch on the sharp transition from feedramp to chamber.  I hand cycled a magazine of the 200gr XTP and had no stoppages. Next will try it at the range and see. Hopefully it works as the lonewolf is an older barrel with the "tight" chamber tolerances.  If it doesn't I'll probably keep the barrel as a "range" barrel, and get a storm lake or KKM that have slightly larger chambers to use as a hunting barrel.  I really like the improvement in accuracy from the aftermarket glock barrels though.

Sounds like you have been studying the situation...

How was the breech face?  I have seen some brass build up on my breech face at times, combination of softer brass casings and slight roughness.  I do clean and wipe a light coat of gun oil on the breech face of my guns to help.  The thought is to allow the cartridge's head, to slide up the breech face easier with less drag, as the slide moves into battery.

Another thing is magazine feed lips, inspect for damage, stretched outward, pushed inward, angle of the round as it sits inside...is it nosed up too high.  Compare to other magazines as well.

Is it better to use a loader to get that last round in vs pushing it down  by hand with the next cartridge?  I finally have an uplula but rarely use it since its in the fiancees range bag.

Quote from: The_Shadow on April 12 2014 01:37:56 PM MDT
Sounds like you have been studying the situation...

How was the breech face?  I have seen some brass build up on my breech face at times, combination of softer brass casings and slight roughness.  I do clean and wipe a light coat of gun oil on the breech face of my guns to help.  The thought is to allow the cartridge's head, to slide up the breech face easier with less drag, as the slide moves into battery.

Another thing is magazine feed lips, inspect for damage, stretched outward, pushed inward, angle of the round as it sits inside...is it nosed up too high.  Compare to other magazines as well.

I cant recall issues with  breech face build up but ill check when I get home.  Thanks for the help fixing this up.

Quote from: mag360 on April 12 2014 08:41:41 PM MDT
Is it better to use a loader to get that last round in vs pushing it down  by hand with the next cartridge?  I finally have an uplula but rarely use it since its in the fiancees range bag.

Don't know if it makes a diff other than on a new mag, your fingers will be sore! 
I use a loader to fully load the new mags for the first season so the springs loosen up a bit... later I don't.
I also have always rapped my mags to seat the bullets back if it makes a diff.

Update:

With the polished feedramp, and top front of chamber, along with polished chamber on the lone wolf barrel I had NO stops with the 200gr underwood xtp.  Very stout even with a 20 or 22lb spring. Brass was at my 4 o'clock about 12' away. Very accurate from 10-12 yards away. A 10 shot group was like 2" off hand. Many shots touched each other!