cz extended mag issue

[gator098]

until now i have always had good luck running 9mm in 40cal mags or 40cal in 9mm mags, i just got one of the cz factory 16rd 40cal extended mags with the intent of using it for 9mm, at the time i couldn't find anyone selling the 26rd 9mm mags, (the one with the long rubber sleave covering the bottom 1/3rd of the magazine)

the first issue i had was the feed lips were too wide to hold the 9mm but that was easy to fix using a highly accurate caliper and a hammer, sometimes low tech is best

the second issue i haven't been able to figure out and need some help with, i was only able to get 12 rounds of 9mm in before it wouldn't take any more, i tried 40cal and was only able to get 11 rounds, i disassembled the mag and couldn't find anywhere it was binding, i tried changing springs and put in a 9mm follower but none of it seemed to help

any ideas on what i am overlooking?

[kneelingatlas]

Can you see a butt weld inside the tube? I know the 26 is made of two tubes welded together and can hang up at the weld.

[Glk21C]

My first guess would be the tube is slightly out of spec and the rounds are not stacking well

[gator098]

thanks for the help guys, i checked the tube last night and i couldn't see any issues with welds but then again i don't have another one to compare it to, as far as the tube being out of spec - i think that may be the case, i found out last night that it seats into the gun just fine when empty but when i loaded 13 rds into it (most i could get in it) it no longer would freely seat in the grip, after the mag was about an inch in it began rubbing on both sides bad enough to where i would have had to hit it several times with considerable force for it to go fully into the grip

i guess i will be sending it back to the retailer i bought it from unless yall think it would be better to send it to CZ directly

[gator098]

update on the mag issue - i had left the mag with the 13 rounds i could get in it for a week to see if would help, took those rounds out and reloaded again could only get 13, out of frustration i slammed the base of the mag onto my reloading bench, when i did that i heard the rounds move a little so i tried to put another round in, it went in very easy but the next one wouldn't go, slammed it again loaded one round super easy wouldn't budge for the next, slammed it again etc etc etc, i did this until all 26 rounds were loaded, i have had mags that the last 1/4 of the rounds or less were hard to load but this is a bit ridiculous for it to be a tight spring, i am guessing something is up with the follower or the tube,

any new suggestions on what i might need to take the dremel to?

[gator098]

update to the update - i think the suggestion that the tube is out of spec is correct, i had loaded it using the above method and let it sit for a week hoping it would break -in the spring, no such luck, i had the same trouble when i went to reload immediately after emptying it, on top of that once it was loaded again with dummy rounds i went to seat it in the gun to see if all the rounds could be hand cycled through, it was then that i discovered that the side walls of the mag were preventing it from going more than an inch into the grip, aarrrrrgggggghhhhhhhhhh!!!