CZ P07 DUTY .40 S&W magazine Question

[Larry F]

I've looking for input on replacing the non Drop Free 40 caliber magazines in my first generation CZ P07 Duty .40 S&W pistol with newer CZ P10 Compact 15rd 9mm magazines which fit ok, seem to function and are Drop Free.  Can anyone with experience comment?  Thks.

[M1A4ME]

Non drop free?

I have two DUTY P07's in .40 S&W and the mags that came with them in the box as well as the later mags (and P09's mags as well) I've bought.

Never heard some wouldn't.  Could something else be causing that issue?  Hopefully someone here can help if they had the same issue and overcame it.

[Larry F]

Have 2 magazines that came in box with 2010 vintage pistol and 1 I bought (new)last year.  All are identical dimensionally.  Problem is the front to back length of the magazine measures 1.68" and the top portionof the back of the magazines drag against the front surface of the rear insert when the magazine is inserted. Seated there's enough friction to hold the magazine in place. 

Conversially, I have 2 CZ P10c 15rd 9mm magazines that are identical to the P07 Duty magazines except the front to back length measures 1.26".  The .0006" delta is enough that the magazines don't drag and do drop free. 
 
I went thru the common problem explanations early on and accepted the flexible polymer, hard hand gripping, tight fit, mold lines, etc. explanations.  Just got the tip from David at CGW.  Was initially concerned about the difference in feed lip width but have worked OK so far with the 9MM followers and springs and also when I switched to the 40 caliber followers and spring.  so far, so good but am looking to see if more info is available from more seasoned users like you.  Thks for input.

[M1A4ME]

Never heard of any of those issues with the frames.  I did hear about frame swelling on the early guns and that was something they were supposed to have fixed with the transition to the non DUTY marked guns/frames.

The DUTY P07 .40 I bought (appeared to be new in the box) a couple years ago still had paper stick on tags on the magazines that labeled them as "CZ07" magazines.  Mine was a 2010 model (the second one I bought).  The first one I bought 12 years ago or so was a 2011 made pistol.  It has the beavertail, trigger and slide of the DUTY guns but the trigger return spring of the 2nd model P07 and the P09 pistols.  A transition pistol you could say.

Glad the newer P10/P07 magazines are working for you.

Are the 9MM magazines allowing the .40 S&W followers to rise up enough to lock the slide back?  I'd think they'd be just a tiny bit wider than the 9MM followers and maybe run out of upward travel earlier as the last round is fed from the magazine.  Not the same issue - but I converted some 9MM Shield Plus magazines to run .40 S&W and tried a .40 S&W follower in one of the 9MM Shield magazines.  It would not go high enough in the 9MM magazine to push the slide stop lever up to catch the slide.  I had to work on it to make it narrower so it would lock the slide back.  I ultimately went back to 9MM followers to feed .40 S&W rounds and it worked fine at the time.  It's a project I need to get back to as I catch up from not getting much done the last few months.

[M1A4ME]

I just noticed, after all these years, there is a sticky right at the top of the sub forum on sticking P07 magazines.  Dates back to 2009.  Seems a lot of new owners had the issue.  Take a look at it if you haven't seen it yet.

https://czfirearms.us/index.php?topic=23688.0

[Larry F]

Need to correct my measurements to make understanding the issue clearer.  P07 ,40 mags measure 1.268" front to back while P10C 9mm mags measure 1.260" front to back.  the upper edge of the .40 mag contacts the front surface of the rear insert and is squeezed to the point it has to be pulled out of the grip when the mag is seated while the 9mm mag just grazed the insert and will drop free.

the tight fit I see with both mags is in the side to side fit up.  There's not much clearance with the trigger bar nor the trigger bar spring.   The mag seated insertion depth looks identical including the follower heights.   The .40 follower does set a little lower in the 9mm sleeve but  surprisingly will still lock the slide back.  The 9mm sleeve has a higher cut out position for the P10c and a 2nd lower cut out for the P07 frame.  The length of taper down the the feed lips is also the same. 

I was dubious about how well the larger .40 cartridges would feed from a 9mm mag but so far so good.  The .40 top follower does have a little more rounded profile to fit the larger cartridge diameter but not much.

[Larry F]

Request of M1A4ME:   I think your initial pistol is a 2nd Gen P07 Duty S/N Bxxxxx from the description and your backup is, like mine, a first Gen S/N Axxxxx ( mine also has a 10 (2010) stamped in front of the S/N on the barrel to show the year).

What would help me is for you is for you to measure the front to back distance of both magazines, that came with each pistol, remove the slide on each pisto, observe how the magazine fits as  you insert it and if/how the magazine binds up and which, if any, won't drop free.

What I see is the back edge of the magazine is loose until the back edge just starts rubbing against the front surface of the rear metal insert and tightens as it moves upwards. Actually moves the collar on the decker shafts a bit as it seats.  Your info may give me a little clearer picture of what's really happening. 
 
Ref your backup pistol.  My pistol had a frame bulge (the short 90 degree leg in the slide stop spring was creating a round bulge in the side of the frame) which I was able to eliminate by switching to the insert like your Bxxx S/N uses and ironing the bulge out with low heat and a clamp.  mine also showed some frame swell on the right side of the front insert (the front 1/3rd of the insert length is tight but the rear 2/3rds has an open .010 gap of separation - looks to go about 1/4" deep from the top of the insert then closes.  The bulge hasn't returned and the swell hasn't changes over time.  The remaining frame to insert surfaces haven't shown a gap. 

My pistol functions OK as is but I tend to go the xtra distance when I  take on a project.  Thks for your help.
   

[M1A4ME]

Okay, got back from a birthday party/dinner (not mine) and got some measurements and pictures.

Info  1st pistol I bought has a 2013 date on the slide.  Serial # B3975XX
        2nd pistol I bought was a 2010 date on the slide.  Serial #A7531XX

Magazines  Two from the older pistol box.  One from ?  I have 7 P07 magazines in the same place as the pistol and don't know which of the seven came with the pistol.  I measured both the older pistol magazines and one of the magazines I've used in the later P07 for years.

I measured front and back right on/level with the slot the magazine catch goes into and again on/level with the hole that indicates 12 rounds in the magazine.

2010 mag #1 measured 0.854 inches front and back at the mag. catch button hole.  It measured 0.852" front and back at the 12 round hole.

2010 mag#2 measured 0.856" at the front at the mag. catch button hole.  It measured 0.854" at the back of the magazine at that level/height.  At the 12 round hole it measured 0.852" front and back.

The later mag. measured 0.852" front and back at the mag. catch hole.  It measured 0.852" at the front of where the 12 round hole is and 0.851" at the rear of the mag. at the 12 round hole.

I took some pictures, too.  It'll take some time to get them transferred to my laptop, get them sorted/organized and then put them in imgur so I can post them here.

The spot that both pistols seem to "catch" the magazines (all three of them) is that same spot you described.  The metal insert in the frame.  The back of the magazine contacts it and slows down the rest of the insertion.  The pistol I bought first and carried the past years has a discolored spot on that insert.  Sort of brown looking.  The older but less used pistol seems to have a wear mark through the finish as it looks a little shiny and in the same spot.

None of the magazines will drop free from either frame unless the slide stop is inserted into the frame.  Then the follower makes contact with the slide stop and slightly compresses the magazine spring as the magazine finishes insertion and locks in.  Once the magazine release is pressed the magazine spring/follower push against the slide stop and push it hard enough to force it past the snug spot where it then continues to fall out of the frame.

When the pistol is fully assembled the empty mags. "pop" out every time I press the magazine release.

Hope this info helps in some way.

[M1A4ME]

Old P07 with the newer magazine.



Old P07 with a mag. that came in the box with it.



You can see both magazines stop at about the same point with enough friction to hold them in place without falling out when the frame is held vertical.  Same in both frames with both magazines.

Newer frame with the newer magazine.



Newer frame with one of the older magazines.



Older frame with sort of brown spot where the magazines has barely rubbed it.




Newer frame with the shiny spot where the magazines have rubbed through the finish.



Sorry, now that I've posted this I realize the pics are so small (last two) you really can't see the wear spots on the rear metal inserts.

[Larry F]

Big help - believe it or not.  Your magazines fit and drag identically in the frame with the way mine does.  Can you confirm your pistols have manual, not decocker safety? 

If so, my issue is clearly with additional interference between the spring loaded collar on the decocker shaft and the magazine as the magazine is seated.  My P07 magazines function just as your's when I depress the decocker lever while my slider shorter P10c magazines just clear the decocker collar as they seat and do drop free.  Our measurements are reversed - your front to back #'s would be my side to side #'s. 

In retrospect, I may have created the problem. Early on, I my decocker would sometimes fail to function.  CGW guys advised the pressed on collar had shifted position on the decocker shaft and needed to be reseated.  I did and glued it in place with green locktight - works fine but I may not have rotated it back into the right orientation.  I did buy a $3 replacement collar and can try a fix if I can locate it in my box of 1000 P07 parts - will switch to manual safety in mean time to confirm problem.

Your pistols look to be in fine condition - might consider switching the 2010 front insert to the 2013 version it looks like you don't have any frame bulge around the slide lock spring but do have a little frame separation from the side of the front insert.   Again, thks for help.