Walther Forums banner

The P38 to P5 Magazine Conversion Thread

34K views 86 replies 15 participants last post by  bigfatdave 
#1 ·
This discussion redirects from here. I think it's appropriate to start a thread specifically addressing the discussion of converting Walther P38 magazines to function properly in the P5. Those new to this discussion should read through the posts from the link above and continue here.

I have given this some thought throughout the day today and realize I don't even need to order the keyseat cutter. I may not even have to order anything because I have a multitude of endmills in stock and may have one of the appropriate diameter already. I've realized the need for squared edges in the slot is unnecessary because it'll fit provided I extend the width of the slot a bit. Also, there is no need for me to build any sort of fancy toolset either. This is actually going to be quite easy for me to accomplish... I'll explain.

All I need to do is secure the disassembled magazine tube horizontally in the Kurt vice on the Bridgeport deck, pick up my "zero" on the lower aspect of the dip on the top rear of the P38 magazine and track my "Y" axis to the appropriate distance. As can be seen in this picture, it'll be approximately 124mm after taking tool width into consideration. Observe:



Ultimately, the top of the magazine lips should present thusly if the job is done right:



And when a cartridge is loaded, the top of the round should present approximately 12mm above the plane of the top of the frame proper:



Any higher and the risk of magazine fouling/crashing the slide is apparent, and too low could result in the breech block striking the casing too high, causing an inherent nose-down moment when the cartridge is stripped from the magazine - leading toward it plowing nose-first into the feed ramp.

If all goes well, I'll be test-firing one of my P38 magazines in my P5 Sunday afternoon.

-Pilotsteve
 
See less See more
3
#2 ·
One more bit of geekery before I hit the hay tonight. When all is said and done, it appears the butt of the P5's grip will feature a slight magazine protrusion which will appear something like this:



I really don't think it'll figure into the shooting equation for those who use a normal grip on the weapon when firing. "Cup & Saucer" shooters might feel something unfamiliar though.

-Pilotsteve
 
#3 ·
I'm really surprised to see the much effort that you guys undertake to get P5 magazines. Are those P5 magazines really that scarce or is it just a matter of fun?

other than that, it is ofcourse a great experiment and I'm positive that the magazines will function this way, but just watch out that you don't use your second hand to support the gun under the grip.
 
#4 ·
All I need to do is secure the disassembled magazine tube horizontally in the Kurt vice on the Bridgeport deck, pick up my "zero" on the lower aspect of the dip on the top rear of the P38 magazine and track my "Y" axis to the appropriate distance. As can be seen in this picture, it'll be approximately 124mm after taking tool width into consideration. Observe:



Ultimately, the top of the magazine lips should present thusly if the job is done right:



And when a cartridge is loaded, the top of the round should present approximately 12mm above the plane of the top of the frame proper:



Any higher and the risk of magazine fouling/crashing the slide is apparent, and too low could result in the breech block striking the casing too high, causing an inherent nose-down moment when the cartridge is stripped from the magazine - leading toward it plowing nose-first into the feed ramp.

If all goes well, I'll be test-firing one of my P38 magazines in my P5 Sunday afternoon.

-Pilotsteve
Steve: This is a very commendable pursuit. Please allow me to make a few observations.

1) Locating the slot to be cut by reference to the curved contour of the rear spine at the top is unreliable. There has been considerable variation in the size, shape and contour of that area over the years; and some P38/P1 mags are not identical to the P5 in this respect.

2) The only really reliable datum is the top of the feed lips at the rear, which will require an angled fixture to match it.

3) The height of the feed lips is the only reliable datum for measuring how high the inserted magazine should extend above the top flat of the frame. The height at which a cartridge is presented can vary, depending on several factors, including variations in the follower, the type of ammunition and the number of rounds loaded. N.B.: If the magazine lips are pushing up on the ejector when the mag is latched, it's too high.

4) Even though the P5 latch will limit the upward travel of a P38 magazine after it's latched in place, it does not prevent excessive upward movement until it's latched. Given the tendency of some people to vigorously slap the magazine home, some other positive means to limit the depth of insertion is desirable. I've seen a lot of magazines with mushroomed lips caused by slamming the mag upward into the underside of the slide. A shim brazed to the top of the floorplate would be a permanent fix (but would destroy P.38 interchangeability), but even an o-ring of appropriate thickness pulled down over the mag body to rest on top of the floorplate might work as a serviceable spacer.

5) Including a P5C mag catch is not that complicated. The only critical part of the notch's shape is the straight cut at the top, which must be correctly angled. It need not be punched; the cut can be made with a small cutter or abrasive disc; the rest doesn't matter too much as long as the hole is small enough that the follower and spring coils can't snag on it. The downside is that the notch won't be hardened (it probably is in the originals), and may wear prematurely unless care is taken with latching and unlatching.

M
 
#6 ·
Here are some pictures of the way the modified P38 magazine fits inside the frame of my P5. The geometry and position of the lips in the frame is quite nearly identical, and with a cartridge in the magazine it appears to be in accordance with my observations with the stock P5 magazine above. Observe:




Mike, thank you for the sage advice; I'll take each lesson in turn.

1) I agree, but I was careful to ensure the area I took my zero from was of similar design between the magazines. I suspect a great majority of magazines will have similar contours in this area but I'll be sure to watch for any variations. Taking #2 to heart, I have a feeling I might be making a great many slots in the near future if this does in fact work. I'll make a toolset out of aluminum designed to hold the magazines in exactly the same way every time (utilizing the top of the lips as zero) so I can precisely repeat the process over and over. You can see in the video how I merely clamped the padded magazine tube in the vice - that's not the way I'd do it in the future.

3) True, Sir. Also, the lips must never be allowed to contact the slide when pressure is applied to the magazine. After I'd finished cutting the slot I pressed the butt of the magazine up against my cousin's shoulder, leaned into it, and worked the slide back and forth. There were many kilograms of pressure applied to the magazine between us and it could not be made to contact the slide.

The magazine must not present too low in the frame, either. This would cause the follower to seat too low to lock the slide back, and worse - the cycling of the cartridge may become unreliable because the breech block will not strip the cartridge from the magazine at the right angle, causing it to plow nose-first into the face of the feed ramp.

4) Again, you are correct Sir. Of course, one cannot idiot-proof everything. Those with a brain betwixt their ears know there's no need to bang the magazine into the pistol, but Ogres are everywhere. One would have to drive the magazine into the P5 with some force in order to "beat" the catch tab but I suppose anything's possible. As long as people behave themselves, there shouldn't be any need for shimming (or otherwise altering) the base of the P38 magazines for this trick to work. "Cup & Saucer grip" shooters won't cause problems either. The tab really does lock that magazine in place good and firm; it'll do well to prevent all but the worst shenanigans.

5) Not wouldn't that be something? I just looked at one of the P5 Compact magazines I have and yes, I could very easily notch that out to work beautifully. In fact, I even have the correct ball-nose endmill to replicate the radius on the bottom (which is unnecessary). Sign... but why would I take on this burden when I have no elusive, delicious P5 Compact? Truth be told I'm not really lusting for one myself because my P5 sure cures all of my 9mm wants. Of course, if someone were indeed brave I could attempt to notch one of their P38 magazines for use in the Compact modell but there is no way I could test-fit after the undertaking. Those would indeed be murky waters.

-Pilotsteve
 
#7 ·
Here are some pictures of the way the modified P38 magazine fits inside the frame of my P5. The geometry and position of the lips in the frame is quite nearly identical, and with a cartridge in the magazine it appears to be in accordance with my observations with the stock P5 magazine above. Observe:




...After I'd finished cutting the slot I pressed the butt of the magazine up against my cousin's shoulder, leaned into it, and worked the slide back and forth. There were many kilograms of pressure applied to the magazine between us and it could not be made to contact the slide.

...
Well done, Steve.

M
 
#15 ·
Having taken Mike's advice to heart, I have determined using the "U" shaped cutout atop the rear of the P38 magazine as the zero reference for measuring the distance to the slot is unreliable. In fact, this position is not nearly as critical as the datum that should be used: the top of the feed lips of the magazine.

Note how far the magazine lips protrude from the top of the frame of my P5 with a factory magazine installed:



This distance is critical. As discussed earlier, this is the true critical position that must me maintained for the conversion to work. If done properly, this is how the converted P38 magazine lips appear when in the P5:



Therefore, in order to assure my X axis distance is correct every time (and allowing for magazine variances), I should use the top of the feed lips as my zero datum as such:



This way, I'll get it right every time. All I'll have to do is design my toolset to allow me to simply insert the P38 magazine allowing the top of the feed lips to rest on a known stop. Clamp it in, and I can find zero every time. Once I determine the new X coordinates I'll be able to repeat with .0005" accuracy.

-Pilotsteve
 
#16 · (Edited)
The amazing part is that the P-5/P-38 mags are now among those prohibited in NYS.
 
#18 ·
Drafting the toolset

Wow... either I have no life or I'm too nerdy I'm not sure, but when I got home from work this afternoon I sat down and sketched my idea for the toolset. I'll make it tomorrow out of aluminum; with this rig I'll be able to achieve repeatably and ensure the slot is positioned precisely.



Once secured on the deck of the Bridgeport, I can take my zero from the reference hole. From this position I merely need to move my "X" axis to the proper coordinates (to be determined tomorrow) and make the cut. The magazine will be positioned in the toolset by referencing the top of the feed lips as the datum as in #15 above. It is then secured at the rear by a block which is tightened with a machine bolt. The side-view sketch is not exactly to the right size (and yes, the magazine is upside-down) but you get the idea:





-Pilotsteve
 
#19 ·
Magazine toolset fabrication.

Here's the work I did today. The toolset is finished; tomorrow I'll be able to determine the coordinates and start converting!







You can see how the toolset uses the top of the feed lips as the zero datum, which is critical. I can pick up my zero from the reference hole, move the X-axis to the correct position and make the cut in precisely the same spot every time.



-Pilotsteve
 
#23 ·
This is how it's done.

I made my first run today, converting some P38 magazines a few brave forum members have sent my way. Here's how it's done - remember it'll look much better if you open the video in Youtube and viewi it in 720HD:



The finished results:


I have not test fired these magazines yet. It's bone cold outside today (-10°C or 14°F) and I don't have any ammunition anyway. I can verify they lock the slide back properly in my P5 and they certainly position themselves exactly the same in the frame as the magazine I did test-fire. I see no reason why they shouldn't work... I'll probably pick up some ammo later this afternoon and see how ole' man Frost is feeling tomorrow.

-Pilotsteve
 
#25 ·
Muy bueno.
 
#27 ·
I'm tossing the magazines into my range bag as I type... you guys owe me one big time because it's minus 7°C (~19°F) outdoors right now and it'll probably be MUCH colder at the range. I don't even want to think about the windchill; if nothing else this will be a true cold-weather function test for my P5.

I have half a mind to practice some "Vehicular Tactical Ops" and just roll the window down on my truck and shoot with the heat on!

-Pilotsteve
 
#29 ·
Here's the results! Of the five P38 magazines I modified, four of them worked flawlessly with cheap, dirty Remington UMC range ammo. The one magazine that failed to function has a follower that binds in the magazine tube - it's completely unrelated to the modification.



This proves it can be done! I'm willing to do this modification for all Walther Forum members - PM me and we'll work out the details if interested. I think we can safely state it is possible to make functional P5 magazines out of plentiful, low-cost P38 stock. This is fantastic as it opens the doors for folks who are hopelessly at a loss locating P5 magazines for anything less than a week's pay.

-Pilotsteve
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top