The P38 to P5 Magazine Conversion Thread

[Pilotsteve]

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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

[Pilotsteve]

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

[DennisV]

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.

[MGMike]

Originally Posted by Pilotsteve

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

[Pilotsteve]

OK guys here's what I managed to accomplish today. Load it up in high-def, maximize your screen and enjoy:

Walther P38 to P5 magazine modification test. - YouTube

Walther P38 to P5 magazine modification test. - YouTube

More to come later - I've got more pictures I need to post first.

-Pilotsteve

[Pilotsteve]

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

[MGMike]

Originally Posted by Pilotsteve

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

[Pilotsteve]

I'm packing my bags right now... range report with the modified magazine forthcoming.

-Pilotsteve

[AoxoMoxoA]

Originally Posted by Pilotsteve

I'm packing my bags right now...

Don't forget your helmet...

[Pilotsteve]

IT WORKS! No need for me to describe the results... Just watch for yourself:

http://www.youtube.com/watch?v=OXP2Z1z3pEI

http://www.youtube.com/watch?v=OXP2Z1z3pEI

Eureka. Once I make my toolset for the P38 magazines I'll be able to crank these out by the truckload. Fantastic!

-Pilotsteve