.30 Caliber failure to feed

[Freischütz]

The pistol's outside is nice and clean so I assume the inside is equally well cared for.

7.65 Par is usually a reliable feeder. I have only had failures like those of your pictures when using underpowered ammunition. The minimum load with my pistol is 4.5 gr of Unique and an 94 gr cast bullet. 4.2 gr produced results like yours.

I only use handloads and don't know how powerful the factory W-W cartridges are. I know Fiocchi has a reputation for underloaded 7.65 Par ammo.

How old is your ammo? I once fired some very clean looking Winchester 7.63 Mauser ammo that was post-war. It looked great, the box looked like new, and every round failed to work the bolt of my C96. That pistol wound function reliably with 1,100 fps loads.

[w2ec]

Originally Posted by Freischütz

The pistol's outside is nice and clean so I assume the inside is equally well cared for.

Yes, the pistol is nice and clean inside as well, chamber well polished with no binding of the cartridge, action is smooth with no binding. At this point I'm pretty convinced it is a weak ammo situation. I ordered a Wolff light weight (36#) mainspring to try but it hasn't arrived yet.

The WW ammo appears to be pretty new, and I just received two boxs of the Fiocci (JSP, not FMJ) which I will try tonight. I also loaded up some rounds from the fired WW brass in .1 grain increments, I will attempt to function fire one round at a time until I find a load that will work the action to the point it successfully locks open on the empty mag. I will of course be checking for pressure signs as I go up in powder charge.

Thanks for all the helpful pointers on this forum!

[PhilOhio]

W2ec,

You are approaching this trouble shooting in a good, orderly way. My bet is that the lighter Wolff mainspring will solve your problems.

When you have a pistol for which such springs are not available, you can modify or make them from scratch. In the case of your Luger, you could remove the original spring (tricky) and put it away, buy a replacement, clip one coil, and see how that works. If necessary, remove a bit more until it works reliably with a cross section of modern ammo, or your favorite load. That's assuming recoil energy was the issue, and in this case I think it is.

I've been through this a few times, and have just done it once more, finishing yesterday. I have a mint post-war commercial Mauser HSc, an Interarms import. They are excellent and beautifully crafted pistols, but have an Internet reputation as "jam-o-matics". Why? Mauser made a few compromises on totally wrong recoil springs and didn't get the magazine follower design quite right.

I set my gun up to use both the original .380 ACP barrel and also a Mauser .32 ACP barrel.

I made my own stronger replacement magazine springs, heat treated them, and slightly modified the followers.

I then designed, wound, and heat treated three different recoil springs from two different (lighter) sizes of music wire. What Mauser had done was like putting a ten-ton dump truck spring on a VW Beatle.

After testing, I am now confident that the pistol can be trusted as a carry weapon, which was the point of the exercise...total reliability. ...which is not too common for an HSc, but should be.

The point of saying all this is to encourage some of the newer Luger people out there, to believe that most, if not all, of these functional reliability problems can be overcome. I'm only getting back into it after a lapse of many years. But my observation is that, although they have a reliability reputation somewhat like the HSc, most of that is just because they are so well made and closely fitted, and consequently they are very demanding on ammunition that is uniform, of high quality, and tuned to the dynamics of this stiff, high speed action. In my opinion, getting a fine old Luger to really run right, reliably, is worth a serious and methodical effort.

[w2ec]

Some progress has been made!

My Wolff 36# mainspring arrived today so my first step was to replace the original with the Wolff. This Wolff spring is a good 1" longer than the original I replaced. Also, just operating it by hand, it feels tighter/stronger than the original. I then fired 5 rounds (each single loaded in a mag) of the factory WW Super-X 93gr FMJ. Again, not one round locked the toggle back and the velocity was still in the 1050fps range. Not only that, but some of the rounds either didn't extract and eject or stovepiped. I really think this new Wolff spring is quite a bit stronger than the original. I then did the same with the Fiocchi JSP. Those 5 rounds also failed to lock the toggle back and and two failed to extract/eject. The toggle was closed tightly back over the fired rounds. The velocity of the Fiocchi ammo was in the 1060 fps range.

So now I moved on to my reloads. My first try was AA#5 and a 90 grain XTP .308 (not the .309) bullet. I used 5.8 grains, 5.9 and 6.0. None of these loads locked the slide back and average velocities ran 1048, 1062 and 1078 respectively. A few of these either remained in the chamber or stovepiped. Next I tried a slower powder, AA#7 with the same bullet at 7.1, 7.2 and 7.3 grains. Success! These rounds extracted perfectly when fired and every one locked the slide back. 7.1 grains gave 1119 fps, 7.2 = 1131 and 7.3 = 1145 fps. So it does seem like 1100 fps is the magic number for my Luger. It doesn't look like AA#5 will do for me as 6.0 grains is up at recommended max and still over 20 fps slow for the magic 1100fps.

There were no signs of pressure buildup on any of these loads.

Next I am going to try Unique, as I see many recommendations for this powder.

The main thing is I now know my Luger can function correctly once I get rounds reasonably over 1100fps. Now to work up a good consistent reliable load above 1100fps without any pressure signs. It was a good feeling to have the pistol functioning in the semi-auto mode, just like it should!

[G.T.]

Hi W2ec, it would be interesting to put your original spring back in and repeat the same test with your new load??... just a thought, best to you, til...lat'r...GT

[w2ec]

G.T.

Yes, good idea and yes I'm going to try that. The more I manipulate the toggle by hand the more I am convinced that the new Wolff spring is considerably stiffer than the original in my pistol. One other factor is that with the original spring I never had a round fail to extract/eject. It seems that with the "light" factory loads, the Wolff spring may be so stiff that it won't even allow the toggle to come back far enough to extract the case. When I fire the gun, I do feel recoil of course and I do sense movement of the toggle, but not much. My handloads that actually fully functioned the action were certainly brisker than the factory loads.

When I put the original spring back in I will also drop my test reloads back some as I may not need that much power with the original spring. I will also use the "tape" across the back of the frame as someone else mentioned, to get an idea of what is happening there. That will give me something else to try when I get off duty today and get home later this afternoon.

A question for the group, opinions welcome....... since I can get the luger to function fine with the new Wolff spring using my handloads that do not exhibit over pressure signs, should I eventually keep the Wolff spring in or, if I can get the pistol to function with the original spring and my handloads, would you use the Wolff spring and hotter loads or the original spring with hopefully lighter loads?

[Hugh]

These loads worked fine in my Lugers, but I am posting them for information only, use at your on risk. ( Usual lawyer induced "I ain't responsible, etc, crap!)