Receiver rail guide.

[Sieger]

Originally Posted by postino

It's not all dependent on the ammunition. A weak recoil spring could cause excessive pounding on what I call the 'abutment'. Here's the areas I am referring to - yours compared to my commercial...

It looks like yours has taken a bit more hammering than the commercial...And yes, being hammered from both sides could cause that 'fin' to work-harden/fatigue and break...

There really isn't any other stress on these 'fins'...Under normal operation...

If it were my Luger, I would be concerned about the breech block cracking...

But everything is relative! If you're happy with the way it functions, then that's all that matters!

Hi:

The frame on the right looks like the springs and ammo have been properly matched, as their has been no breach block slap. The Luger was not designed to absorb a regular pounding at this point, and as previously stated, this pounding is a major cause of mechanical failure with this design.

The Luger with the missing fin looks like it has taken quite a lot of pounding here and has failed. I agree with you that weak springs and/or too hot of ammo is the cause of this condition.

Original DWM military ammo for the 9mm, circa WWI, was 123 gr bullet at 1,076 fps, a rather middle of the road load by today's standards. The much vaulted Commercial Winchester white box is 115 grs at 1,190 fps (according to the Winchester web site) or 11% over original specs. The current U.S. Army Nato load is 121grs at 1,260 fps or 17% over original specs. I believe that regular use of the "hot stuff", even with springs in spec, will eventually lead to problems.

Now days when I'm shopping for a Luger, I'll try to examine this area for ususual wear. If it has taken a battering, I'll usually pass on the pistol and find one that hasn't.

I handload for all of my shooting with my Lugers, and handload to the original specs. These loads are also extremely accurate.

The Wolff #38 is the standard weight spring, but with "hot stuff", I'd try the 40 pounder.

Sieger

[MFC]

Try putting a piece of freezer or electical tape on the back of the frame where the rear toggle hits. If ammo and springs are in spec, it should leave a dent in the tape. If the tape is mutilated, either the spring is too weak or the ammo is too hot.

[Sieger]

Originally Posted by MFC

Try putting a piece of freezer or electical tape on the back of the frame where the rear toggle hits. If ammo and springs are in spec, it should leave a dent in the tape. If the tape is mutilated, either the spring is too weak or the ammo is too hot.

Hi:

Excellent advice!! This is low tech, but has been a standard test for years.

One additional thing. When there is breach block slap, you can really feel it in the web of your hand upon firing the pistol.

Sieger

[1969goatman]

SO, guys what is your final answer here. I use nothing but factory Fiocchi, (The Winchester is too high in price and ballistics are the same) Handloading ammo for me is just totally out of the question. Buy a 40 pound spring? ALL available .30 Luger I read is rated at 305 ft Ibs, and 1220 FPS. so.......... A spring is 7 dollars, big deal.

[Armin]

Hi guys,
if we want to compare the applied load that takes effect on a Luger during a shot, we must not compare the muzzle velocities of the bullets, but we must compare the momentum meaning muzzle velocity*bullet weight.
According to Newton's law the bullet's muzzle momentum causes the same but reverse momentum on the breech block and finally on the frame. That means that a light bullet with a high muzzle speed has an enomous energy but only a moderate momentum.
I regularly shoot Magtech 95gr ammunition with a muzzle speed of 1345fps in my shooters. Seems to be very hot, but the momentum is fairly soft.
Armin.

[borzellot]

I have to add something here. The receiver is not slamming into the frame. It is the rear portion of the breechblock that is cushioned under spring pressure from the striker retainer pin. The striker retainer is what is hitting this area of the frame and is the abutment.

Frame fins crack in time, especially a weapon almost a century old, although one might say under normal operation these fins sustain no wear? But we can speculate that it is fact that this area of the frame takes a tremendous pounding from the returning toggle, multiply that by 8 rounds over and over , over a period of years and than decades and the steel just gets brittle.

What happens is, the movement of the toggle, down on the frame through the years moves all the molecules in the steel to a head, just like in the striker, (Why dry firing lugers is not a good idea) and it just gets old and brittle and breaks off as the molecules all shove into the corner of a fatigued piece of steel. . As far as the breechblock cracking? It is not the breechblock that is hitting this area put the striker retainer, and this is under spring tension and absorbs impact. As we know. The weapon is just old. I have seen many Shooter grade Lugers with these fins long broken off.

There is like 1/16th of an inch of space were the receiver stops short of slamming into the frame. It is my opinion that factory spring, unless miserably weak, should not be changed. iF THE GUN WORKS , LEAVE IT ALONE