Change spring to use different ammo?
 

I have a 1920 commercial that functions fine with ppu ammo but doesn't cycle with Fiocchi. Unfortunately ppu ammo is not available locally, but Fiocchi is. Someone suggested I change the main spring. I'm a little hesitant to do so. Would that make it more likely for it to be damaged by ppu ammo? I'm thinking it might be best to just keep ordering ppu online. What do you think?

Robert,
is your luger a .30 cal?

If so, you may never get the Fiocchi to work, just be happy the PPU does.
It is more likely the overall lenght and power of the Fiocchi, one you can corrrect with the spring, the other not.

There are many threads on shooting .30 lugers and their problems and on Fiocchi ammo on this board. Try a search and read all the ins and outs and opinions- of which thre are many!

Changing the recoil spring in a semi auto pistol obviously can change the characteristics of said pistol with its ammo of the day.

Examples of such might be the Colt Gold Cup in 45acp or the new Coonan 357mag/38 special; either will shoot mild target loads with the respective extra spring. The springs are environment orientated, so use the right spring with the right load sorta speak. Some battering may occur if the hotter load is used with the lighter spring. The tape test can help with a visual if one chooses to do so, the other is the feel in the hand during firing.

Do you prefer the PPU over the Fiocchi? Personal preference can be in the mix more than just availability.

Springs of three weights are available from the GunSprings outfit. They come in 36,38,40 lb rates for the Luger last time I looked.

If you have never changed a recoil spring in a Luger, it is not all that easy to the new guy(or old guy like me). Takes some strength on the user's part, and of course, use the safety glasses anytime with springs. Eyes are precious. The change out of a Luger recoil spring is more difficult than the Colt or Coonan mentioned above because of its design. I suspect there are notes on this forum about the recoil spring change out procedures for the Luger in general.

You might make up your own Luger recoil spring tool, a modified awl basically or purchase one already done up. The tool will give you leverage over the old pair of pliers. allen wrench, and brute strength routines we all did at younger times of life.

Running with some ammo and not with other ammo, does not always equate to ammo relative strength, length, etc or recoil spring ability. Sometimes other parameters are in the mix such as rail fit of the recoiling mechanism to the receiver interior. So guess I am saying, changing out the spring to a lower rate is not always going to do it for you. The pistol will let you know with its shooting characteristics. Experience...........comes with doing..

Just some things to ponder.

Thanks for the replies. It is .30 caliber. I was thinking that the Fiocchi ammo is more convenient to buy, being available locally, but I've decided that since it works fine with the ppu ammo I'm not going to mess with it, I'll keep getting ppu online.

As Rick pointed out, the recoil springs are available in 3 strengths- I've bought them- but they are strangely labeled and I do not think the "strengths" labeled mean much at all.

All are too strong, IMO, for a .30 luger.

You made a wise choice to stick with what you have.

In what way is your Luger cycling improperly?

The recoil springs can age, and if one was replaced with the incorrect spring at some point, it might be shifting the "sweet spot" of the action's cycling.

Also, look closely into how you grip and support the gun while firing it. This can have more impact than the recoil spring.

If you are near Raleigh, let me know and we could meet at an area gun club to check things out.

There is a kit of recoil springs available from Wolff, but as Don says it may only complicate things to start swapping them.

in fact, if you look at our FAQ PDF, you will see that there is a wide range of recoil springs that were used in Lugers. The cycling action is balanced and dependent upon several things including the length of barrel, the speed of the powder burning, the weight of the bullet, cleanliness and lubrication, the recoil spring, your hold control and support.

As mrerick points out, there are a lot of variables in the Luger functional equation. Change one, maybe the equation becomes unstable or stays stable. Tis fun stuff really, always something to learn about these pistols.

Lots of knowledge in his posting.

Probably is prudent in changing things out is to establish a stable point and be able to return if necessary as a sanity check; if things go haywire.

Robert,

Sounds like the thing for you to do is "bite the bullet", and order the PPU in quantity.......1-2000 rounds and be done with it. Usually the price lowers when you purchase in quantity.

Really you should pick up a cheap shooter in 9mm. They are always around and my
two will eat any $9 a box ammo I buy. The 30's always seem to run well on PPU and
it solves the problems the Fiocchi ammo causes. Some here have 30's that love the
Fiocchi ,but I wasn't that lucky. Outdoorlimited has about the best price on 30's

My 30 cal. luger shoots fine with either Fiocchi or PPU ammo. I have ordered online both brands but PPU is much cheaper. I also reload 30 luger and 9mm luger to 1200fps for reliable function.

I had a .30 Luger that would shoot PPU but not Fiocchi, and I tried different mainsprings to see if if a change would improve performance with Fiocchi.

I began with a spring that was too strong, and progressively weakened it until the spring was so weak that it would not close the action on the next unfired round. I was unable to find a stronger or weaker spring that improved performance with Fiocchi. I enjoy things like this, I probably tried about seven different springs in the pistol. Needless to say I got pretty good at changing the Luger mainspring.

My conclusion is some Lugers work with Fiocchi, some don't, and when they don't it is better to use PPU exclusively in that pistol. Like others, I own some .30 Luger pistols that work fine with either Fioochi or PPU.

My 1920 alphabet likes Fiocchi . . .

There are at least three or 4 versions of 7,65mm ammo by Fiocchi;
starts out with FMJ vs PSP; then grey, purple , and black boxes- all different vintages and performance, as they are loaded to various velocities and different OAL lengths.

There are several good and long threads on 7,65mm ammo and function on the forum.