W231 + 115gr FMJ

[azlaw]

So, I have a 9mm 42 byf, and it seems to work. Now I need some ammo that will work reliably. My eye casts about the shop and falls on a large quantity of W231 and a small heap of old 115 gr FMJs. So, that's what I plan to use for the next little while. Tried my pet Browning High-Power "wimp load" at 4.3 gr of 231 with OAL 1.140", but every second or third round misfeeds, nose high. So, anyone have a suggestion? Charge and OAL?

231 builds pressure pretty fast, so I hestiate to turn up the heat too much on a 1942 Nazi wartime pistol. 5.0 gr looks like about 31,000 CUP. I have heard the usual chatter about "Lugers need hot loads", but I am a bit skeptical on this.

H

[Sieger]

Hi:

Here is what has worked for me.

OAL with round nose bullets, start off at 1.173 inches. Fill your magazine with 8 rounds. If the Luger feeds the first and eighth cartridge the same way (manually), you are ok. If not, adjust all 8 cartridges shorter by 1/1000th steps until all 8 do feed properly. Now you are ready for reliable firing function.

As to charge, start low so that the pistol will not function. Go up 1/10th of a grain, in three shot groups, until full function is obtained. When full function is obtained (totally reliable feeding of 8 rounds from the magazine and proper hold open after the 8th round) you have obtained the right load for the set of springs your Luger has in it. Loading more than a few 10ths hotter than this basic load should begin to cause jams pretty quickly.

Now, that wasn't so hard after all.

Springs are really the key to healthy Luger function. Without proper weight springs, the timing of the action between the magazine spring and mainspring will be out of "tune" causing havoc to proper function.

Hopefully, someone will soon be making proper Luger springs.

Sieger

[stefanosg]

I used a factory round and placed it in the seating die position on my Dillon. I then adjusted the seating die so that it hit the top of the bullet.

[Sieger]

Originally posted by stefanosg
I used a factory round and placed it in the seating die position on my Dillon. I then adjusted the seating die so that it hit the top of the bullet.

Hi:

Most modern factory rounds are too short to properly function in a Luger.

AOL is vital because of the steep angle of the Luger magazine. This is also why the magazine spring must be so strong.

If you don't have a way to properly measure OAL, RCBS sold me a little cheap caliper that I have been using for the last 27 years or so. You should consider buying one if you are going to be doing any real load development for the Luger.

Sieger

PS: Try those reduced charges.

[stefanosg]

I measured one of my loaded rounds and I get 1.152in . I am using 124g RN jacketed rounds with 3.7g of Bullseye. I've been fortunate and this recipe works in all my Lugers and my other 9mm handguns. I've got some WWII ammo and it is like you said a little longer at 1.164in .

[Sieger]

Originally posted by stefanosg
I measured one of my loaded rounds and I get 1.152in . I am using 124g RN jacketed rounds with 3.7g of Bullseye. I've been fortunate and this recipe works in all my Lugers and my other 9mm handguns. I've got some WWII ammo and it is like you said a little longer at 1.164in .

Hi Again:

You have hit on my old target load for the Luger, 3.7 grs of Bullseye with 124 grain FMJ bullets.

Your OAL sounds a bit too short to me. Can you shoot a full magazine of 8 rounds with this load without jamming? If you can, I never could. Also, the cartridges cant downwards at that length for me (too short). Look at a fully loaded magazine. The top cartridge should be at exactly the same angle as the bottom one, not canted downward. Look at how the body of the cartridge engages the lips of the magazine. It should be fully engaged, not canted downward ever so slightly.

The WWII German round nose was loaded at 1.169 inches, per my measurement and reference in several German texts. This length works with the shape bullet they were using. Other bullets won't function at this length because of the shape of the head of he bullet. That's why I start at 1.173 (probably maximum length, though I read a lot about 1.18 being considered maximum) and work down 0.001 at a time until the cartridges slip out of the magazine properly.

My best target group to date was with 3.7 grs of Bullseye: 8 rounds under the size of a quarter at 25 yards off the bench. The range master almost had a heart attack when I asked him to sign the target as witness. After all 9mm "aren't all that accurate"

Now for a challenge for you. The two best powders I have found to date for tight group Luger shooting, with perfect function are:

SR 4756 (IMR)
Power Pistol

These are medium slow powders, just like the powder used in the original DWM Luger cartridge. Power Pistol is also claimed to be the powder currently used by the Government in their modern 9mm Nato rounds.

Try some of this, using the work-up procedure I listed above. I think you will be shocked by the results and happy that you did.

Sieger

[Aaron]

I have no problems with my usual load of 4.5 gr. of 231. Have gone as high as 4.8 gr. with excellent results.

[Sieger]

Originally posted by Aaron
I have no problems with my usual load of 4.5 gr. of 231. Have gone as high as 4.8 gr. with excellent results.

Hi:

I've never loaded 231. If this load gives you perfect function and is accurate, go for it.

Sieger

[azlaw]

Armed with the sound advice of those here, I am pleased to report complete success. And the winner is:

115 gr FMJ, 4.5 gr W231, OAL 1.168" (+/- 0.002")

The byf 42 functions perfectly in the shop now; can't wait to get it out to the desert to shoot some common household objects, and maybe a few paper targets as well.

Interestingly, this load will not function in the Browning High Power - will not feed at all. A whole new mystery to sort out.

The Luger is certainly unlike any other pistol I have ever used. Very smooth in operation and firing, with a very good trigger. Quite unlike the Browning designs, I think because so much less mass is in motion to operate the action. I begin to see the attraction...

It is wonderful to have so much expert help available. Thanks!

H

[Sieger]

Originally posted by azlaw
Armed with the sound advice of those here, I am pleased to report complete success. And the winner is:

115 gr FMJ, 4.5 gr W231, OAL 1.168" (+/- 0.002")

The byf 42 functions perfectly in the shop now; can't wait to get it out to the desert to shoot some common household objects, and maybe a few paper targets as well.

Interestingly, this load will not function in the Browning High Power - will not feed at all. A whole new mystery to sort out.

The Luger is certainly unlike any other pistol I have ever used. Very smooth in operation and firing, with a very good trigger. Quite unlike the Browning designs, I think because so much less mass is in motion to operate the action. I begin to see the attraction...

It is wonderful to have so much expert help available. Thanks!

H

Hi:

It's all in the springs with the Luger design, as, you have noted, there isn't a whole lot of mass moving around. This is both a blessing and a curse. A blessing, as you have noted, in the feel of the pistol in action, a curse in the fact that the springs have to be in perfect "timing" for the pistol to function properly. Also, the Browning design lends its self to function with a much broader range of ammo without jams, etc.

With a Luger, the mag spring, recoil spring and ammo all have to to tuned for the pistol to function properly. If one of these is of spec., you will not get perfect function.

Think of it this way, the Luger is a Porsche, the Browning a Chevy. both will get you where you want to go, but are very different characters, indeed.

Sieger