Need help with .30 bullet selection

[CptCurl]

All shooting was done with my DWM 1923 Commercial shooter, #7762 l. It is in excellent condition with a 98mm barrel and fine bore. On this forum it would be called an Alphabet Commercial (or something of the sort).

My first thought was to try to capture one of the fired bullets. I filled 8 one gallon milk jugs with water, lined them up and shot. The bullet went through all eight jugs of water and kept going, so all I got from that endeavor was a mess.

I fired 18 more rounds for accuracy and function. Accuracy was so-so; not acceptable from what I have seen with this pistol.

Function was also so-so. There were no failures to eject. There were two failures to fully feed. In those instances the cartridge entered the chamber, but not fully. I think I know why.

The action held open on the last shot every time it was supposed to do so.

I believe my OAL was too long, and that this caused the two failures to fully feed. It appeared to be binding slightly as the cartridge made the corner around the feed ramp going into the chamber. In my next tryout loads I will reduce the OAL to 1.115"

The load shot clean. There was no lead residue in the bore. Powder residue wiped out with a patch and solvent.

I believe with more tinkering a good load will be found. More reports as facts develop.

Curl

[Sieger]

Originally Posted by CptCurl

I believe my OAL was too long, and that this caused the two failures to fully feed. It appeared to be binding slightly as the cartridge made the corner around the feed ramp going into the chamber. In my next tryout loads I will reduce the OAL to 1.115" Curl

Curl,

The two jams you describe above sound like the typical, annoying "Luger Jam".

Cartridge O.A.L. is critical for positive action function. Your tests for proper O.A.L. should be done before you go the range. For a good explanation of how to determine proper O.A.L., for a new bullet type, please see my thread on "Determining Proper Cartridge O.A.L." in this section of the site. I bet your O.A.L. is too short, but you won't know until you have gone through the pre-firing development stage, then the range test. The original O.A.L.s, of both the 9mm and 7.65mm DWM truncated cone bullets, were right at 1.14 inches (29mm). I have noted that the wider the "flat" on the nose of the bullet, the shorter the proper O.A.L. for proper function. Remembering that the original DWM "flat" was 4mm, you might want to measure the "flat" on your subject bullet. If I were testing, I'd start at 1.15 inches and work down .01 inch at a time until I found perfect function.

Once you have determined the proper O.A.L., for the bullet you are testing, then you are free to move on to the charge development stage. Again, I'd start at about 4.8 grains, or so, of your SR 4756 and work up 0.1 of a grain, at a time, until you get perfect action function and accuracy. Accuracy, for me, is three out of three touching at 25 yards, shot over sand bags.

When the action starts working (with proper hold open) and the groups start tightening, then you are in the range to develop a great load.

I'd be interested in seeing the necks of your fired cases. Do the necks show any pressure signs; for instance, chamber milling marks engraved into the brass?

By the way, your initial load shot through eight one gallon milk jugs?!?. If you would test again, after you are comfortable with your load, I'd really be interested in seeing just how many jugs it takes to actually stop your bullet.

Sieger

[CptCurl]

Originally Posted by Sieger

Curl,

The two jams you describe above sound like the typical, annoying "Luger Jam".

Cartridge O.A.L. is critical for positive action function. Your tests for proper O.A.L. should be done before you go the range. For a good explanation of how to determine proper O.A.L., for a new bullet type, please see my thread on "Determining Proper Cartridge O.A.L." in this section of the site. I bet your O.A.L. is too short, but you won't know until you have gone through the pre-firing development stage, then the range test. The original O.A.L.s, of both the 9mm and 7.65mm DWM truncated cone bullets, were right at 1.14 inches (29mm). I have noted that the wider the "flat" on the nose of the bullet, the shorter the proper O.A.L. for proper function. Remembering that the original DWM "flat" was 4mm, you might want to measure the "flat" on your subject bullet. If I were testing, I'd start at 1.15 inches and work down .01 inch at a time until I found perfect function.

Once you have determined the proper O.A.L., for the bullet you are testing, then you are free to move on to the charge development stage. Again, I'd start at about 4.8 grains or so and work up 0.1 of a grain, at a time, until you get perfect action function and accuracy. Accuracy, for me, is three out of three touching at 25 yards, shot off of sand bags.

When the action starts working (with proper hold open) and the groups start tightening, then you are in the range to develop a great load.

I'd be interested in seeing the necks of your fired cases. Do the necks show any pressure signs; for instance, chamber milling marks engraved into the brass?

By the way, your initial load shot through eight one gallon milk jugs?!?. If you would test again, after you are comfortable with your load, I'd really be interested in seeing just how many jugs it takes to actually stop your bullet.

Sieger

Sieger,

I took your advice and lengthened my OAL rather than shorten it. I loaded a batch with the bullet seated for exactly 29mm OAL. I changed nothing else.

The first issue I faced was with the magazine that accompanies my DWM 1920 Commercial "shooter". It's an after-market magazine, brand unknown. Dimensionally it is too short (front to back) to accommodate rounds at 29mm OAL. I can place seven rounds of these longer rounds in this magazine, but it will not accept the eighth round. So I tried an original DWM magazine. They fit perfectly. Also with a WW2 military magazine. Therefore, I did my shooting this afternoon using these two magazines and not the after-market one.

The pistol functioned flawlessly over two full magazines.

Accuracy was somewhat disappointing, but I must confess my less than stellar ability with the Luger's spongy trigger pull.

You were certainly spot-on as to OAL.

More later.

Curl

[Sieger]

Originally Posted by CptCurl

Sieger,

I took your advice and lengthened my OAL rather than shorten it. I loaded a batch with the bullet seated for exactly 29mm OAL. I changed nothing else.

The first issue I faced was with the magazine that accompanies my DWM 1920 Commercial "shooter". It's an after-market magazine, brand unknown. Dimensionally it is too short (front to back) to accommodate rounds at 29mm OAL. I can place seven rounds of these longer rounds in this magazine, but it will not accept the eighth round. So I tried an original DWM magazine. They fit perfectly. Also with a WW2 military magazine. Therefore, I did my shooting this afternoon using these two magazines and not the after-market one.

The pistol functioned flawlessly over two full magazines.

Accuracy was somewhat disappointing, but I must confess my less than stellar ability with the Luger's spongy trigger pull.

You were certainly spot-on as to OAL.

More later.

Curl

Curl,

Your 1923 Commercial should have one of the better Luger triggers, as my 1920 Commercial has a really great one!

The "pull" of the Luger trigger is somewhat similar to the Mauser rifle triggers of the same period. It is a "double pull" trigger; that is, there is quite a bit of slack to be taken up before you reach the "solid" part of the pull. On my 1920's trigger, the slack is somewhat reduced over what I've typically experienced with a military 9mm Luger.

After you have taken up the slack, then you have to address the actual "breaking point" of the trigger. Here is how I have mastered it. With the tip of your index trigger finger, place it as low as possible on the trigger, while aligning the trigger in the middle of the top digit of your trigger finger. Do not touch the trigger or trigger guard with any other part of your trigger finger. Load up some primed only casings and practice your trigger pull. It takes just a bit of training, once you have examined how the trigger "breaks" and have adjusted your pull accordingly. If your pistol is a true "shooter" you may also want to give your sear and firing pin contact points a good polishing, as this will aid in smoothing up your "breaking point".

One note on reliable Luger function. With proper springs, both magazine and recoil, proper cartridge O.A.L. and proper powder type and charge, a Luger will function flawlessly. With my handloads, my 1941 byf has fired over 3,000 rounds with no malfunctions, whatsoever.

Hope this helps!

Sieger

P.S.: It's the last 1/10th of a grain that makes all of the difference!!!