Damage to breechblock around extractor

gwbeyer · 07-12-2016, 12:09 PM

I have discovered some damage to the breechblock near the extractor after firing my Luger. The damage is seen at the front of the breechblock on either side of the extractor. There are travel limiting lips built into the breechblock that will allow the extractor to only raise so far. The metal has apparently been hammered by the extractor and raised upward. I'm a little surprised that the extractor would be raised with such force during cycling...

A little history: I have had this pistol a long time and it had been reblued at least once before I got it. I subsequently polished, then rust blued the entire bolt assembly after replacing the rear toggle, which had cracked.

Suspecting too much material had been removed in refinishing, I made some measurements and compared them to those on the Luger Blueprints DVD I purchased years ago. The drawing shows the measurement of these limit lips to be 1.3 mm (.051") top to bottom. On my Luger they measure about .035". I cannot read German well enough to determine the tolerance on this spec.

FYI, my load is 4.5 gr. of VV N350 behind the 124 grain RCBS 9MM-124-RN bullet in wheelweight alloy. This load cycles beautifully.

So, what's the verdict from those of you that may have seen this in the past? Do I start looking for a numbers matching (33) DWM breechblock, or is there something more involved going on here?

Gary

John Sabato · 07-12-2016, 01:34 PM

As you can see in this blueprint extract (Image 1), The area you describe is dimensioned as 1.3mm. it is the only dimension I see on this blueprint that is this value.

From the blueprint table the tolerance for this dimension is 0.1mm, (which was corrected from the previous tolerance of 0.05mm (image 2) which has been crossed out.)

0.1 millimeters is 0.003937 inches.
0.05mm is 0.0019685 inches.

I think that you have correctly diagnosed your problem as the extractor stops are excessively worn by constant hammering of the firing cycle (after being reduced in size by material removal during refinishing).

this gun is obviously a shooter class gun, so I wouldn't waste any time trying to find a DWM breechblock with a matching serial number... just get a replacement block and fit it to the gun and have fun shooting it.

If retaining matching numbers is important to you, then have the area of the original breechblock micro-welded and then remachined to the blueprint. But this will Not be cost effective in my opinion.

Dick Herman · 07-12-2016, 01:59 PM

This problem has been seen before and discussed in depth recently in this forum.

DonVoigt · 07-12-2016, 10:58 PM

Cracked rear toggle and hammered breech block - must have been abused or shot a tremendous amount in its history.

I agree, just buy a new mfg, or a used good condition BB and move on!

If 4.5 gr of VV340 functions your luger well, I'd also suspect the main spring is weak.
Perhaps you should consider changing it, that could have contributed to your problems.

Check the inside back of the frame also for hammering.

Karl · 07-13-2016, 09:18 AM

I concur with Don's assessment. The fact that the rear toggle also previously cracked may be significant. The recoil spring may be too weak. I suggest that you get the Wolff mainspring kit with three progressively lighter springs and use the heaviest spring that allows the gun to cycle.
KFS

07-12-2016, 12:09 PM	#1
gwbeyer New User Join Date: Mar 2013 Posts: 2 Thanks: 0 Thanked 0 Times in 0 Posts	Damage to breechblock around extractor I have discovered some damage to the breechblock near the extractor after firing my Luger. The damage is seen at the front of the breechblock on either side of the extractor. There are travel limiting lips built into the breechblock that will allow the extractor to only raise so far. The metal has apparently been hammered by the extractor and raised upward. I'm a little surprised that the extractor would be raised with such force during cycling... A little history: I have had this pistol a long time and it had been reblued at least once before I got it. I subsequently polished, then rust blued the entire bolt assembly after replacing the rear toggle, which had cracked. Suspecting too much material had been removed in refinishing, I made some measurements and compared them to those on the Luger Blueprints DVD I purchased years ago. The drawing shows the measurement of these limit lips to be 1.3 mm (.051") top to bottom. On my Luger they measure about .035". I cannot read German well enough to determine the tolerance on this spec. FYI, my load is 4.5 gr. of VV N350 behind the 124 grain RCBS 9MM-124-RN bullet in wheelweight alloy. This load cycles beautifully. So, what's the verdict from those of you that may have seen this in the past? Do I start looking for a numbers matching (33) DWM breechblock, or is there something more involved going on here? Gary __________________ Beyer Firearm Restoration and Repair

07-12-2016, 01:34 PM	#2
John Sabato Lifer Lifetime Forum Patron Join Date: Jun 2002 Location: The Capital of the Free World Posts: 10,153 Thanks: 3,003 Thanked 2,304 Times in 1,096 Posts	As you can see in this blueprint extract (Image 1), The area you describe is dimensioned as 1.3mm. it is the only dimension I see on this blueprint that is this value. From the blueprint table the tolerance for this dimension is 0.1mm, (which was corrected from the previous tolerance of 0.05mm (image 2) which has been crossed out.) 0.1 millimeters is 0.003937 inches. 0.05mm is 0.0019685 inches. I think that you have correctly diagnosed your problem as the extractor stops are excessively worn by constant hammering of the firing cycle (after being reduced in size by material removal during refinishing). this gun is obviously a shooter class gun, so I wouldn't waste any time trying to find a DWM breechblock with a matching serial number... just get a replacement block and fit it to the gun and have fun shooting it. If retaining matching numbers is important to you, then have the area of the original breechblock micro-welded and then remachined to the blueprint. But this will Not be cost effective in my opinion. Attached Thumbnails __________________ regards, -John S "...We hold these truths to be self-evident that ALL men are created EQUAL *and are endowed by their Creator* with certain UNALIENABLE* rights, and among these are life, LIBERTY, and the pursuit of happiness..."*

07-12-2016, 10:58 PM	#4
DonVoigt User Join Date: Apr 2015 Location: near Charlotte NC Posts: 4,681 Thanks: 1,441 Thanked 4,350 Times in 2,040 Posts	Cracked rear toggle and hammered breech block - must have been abused or shot a tremendous amount in its history. I agree, just buy a new mfg, or a used good condition BB and move on! If 4.5 gr of VV340 functions your luger well, I'd also suspect the main spring is weak. Perhaps you should consider changing it, that could have contributed to your problems. Check the inside back of the frame also for hammering. __________________ 03man(Don Voigt); Luger student and collector. Looking for DWM side plate: 69 ; Dreyse 1907 pistol K.S. Gendarmerie

07-12-2016, 01:59 PM	#3
Dick Herman User Join Date: Apr 2006 Location: Texas Posts: 302 Thanks: 496 Thanked 354 Times in 138 Posts	This problem has been seen before and discussed in depth recently in this forum.

07-13-2016, 09:18 AM	#5
Karl Lifer - Twice Over Lifetime Forum Patron Join Date: Jun 2002 Location: Savannah Posts: 520 Thanks: 0 Thanked 266 Times in 116 Posts	I concur with Don's assessment. The fact that the rear toggle also previously cracked may be significant. The recoil spring may be too weak. I suggest that you get the Wolff mainspring kit with three progressively lighter springs and use the heaviest spring that allows the gun to cycle. KFS