Erfurt LP08 Sights Need Attention

[jmoore]

I have an artillery model Erfurt with the "Fine Tunable" sights which are not wanting to move. Got the screws to turn a bit, but so far no shifting of the rear sight blade nor of the front sight.


Had the rear sight off recently to repair the notches for the slider and soaked it for a while in PB Blaster. Otherwise, nothing further done until I get more educated!


Did take out and try it "as is" in a recent IHMSA Big Bore competition. Not a spectacular success as I needed to hold well off target to connect!


Anybody know the ins and outs of this system?

---------- Post added at 04:24 AM ---------- Previous post was at 04:18 AM ----------





The dovetailed area is quite immovable so far! Same for the front sight blade. Afraid to force the issue as spares don't litter the countryside.



Had to get the lower notches welded. Then the fun began. This area is now sorted.

Information

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[Peter Laidler]

Nice work JM. A pleasure to see. You obviously trusted your friendly tig welder!

[jmoore]

Nice work JM. A pleasure to see. You obviously trusted your friendly tig welder!

Laser weld, in actual fact! Man specializes in micro-welding. The photo above shows it "as is" after the weld. No discoloration, warping, or undercuts. Beauty.


The "fun" was generating a cutter smaller than 0.035" thick. I ended up dressing down a tiny grinding wheel to 0.025" so as to have some "wiggle room" whilst bringing the notches back to size in the mill.


All of which is incidental to the actual purpose of this thread: The dovetailed portions of the front and rear sights are still stuck! And I haven't the least bit of experience with these sights. Trying not to get in a rush and destroy anything, however, I bought it to shoot and it doesn't yet hit where it looks.



50m Chickens, 100m Pigs



150m Turkeys (tried both 200m and 100m sight settings), and 200m Rams


As can be seen on the spotting sheets, it seems a reasonably precise pistol, just not zeroed.

[browningautorifle]

Then the fun began.

Needle files on a hard nut of weld I'm thinking? Extra glasses and no Scotch until finished.

[Peter Laidler]

If it was me pondering this JM, I'd be thinking along these lines. But bear in mind I don't know zilch about your particular sights! But the presence of lines indicating a dovetail AND a locking mech tells me that the part was made to a) move and b) be locked afterwards. And together that indicates that there's not a screw thread type adjuster there. I would heat the female part of the dovetail, clamp it and use a brass drift to judiciously start movement of the male part.

[jmoore]

...But the presence of lines indicating a dovetail AND a locking mech tells me that the part was made to a) move and b) be locked afterwards. And together that indicates that there's not a screw thread type adjuster there....

Had not considered the screws to be merely locking devices! Interesting.... Wouldn't do for sight changes under time pressure, but at least it suffices for establishing a useful starting point. Which would be fine. Not expecting to shoot perfect scores with this pistol, but it's fun, and none of the other IHMSA shooters recalls anybody else trying their hand with such an "antique".

[MSW2]

Not expecting to shoot perfect scores with this pistol, but it's fun, and none of the other IHMSA shooters recalls anybody else trying their hand with such an "antique".

Would love to get my hands on an "antique" like yours. Just not sure if IMSSU rules for the items I participate in would allow a barrel of that length. Would be nice though

[jmoore]

... Just not sure if IMSSU rules for the items I participate in would allow a barrel of that length. Would be nice though

It's an 8" barrel, so it easily makes "Production" class in both Big Bore and Field Pistol (10 3/4" max length for both). No 150m sight setting, but hoping to be able to use the 200m setting and hold on the foot or thereabouts on BB Turkeys.


Whether it will reliably knock down 25kg 200m Rams remains to be seen. Our BB range has the targets calibrated to minimum topple force standards, so hopefully not TOO many "ringers"! Assuming I can hit them, of course!

[Patrick Chadwick]

... Whether it will reliably knock down 25kg 200m Rams remains to be seen.

A word of caution: much modern ammunition is simply to hot for the old knee-joint mechanism on a P08 or LP08. It hammers the cam profile and eventually peens it out of shape. If you can find it, use a load that produces a muzzle velocity of not much more than 320 meters/sec with a 124/125 gn bullet. Lapua produced such a cartridge, but it now seems to be unobtainable. If you value your antique (and I know you do) please do not be tempted to use a stronger load just to be able to knock over a piece of iron plate!

[Patrick Chadwick]

"All of which is incidental to the actual purpose of this thread".

Not for me! As I have one of these beasts - LP08, that is, not chickens - with a tatty backsight. I am grateful to you for the photo of the welded notches.
It seems to be a bit of a systematic weakness with these sights that the rearmost notches go "kaputt".
Now I can show a welder exactly what I need done on my example.

Coming back to your problem with the frozen sights. It may simply be oil/grease that has become extremely fossilized. I have had foresight parts that needed a brass drift to separate them, as the old grease had turned into something like a resin. A substance upon which penetrating oils had no effect.

But before applying heat (which is a good suggestion, BTW, but watch out for any bluing) try soaking the part in acetone overnight. If that doesn't soften up any ancient gunge, then use heat - but dry off the acetone beforehand!