Interesting findings of Walther LP53 and Lucznik

[clarky]

Thank you so much for this information Clarky. I bought a rather battered 1954 LP53 last week, and was a bit disappointed with both the low velocity and the difficulty in shooting something like a group. It's certainly a jumpy pistol with the original springs - actually likely to have been replaced sometime in recent years, as they're both straight and show almost no wear. I thoroughly cleaned the pistol, lubed and assembled, and there was zero improvement in velocity - averaging 385fps with H&N Finale Match 7.56gr - and only a small reduction in firing harshness. So it was a relief to come across this thread!

Today I used part of a spring from an Industry Brand QB57 to try and replicate your findings. It was one I had already cut down to test in an IZH MP-61, but in that rifle it was too harsh, made accurate shooting impossible. I chopped the very open-wound spring down to just 16 turns in the end such that it fits loosely into the LP53, rattling a bit when assembled. Then I fitted a small stack of washers into the piston, 5.5mm deep and weighing 9 grams. The spring's OD was about 0.4mm larger than the original Walther spring so I mounted it on an aluminum rod and spun it against a sander, reducing by 0.3mm, then polishing on sandpapers and finally buffing until it matched the original spring and no longer made awful noises against the sear while cocking. Also made a delrin spring guide which is an easy fit into the spring as it is onto the original steel guide rod. All this resulted in a jump to about 425fps with the same pellets.

So I made a steel mushroom-shaped plug to fill about 1cm of the end of the new spring, drilling a hole in the far end to allow it to go over the pin in the piston head. Had to cut down the guide rods by about 1cm to allow cocking with this one in place - so this further weighting would not be likely with anyone wanting to keep the original features of the pistol intact. Mine's a beater, with lots of wear, a nastily messed up end cap thanks to idiots with pliers in decades past, and a hairline crack about 1/2 the way around the cast aluminum barrel shroud probably owing to someone using the thing as a hammer. The head of this filler of steel is about 5mm deep, similar to the washers I'd tried, but total added weight in the piston is 16 grams. Velocity went up to an average of 468fps with the 7.56gr pellets. No other pellet I have on hand goes as fast, with 7gr RWS pellets only doing about 448 to 455fps. Spread for ten shots with the heavier and slightly tighter fitting H&N went between 461fps and 475fps.

The result is a slightly quieter pistol, delivering 1.18fpe more power than it had when it came to me, and finally letting me group my pellets a bit more closely. It'll take practice with my grip to establish more horizontal control but the vertical has tightened up nicely with these changes. Cocking effort with this spring, which has about 1mm of preload when the cap touches the thread so perhaps 7mm preload when the cap is tightened, is about 3lbs more than stock. Still not too difficult. I don't need any sort of cocking aid with the pistol.

Thats a wonderful effort. Its not suprizing that the looks and firearm build quality of this pistol seem to encourage people to want to improve it like no other. Its nice to hear of someone else trying to restore and appreciate the well made things in life.
My masses of meddling experience with this gun recommends you to select sub 4.52 pellets..RWS R10 do this nicely at 4.49 and 4.50 across a broad sampling.
Try a very tight isocolese hold and you will realise the groups i achieve.
CHeck that breach seal too and leave your gun barrel broken when stored to preserve it.
You require an 8mm nitrile ring available from Knibbs for 3 quid.
I will send u a pic of my beautiful K version barrel chopped to the true bore and the foresight resoldered.
You can use BIrchwood Aluminium Black to perfectly restore any finish issues.....
Your hairline crack can be filled with Araldite 2031which is an epoxy but of black finish which perfectly matches the Birchwood finish i described.
Clean out all the moly.....its disasterous stuff esp with aluminium. The silicone content in it galls terrible.
Try Techniks LT2 paste especially on the front wall/ cocking slot where all the pressure is imparted.
Take a look at your piston washer. Bisley gun oil or vegetable oil a good restorer and keep it lightly oiled after a 24 hr soak.

I could probably get more out of one but ive decided to stand down now.
Its teasing me but im resisting. Im talking about the Powerpod piston weight. It has a hole through it unfortunately but required to accomodate the original spring guide that is fitted to the grip cap when the gun is cocked or it will not cock.
Thus slightly chopping this guide by 5mm or so would allow a solid weight and probably a 500 fps velocity.
However, i think i may now be at the limit of the machine. There is only so much one can get within the physical size constraints and i think we are about there already.
Thus leaving stock guide well alone .