Interesting findings of Walther LP53 and Lucznik

[clarky]

Being the owner of an LP53 already, I'm reading this with interest, although I don't intend any mods to mine. It comes out several times a year for light use, and always performs faultlessly. I've been tempted a few times to remove the end cap for a spring relube, but 'if it ain't broke, don't fix it' is always foremost in my mind.
In fact holding a FAC and fortunate enough in my location to have several S&W .22 lr revolvers & pistols, I can honestly say I get equal satisfaction whenever I bring out the Walther (for use at 10 meters), such is it's fine engineering, balance and excellent feel throughout the firing cycle. It's one of the few air pistols that I've been tempted to duplicate.

Its a good little shooter but major flawed (in comparison with modern springer design) for utilising 2 mainsprings one inside the other in attempt to pull out the most from its small internals. Basically the large outer spring is guided by the inner as a sudo guide rod but guide rods should be ultra smooth and not trying to twist or rippled with bound up coils. Hence the firing cycle is one of thud, twang bounce, when it only needs to be a thud.
I did achieve what I was seeking at the start of the post but did not relay anymore of my findings due to lack of interest in the thread.
I will however launch a topic on the airgun forum for anyone who is interested.

To be fair this site is more about springer tuning and PCP stuff, where pistols are a tiny side topic.

[eyebull]

Its a good little shooter but major flawed (in comparison with modern springer design) for utilising 2 mainsprings one inside the other in attempt to pull out the most from its small internals. Basically the large outer spring is guided by the inner as a sudo guide rod but guide rods should be ultra smooth and not trying to twist or rippled with bound up coils. Hence the firing cycle is one of thud, twang bounce, when it only needs to be a thud.
I did achieve what I was seeking at the start of the post but did not relay anymore of my findings due to lack of interest in the thread.
I will however launch a topic on the airgun forum for anyone who is interested.

To be fair this site is more about springer tuning and PCP stuff, where pistols are a tiny side topic.

I'm sure there would be some interest on the UBC.
I am very tempted to buy a predom now I have seen this thread and I know it can be made to shoot better. My LP53 is too nice to use all the time...one of the few airguns I am precious about

[deerwarden]

I.m really interested as I have always wanted one and now have one, I have a hobby lathe and will be interested in making delrin guide etc and doing the spring mod if it gets a bit more FPS and smoother action. deerwarden

[Josie & John]

Hi Clarky,

I would be interested in your findings. Bearing in mind the difficulties with piston access, would a 'half' tune consisting of a replacement mainspring and delrin guide be an easier option for those like me, who are mechanically challenged? It ought to smooth things up, if nothing else with the advantage of being instantly reversible.

Excellent thread and sensible advise -well done.

John

[clarky]

Hi Clarky,

I would be interested in your findings. Bearing in mind the difficulties with piston access, would a 'half' tune consisting of a replacement mainspring and delrin guide be an easier option for those like me, who are mechanically challenged? It ought to smooth things up, if nothing else with the advantage of being instantly reversible.

Excellent thread and sensible advise -well done.

John

Actually yes, indeed that's all I was able to do with the 53.
The first problem I had to consider is the initial performance. The Predom will edge the 53 from stock (if running as it should) but not by much.
Which puzzled me because it should be considerably better.
The reason for this is advantage's and disadvantages equalling each other out. The Predoms piston is much shorter, allowing more volume and stroke for more power potential but then hampered by being quite a bit lighter than the 53s. Given these guns have pistons which are far too light for the mainspring power, it virtually kills all the advantage of that extra volume/stroke.
Adding weight to the Predoms piston in the form a top hat brings about a big 35fps increase therefore.
In other words, if we can get both pistons weighing almost the same, the shorter length and greater stroke of the Predoms piston can then have the effect you would imagine.
Im going to shock you but with as much weight I could add and the P18 spring working on a Delrin guide rod saw the Predom almost manage 500fps with regular light match pellets.
This is why Konceptus have used the guide rod and piston weight down inside the piston....in the hope of getting the most weight in possible.

Now onto the 53. Here we cannot pack much inside due to the keyhole guide rod arrangement of the piston head unit but at least it does offer us some weight in an "as design" no need to modify component. With not too much gain to be had here, I decided to leave stock and simply add a steel slip ring washer of 2mm thick, which ended up being the weight of about a £1 coin.
The little short guide rod of the head unit also prevents adding the guide rod or piston weights at this end of course. So I simply installed the P18 spring but machined up a delrin guide to slip over the existing guide fixed at the grip cap end. You must do this of course because without the inner spring, the single large diameter P18 spring will rattle around on the 8mm diameter guide. The wall thickness of the guide isn't great but should be robust enough as there is no twisting force or leverage.
The result is very good. It means that the 53 is even better from the guide rod point of view, with the guide at the correct end and the piston guiding the front of the spring as is normal with tuned air rifles.
Results revealed that the 53 got the 450fps I was hoping for (low of 438fps to 456fps high) but easily the smoothest of the 2 guns.
Before anyone asks, this p18 spring of thicker Swedish wire does not allow the fitting of the std inner mainspring in an attempt to get even more power but it is virtually as powerful as the the 2 std springs together but the real bonus is that you can then correctly guide rod it so that all its potential is released smoothly.

Deeper tests have revealed the P18 with correct low friction guiding gives us 35 fps in both guns (roughly from std set up with duel springs)
The extra weight of the 2mm slip washer in the 53 (all I could get in without modification to the head unit) gave 9 fps
The extra weight of the big piston weight in the Predom gave 30fps
The extra stroke of the short Predom piston (once correctly weighted) gave 25fps

[Josie & John]

Thanks for the update Clarky,

Does your modification entail extra cocking effort and potential wear to the cocking lever/linkage? Also, with the increase in power, does the rearsight run out of adjustment at close distances of 6 yds or so?

It certainly sounds impressive.

Kind regards,

John

[clarky]

Thanks for the update Clarky,

Does your modification entail extra cocking effort and potential wear to the cocking lever/linkage? Also, with the increase in power, does the rearsight run out of adjustment at close distances of 6 yds or so?

It certainly sounds impressive.

Kind regards,

John

No cocking increase, or strain increase as the single mainspring has about the same strength of compression as the 2 stock springs, indeed perhaps very slightly less. However, all that power is released much more smoothly and with much improved efficiency meaning velocity does increase.
The 50fps to 100fps (gun dependant) did required 3 clicks down on the 53 elevation but did not run out of adjustment on either gun.
The gun seems to go off with a sharp fast thock, without the boing and twang when using 2 mainsprings