HW/Weihrauch David and Goliath (HW25L .177 and HW80 .25)

[Wadcutter]

I really just wanted the HW80 with the .25 barrel, but impulse bid on the little tyke too. Ended up with both of them.

While cocking the 80 to test fire, it took extra effort to get it to latch, so I had a suspicion there was a spring kit in it. Also, there was some detonation when fired, so just shot it once. A little louder than a .22 short, and smoke filled the bore. Set that gun aside and test-fired the HW25L. OK...so this little thing is like a slice of pumpkin pie with Cool Whip. Sighted in at about 15yrds, not on paper, just center punching poplar leaves. LOL Hard to say, but this thing may replace the HW30 as the go-to backyard defender. The trigger is on the heavy side but breaks crisply. Not a fan of the fiber optic sights either, but other than that… a sweetheart.
Velocity test for the HW25L
JSB Exact RS .177.........7.33gr..............592fps..........5.71fpe

Stripped the HW80 and, sure enough, found a Vortek kit and two power washers installed, so that's a plus. Notice the grease on the front of the piston seal. That's the culprit causing the detonation. I ended up cleansing the tube with enamel reducer and removing one of the power washers. The piston fit a little tight in the bore, so also trimmed the seal OD while it was apart.

Initial results over chrony after reassembly_
Predator Polymag .25 ...........26gr............542fps.........16.96fpe
JSB Exact King .25 ...........25.39gr............539fps.........16.38fpe
Both these pellets and the JSB King Heavys fit unusually tight in the breech. Anyone else with a .25 notice that?

The numbers are lower than expected, but "wow," this thing sounds and feels like a force to be reckoned with. No sights yet, fresh out of scopes, just shooting into a tree stump at about 25 yards; sounds like a ball peen hammer smacking it.

Alternating between two springers on opposite ends of each spectrum is an interesting experience.
Guess I'll be looking for a good scope and mount.

 

[crowski]

Very nice. I have the k model which looks great but wish I had the longer barrel. I have the Vortek plus spring, one coil cut in it, too much but a JSB 25.?? 580 fps. Was my first Wiehrauch springer. The .25 wacks. Great gun. Enjoy. Crow

 

[Kgphotos]

.Set that gun aside and test-fired the HW25L. OK...so this little thing is like a slice of pumpkin pie with Cool Whip. Sighted in at about 15yrds, not on paper, just center punching poplar leaves.

I love your description of shooting the HW25. Paints the perfect picture of your experience. I’ve never tuned a springer. Out of curiosity how do you trim the seal for a better fit? Thanks,
Kenny

 

[Wadcutter]

Very nice. I have the k model which looks great but wish I had the longer barrel. I have the Vortek plus spring, one coil cut in it, too much but a JSB 25.?? 580 fps. Was my first Wiehrauch springer. The .25 wacks. Great gun. Enjoy. Crow

Thank you Crow. Yours is pushing up on 19fpe, which is closer to where I thought this gun should be, say 20fpe. Was thinking of shaving the seal down a bit more. but had "honey dos" to take care of so was in a hurry to get it back together. Besides, I read that the vortek seals sort of size themselves to the bore. Not sure I buy into that, but will put a couple tins thru it and revisit the chrony.

I love your description of shooting the HW25. Paints the perfect picture of your experience. I’ve never tuned a springer. Out of curiosity how do you trim the seal for a better fit? Thanks,
Kenny

I chuck the piston in a lathe and if it doesn't need much off, then just hold a sharp razor blade perpendicular to the seal and shave it down. Checking it often with calipers. If the seal is way oversized, then instead of a blade, start off using a Dremel tool and sanding drum pressed against the seal while its spinning in the lathe. Then finish off with the blade.
Keep in mind, I am not a tuner, just a collector who likes working my own airguns.

 

[Kgphotos]

Thanks Wadcutter. I appreciate that reply. I've never done a springer tune but I'm thinking of doing a slight de-tune of my HW50 this summer. I have watched a lot of videos for inspiration.
Kenny

 

[A.G.R]

Thank you Crow. Yours is pushing up on 19fpe, which is closer to where I thought this gun should be, say 20fpe. Was thinking of shaving the seal down a bit more. but had "honey dos" to take care of so was in a hurry to get it back together. Besides, I read that the vortek seals sort of size themselves to the bore. Not sure I buy into that, but will put a couple tins thru it and revisit the chrony.


I chuck the piston in a lathe and if it doesn't need much off, then just hold a sharp razor blade perpendicular to the seal and shave it down. Checking it often with calipers. If the seal is way oversized, then instead of a blade, start off using a Dremel tool and sanding drum pressed against the seal while its spinning in the lathe. Then finish off with the blade.
Keep in mind, I am not a tuner, just a collector who likes working my own airguns.

To get the most out of a .25 with a 80 mm stroke you will need to check the port and take it to at least 3.5 mm and don’t go with a loose seal. They like some back psi. Tuning for power and smoothness for the power is a ballance as you can’t beat Newtons laws. That is the older kit and is decent but harder to cock. Big .148 white with smallish .860 od ,It’s a bit heavy spring for what you get. The .905 spring is easier. And can do the same, with the right set up. The best option is the new Macarri At kit with the 30 coil spring , I would change the delrin top hat to steel for more weight and load for .25 20 grain domes will net better yields also as it’s a short stroke gun.

I am building a custom 90 mm stroked R1 in .25 now with a custom piston and such. .24 /25 ft lbs is the goal goal.
as well as a custom monster 32 ft lb gun with a rekord trigger and custom action 118 mm stroke.
I do say I like the .25. And have built a few up to 35 ft lbs.

 

[beerthief]

And then their is ME ! I consider 14 FPE high power . loopy shot with .25

 

[Wadcutter]

To get the most out of a .25 with a 80 mm stroke you will need to check the port and take it to at least 3.5 mm and don’t go with a loose seal. They like some back psi. Tuning for power and smoothness for the power is a ballance as you can’t beat Newtons laws. That is the older kit and is decent but harder to cock. Big .148 white with smallish .860 od ,It’s a bit heavy spring for what you get. The .905 spring is easier. And can do the same, with the right set up. The best option is the new Macarri At kit with the 30 coil spring , I would change the delrin top hat to steel for more weight and load for .25 20 grain domes will net better yields also as it’s a short stroke gun.

I am building a custom 90 mm stroked R1 in .25 now with a custom piston and such. .24 /25 ft lbs is the goal goal.
as well as a custom monster 32 ft lb gun with a rekord trigger and custom action 118 mm stroke.
I do say I like the .25. And have built a few up to 35 ft lbs.

Thank you, That's great advice and will have to check the tp.
Yea, I have the 905148 vortek spring in another R1 and it's noticeably easier to cock.

 

[Mycapt65]

I read that the vortek seals sort of size themselves to the bore. Not sure I buy into that

That's an older Vortek kit and seal. It predates when I started using them in 2016. The Vortek seals that size themselves are black.

 

[Mycapt65]

Looks like there's metal shavings inbedded in the piston seal face and perimeter. What's the cylinder walls look like?

 

[Wadcutter]

That's an older Vortek kit and seal. It predates when I started using them in 2016. The Vortek seals that size themselves are black.

I wondered about that after looking on their website and seeing the newer ones were black, but now after reading A.G.R's post about back pressure on the .25, it may be about right after shaving it down a bit. Still had to push the piston in using the spring, but didn't feel overly tight as before. I don't plan on shaving any more off of it for now. I shot a half tin through it today with open sights; spares from an RX2 I believe. After a couple thousand rounds, I'll chrony it again and see where we're at. If there's not a big improvement, then will take a close look at the transfer port diameter. My guess is that's some of the issue.

Looks like there's metal shavings inbedded in the piston seal face and perimeter. What's the cylinder walls look like?

There was no visible damage to the cylinder walls other than some light etching. I also ran a hone down it. There were a few irregularities around the cocking slot, so filed them smooth, but nothing looked out of the ordinary. In a nutshell, I really don't know what the shavings were from, other than maybe where I'd sat the piston, seal side down, on the wooden work board shown in the picture. It very well could have picked up some of the metal shavings left after drilling through a nickel plated tube earlier. I do know that none were embedded in the seal, because I wiped it down with reducer and inspected it closely for defects.

 

[Wadcutter]

And then their is ME ! I consider 14 FPE high power . loopy shot with .25

Did some more break-in/experimental plinking with Goliath. With the iron sights at maximum elevation, it's dead on at twenty yards and drops about eight inches at 36 yards. So yea, this .25 springer is as you describe, "loopy." Definitely not a gun for open sights.
Re-checked the velocity after 500 rounds and discovered the improvement was negligible. Before wasting any more pellets, I decided to go ahead, take the barrel loose, and measure the transfer port. Surprise, it was only 2.95MM. Earlier A.G.R. recommended a minimum of 3.5MM for .25 caliber, so opening up the port, to see what a difference it makes, should be an interesting experiment.