HW95 .25 tune results

[Teber66]

After watching several videos on disassembling a HW95 and with a few emails to the gentleman that tuned my HW97 I decided to do my 95 myself. I stripped it down and cleaned all the factory grease off and out of it, put a plateau finish on the piston using 400 grit wet dry, fitted a Hornet piston seal from Maccari. Used one of his adjustable tune kits but only utilized his spring, top hat and preload washers. Used the factory spring guide and installed a needle bearing between it and the spring. Lightly lubed the piston and the guide and spring. Using three preload washers is getting me the results as seen below. After putting it together I cocked it and let it sit for 40 minutes to help speed up the break in. I put around 200 pellets through it before shooting it over the chronograph and shooting for groups.

all groups are 5 shots at 20yds. Hopefully in the next week or so the winds will calm down and I’ll stretch it out further.



Predator GTO 16.54gr

HI 597

Lo 582

Avg 588

SD 4.988

ES 15

ftp’s 12.7

Baracuda Green 19.91gr

Hi 546

Lo 530

Avg 537

SD 4.822

ES 16

FTP’s 12.75

The shot cycle with the 19.91gr pellets is really nice and smooth.

 

[Moog]

Those look like very good groups and it was interesting to see the velocities that you got. I've always been curious about the HW95 in .25 caliber because I have two HW95 rifles in .22. I also installed Maccari springs and Hornet piston seals in my HW95's and stayed with the factory spring guides too. I've been very pleased with the results.

 

[Mycapt65]

Accuracy looks good! Congrats on doing it yourself. 

 

[GoldenStateAIRGUNer]

What were the velocities before the tune ?

 

[Teber66]

What were the velocities before the tune ?

These chrono numbers are from when it was fairly new and completely stock. I’ve got another piston seal to try in it because I’m not sure how good of a job I did fitting the Hornet seal to it. It was fairly oversized when I got it. 

 

[ChuckHunter]

Those hornet seals are pretty stiff and require an almost perfect tube to get good performance!

They do take a little time and plenty of shooting to break in completely too... Those Maccari springs are usually a little under factory power too...but are smoother cocking and last much longer! 

I'm curious about the needle bearing thing??? Any pics on that set up?

Oh yeah looks like a winner in accuracy department

 

[Deerstalker]

Excellent piston seal for the HW95. http://vortekproducts.com/ourstore/Airgun_piston_breech-seals/Vac-SEAL26

Chrono #s after ARH kit with Vortek seal & GPL-205 lube on HW95L .22.

Created: 12/31/21 12:07 PM

Description: H&N FTT 14.66 gr 5.53

Notes 1: Partly cloudy

Notes 2: Very accurate at 25 yards, 1”

Distance to Chrono(FT): 4.00

Ballistic Coefficient: 0.021

Pellet Weight(gr): 14.66 FTT

Temp: 64 °F

BP: 1016.00 inHg

Altitude: 495 Cary, NC

# FPS FT-LBS

10 715 16.65

9 714 16.60

8 717 16.74

7 715 16.65

6 717 16.74

5 714 16.60

4 722 16.97

3 717 16.74

2 712 16.51

1 708 16.32

Average: 715.1 FPS

SD: 3.7 FPS

Min: 708 FPS

Max: 722 FPS

Spread: 14 FPS

True MV: 715 FPS

Group Size (in): 1” @ 25 yards

 

[GoldenStateAIRGUNer]

What were the velocities before the tune ?

These chrono numbers are from when it was fairly new and completely stock. I’ve got another piston seal to try in it because I’m not sure how good of a job I did fitting the Hornet seal to it. It was fairly oversized when I got it. 

Well based on those chrony numbers I'd say you picked up quite a bit power ! Might be burning off some excessive lube right now so it will be interesting to see how much that velocity drops off.

 

[Teber66]

What were the velocities before the tune ?

These chrono numbers are from when it was fairly new and completely stock. I’ve got another piston seal to try in it because I’m not sure how good of a job I did fitting the Hornet seal to it. It was fairly oversized when I got it. 

Well based on those chrony numbers I'd say you picked up quite a bit power ! Might be burning off some excessive lube right now so it will be interesting to see how much that velocity drops off.

Those are pretune numbers. 

 

[GoldenStateAIRGUNer]

What were the velocities before the tune ?

These chrono numbers are from when it was fairly new and completely stock. I’ve got another piston seal to try in it because I’m not sure how good of a job I did fitting the Hornet seal to it. It was fairly oversized when I got it. 

Well based on those chrony numbers I'd say you picked up quite a bit power ! Might be burning off some excessive lube right now so it will be interesting to see how much that velocity drops off.

Those are pretune numbers.

Then I'm somewhat confused. You list two different chronograph results. The second shows a increase of 100 fps with the GTO pellet. So your second post showing that 100 fps increase was also pretune ?? How do you account for that increase in a untuned rifle ? Like I mentioned, it sounds like your saying BOTH of those chrony numbers you posted were pretune.

 

[Teber66]

What were the velocities before the tune ?

These chrono numbers are from when it was fairly new and completely stock. I’ve got another piston seal to try in it because I’m not sure how good of a job I did fitting the Hornet seal to it. It was fairly oversized when I got it. 

Well based on those chrony numbers I'd say you picked up quite a bit power ! Might be burning off some excessive lube right now so it will be interesting to see how much that velocity drops off.

Those are pretune numbers.

Then I'm somewhat confused. You list two different chronograph results. The second shows a increase of 100 fps with the GTO pellet. So your second post showing that 100 fps increase was also pretune ?? How do you account for that increase in a untuned rifle ? Like I mentioned, it sounds like your saying BOTH of those chrony numbers you posted were pretune.

Stock configuration: pre tuning.

JSB Predator GTO 16.54gr

Hi 685 FPS 

Lo. 680 FPS

Avg 682 FPS

SD 1.62

ES 5 FPS

Foot Pounds 17



H&N Baracuda Green 19.91gr

Hi 615 FPS

Lo 601 FPS

Avg 607 FPS

SD 4.63

ES 14 FPS

Foot Pounds 16



post tuning results 

Predator GTO 16.54gr

HI 597

Lo 582

Avg 588

SD 4.988

ES 15

ftp’s 12.7

Baracuda Green 19.91gr

Hi 546

Lo 530

Avg 537

SD 4.822

ES 16

FTP’s 12.75

 

[GoldenStateAIRGUNer]

Gotcha! So you actually lost almost 100 fps with the tune !! Something not right. 

 

[Teber66]

This setup doesn’t have the Maccari bottom spring guide with the preload built in. Still have some playing around with it and different tunes. Would like to get it around the 13-14 ftp range. I’ll play with it some more today. Might even cut a few coils off the factory spring and try it that way.