HW 50S
The HW 50S breakbarrel from Weihrauch.

Part 1
Part 2
Part 3
Part 4
Part 5
Part 6
Part 7

This report covers:

  • Detonations
  • RWS Superdome
  • Air Arms Falcons
  • Crosman Premier 7.9-grain pellets
  • Firing behavior
  • Cocking effort
  • Trigger pull
  • Summary

Today we see how the Vortek PG4 SHO tune has affected the performance of the HW 50S breakbarrel air rifle. This is a direct follow-on from yesterday when we swapped the 25mm piston seal for the correct 26mm seal.

I will get right into the test. I shot the same pellets that were used in Part 2 to test the rifle in factory tune. It will be interesting to see the differences.


The first 15-20 shots after the swap were detonations. I had lubed the side of the new piston seal and that was apparently too much grease in the compression chamber. My advice to those who use this kit is don’t lubricate the piston seal.

When I started the velocity test I shot Air Arms Falcons at 1256 f.p.s. which is way out of profile for this rifle. So I switched to a heavier pellet to stop the detonations. Even so it took another several shots before the rifle quieted down.

RWS Superdome

The first pellet I tested for velocity was the 8.3-grain RWS Superdome. It was also the pellet I used to stop the detonations. The first two shots went out at 894 and 865 f.p.s., but shot number three was 817 f.p.s., so I started the string from there. These 10 shots  averaged 825 f.p.s. The low was 811 and the high was 838 f.p.s. — a difference of 27 f.p.s. At the average velocity the Superdome generated 12.55 foot pounds of energy at the muzzle. There’s your 12 foot pounds.

In the factory tune this pellet averaged 771 f.p.s. with a 15 f.p.s. spread. This was a significant increase.

Air Arms Falcons

Next up were 7.33-grain Falcons from Air Arms. Oddly the first two of these were recorded at 914 and 931 f.p.s. Then shot three went out at 1001 f.p.s., so I started the string with shot three. This string averaged 1000 f.p.s. The low was 973 and the high was 1056 f.p.s., for a difference of 83 f.p.s. At the average velocity Falcons generated 16.28 foot-pounds at the muzzle. That’s way over 12 foot-pounds, and in my opinion too hot for this light little rifle. I will say that one shot at 1056 f.p.s. was an anomaly because the next fastest shot was 1008 f.p.s.

With the factory mainspring and seal Falcons averaged 810 f.p.s. The spread was 32 f.p.s.

Crosman Premier 7.9-grain pellets

The final pellet I tested was the 7.9-grain Crosman Premier light that is no longer made. Ten Premier lights averaged  872 f.p.s. in the HW 50S. The low was 865 and the high was 882 f.p.s. — a difference of 17 f.p.s. At the average velocity the Premier light generated 13.34 foot-pounds — also a little too stiff for this rifle.

The factory spring and seal gave an average of 896 f.p.s. The spread there was 19 f.p.s. So I’d have to say that the 50S seems to like this pellet.

Shop Benjamin Rifles

Firing behavior

When the test began and the rifle was still detonating the rifle was jolting ahead pretty violently. At that point I vowed to remove the kit and replace the factory mainspring and seal if it didn’t calm down.

By the end of today’s test, which was a total of about 40 shots, including three detonating openers, the four shots I didn’t count and several that missed the second skyscreen, the rifle has become very calm and has only a fraction of the forward jolt that it started with. It’s a pleasant rifle to shoot, now that it has calmed down. I’m going to keep right on shooting it with this tune.

Cocking effort

Now we will look at some things we didn’t look at yet because of the 25mm piston seal thing. First is the cocking effort. The factory rifle cocked at 32 lbs. of effort. With the PG4 SHO tune installed it cocks with 37 lbs. of effort. I don’t like that at all. That’s what a Beeman R1 cocks at and it’s too much for a light little rifle like the 50S.

I will continue testing the rifle with it tuned the way it is now, but at some convenient time I will remove that washer I put in the piston. I could do with a lot less power and cocking effort.

Trigger pull

Okay, the trigger pull needs some reminding. In Part 2 I adjusted the trigger to break at 1 lb. 14 oz. In Part 5 when I tuned the rifle I adjusted the trigger again, but because of how the 25mm piston seal did in Part 6 I didn’t bother reporting the trigger pull. Well, now that the rifle is doing fine I can report on the trigger.

Stage one now takes 7.4 ounces to complete and stage two breaks at 14 ounces. The trigger is delightful and I plan to leave it right where it is.


Where does this leave us? Well, this HW 50S is shooting with far more power than I need. And it cocks with greater effort than I want to apply. At this point I wish I had bought the lower-powered kit instead of the SHO. Maybe with time that will change.

The shot cycle is quite smooth, but quick. The forward jolt is still there but it’s greatly reduced. It will be interesting to shoot this rifle for accuracy. I think I will do that next, and I’m thinking of mounting the peep sight.