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Education / Training HW 50S: Part 8

HW 50S: Part 8

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.

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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.

author avatar
Tom Gaylord (B.B. Pelletier)
Tom Gaylord, also known as B.B. Pelletier, provides expert insights to airgunners all over the world on behalf of Pyramyd AIR. He has earned the title The Godfather of Airguns™ for his contributions to the industry, spending many years with AirForce Airguns and starting magazines dedicated to the sport such as Airgun Illustrated.

41 thoughts on “HW 50S: Part 8”

  1. BB,

    With the addition of the washer I expected the forward jolt to have increased instead being reduced. I wonder how it will feel once it has been removed? Seems the way the piston fits also has a bearing on how this rifle behaves.


  2. Good morning, Siraniko, how goes your quest to find rubber mulch?

    B.B., under the heading, Cocking effort: “Now we will look at some things we didn’t look at yet because of the 25mm pistol [piston] seal thing.”

    What a cool rifle. Like the HW30S’s rebellious older brother.

    • Roamin Greco,

      Looking online as you said pulled some interesting hits but they were selling machines to make mulch out of tires. There is nobody locally using rubber mulch. Used tires are made into door mats and sandals. Looks like this is going to be a long term project if I’m going to make my own mulch. Not in a big hurry anyway since my target stuffed with old clothes still works for pellets.


      • Siraniko,

        The quest for rubber mulch has me wondering how to make the stuff at home.

        The lawnmower and the snowblower (briefly) crossed my mind but that definitely is a bad idea! LOL!

        Reciprocating saws and jigsaws would work. Reciprocating saws are a lot more powerful but the jigsaw would be more controlled and safer to use.

        They both have a variety of blade options, a bit of experimenting would be required to find the best solution. Speaking of solution, dish soap and water might be a good lubricant – something else to try.

        Think that avoiding the steel belts under the tread and the steel band in the tire’s bead would be best, the rubber on the side walls of the tire would be the easiest to harvest.

        Anyway, just speculating. I’m curious, if I get a chance I’ll try to dissecting a tire just to see how to go about it 🙂


        • Hank,

          I’m looking into it and I agree that the sidewalls would be the easiest to harvest. As to how I’m going to cut the tire into small chunks that’s going to be another thing. I don’t have a jigsaw or a reciprocating saw. I do have an angle grinder with a jig so I can use it as a 4 inch circular saw. Definitely going to be messy work. Still going to look into alternatives. Maybe an oscillating tool with a blade?


          • Siraniko,

            An angle grinder runs at 12 to15,000 rpm – ideal for grinding and cutting with an abrasive wheel but way too fast for a toothed blade. Considering that the rubber in a tire could easily “grab”, I think that any type of circular saw blade would be dangerous to use.

            A jigsaw or a reciprocating saw cuts by pulling the material against the base or shoe of the saw making it a “controlled” cut. Think they would be the best option if you could get a hold of one.

            Jigsaws are very handy and a 4 amp (or more), variable speed one is a versatile tool worth having. Just saying 🙂

            The low power and short stroke of an oscillating tool wouldn’t do well on a tire – would probably burn it out quickly.


          • Siraniko,

            I think any source of thick, tough rubber would work – truck mudflaps? Or maybe those door mats. I think the key thing is that when they’re cut into chunks, it’s much less likely for a pellet to impact square to a chunk of rubber, and the chunks can move in response, so you’re less likely to get a ricochet.


      • Cannot any of those companies spare a garbage bag full? It sounds to me like too much work and potentially dangerous work to tear up a tire with power tools. Perhaps tin snips might work better?

        Old rags are probably almost as good and you can still reclaim the lead.

      • I was able to find some but you either need to buy it wholesale by the ton or it is very expensive, but there are some companies that install it for playgrounds, perhaps they have some leftovers from a job that they can spare or provide a sample. Keep your eyes open and eventually you will find some, or like I suggested follow the trail of folks that sell and install a lot of tires. The used ones have to go somewhere. Here’s one site that may be interesting.
        GOOD LUCK!

        • Roamin Greco,

          Thanks for your efforts. It seems the safest method is to use a sharp blade or shears to cut the rubber to pieces. Locally there are a lot of used motorcycle and bicycle tires which I should be able to simply ask for if not buy cheaply. Since my regular target can is still recently refilled with old clothes it will take a while before I need to change it giving me time to make this project. I’ll update once I get around to it.


  3. B.B.

    It will be interesting to see if this rifle calms down even more.
    12 foot pounds is where you want to be. Any more is just unpleasant.

    PS if you have the JSB or AA 8.44 in 4.52 head size, it should shoot well.

  4. BB,

    I am not sure how that compares with the 30S in size, but I think once you take that washer out you will have a nice bigger brother for that 30S. A peep sight is most definitely recommended. I have a TruGlo front peep with a Williams rear peep on my grandson’s 30S right now. It is an awesome little shooter right now.

    Let’s see, you have the 30, the 50, the 80, the 95. Do you have the 35 and 90?

  5. Hello Everybody, I’m new on this wonderful blog. I would like to say hello from Germany! I’m actually made in Poland but since more then 19years living in Germany now. When I was little boy my Father bought Suhl300 airrifle and this was the beginning for me 🙂 Now, after few years without airgunning I’m back on the track again. Last year I quit smoking and all money goes for the toys now. Already spend 2.5kEUR which I did not just burned during last 13 months 🙂

    I really appreciate all work done and reporting. It is hard to find people with passion who just share it.

    My experience with diesel effect: if you have a detotanation-like events you should dismantle the system and clean it right away. Waiting until the grease or oil will burn out is not a good idea. I own also a HW50 and once, due to my mistake, I had a really bad detonation which broke the spring and destroyed the piston sealing.
    There is no point starting with chrono measurement if you can even smell burning grease. If it detonates – not at all… I’m pretty sure if you would clean the system and make a proper -grease finish again with only a silicone-oil film in the compression chamber the chrono results will be different.

    As example – today I will clean my brand new Cometa220 which came yesterday with down-powered spring. Unfortunately you can smell burning grease after each shot even when you can’t see smoke in the barrel. The chrono shows also some strange variation and of course the V0 energy is bigger than it supposed to be with this spring. Even if there is no smoke visible but you can smell diesel there will be influence on cinetic energy of the pellet. Sometimes big V0 variation is caused by “small diesel”. I will clean this new lady and give her stronger spring. But less grease is better then too much.
    After doing a proper work on tuning the system there should be no diesel smell after max 50 shots, not even mentioned the detonation events! Detonation is potentially a system killer (spring and piston sealing mostly).
    In general I would not start any chrono and accuracy test with tuned airgun directly. At least 100 shots to seatle the system stable is required before real test does make sense.

    • tomek,

      Welcome to the blog.

      The 50S is no longer detonating, so I’m going to leave it as is for now. I need to see how well it shoots.

      Thanks for your comments! Because of what you said I will discuss dieseling and detonation tomorrow,


      • Oh, thank you! I think the dieseling is a very important topic regarding spring powered airguns. Many people I know complained about poor results when shoting with good equipment. Even small dieseling amount may change the V0 delta pretty significant. This may be also additionally ambient temperature dependent. It may also be a trouble when there is energy limit restriction in your country by the law. It is very easy to get too much power when dieseling occurs even from a relative small powerplant.

        I killed my HW50 spring (broken) and seal with one big diesel event once 🙂 It was really loud, the H&N Silverpoint was definately over 1Mach fast. But only once it was so funny, then I had to replace the spring and the piston seal 🙂

      • BB, while you are on the subject of dieseling and detonation I would like your opinion on something that I read.

        We know that silicon ‘chamber’ oil will not detonate so it is recommended for the seals in spring guns and general high pressure PCP applications. It is well tolerated by practically all O-ring types.
        On the other hand it, silicon oil or grease are poor metal-to-metal lubricants.

        On the other extreme, any oil that contains distillates (?) – like penetrating oil – could detonate or diesel with even mild pressure, so there is agreement that they should be avoided.

        The article I mentioned said that high quality mineral oil (like Pellgun) or better yet pure synthetic oil (i.e. Mobil 1) shouldn’t cause problems and they are excellent lubricants.

        Based on youer experience, could you comment on this?


  6. Looking forward to the report on dieseling/detonation; FM knows there is a lot of information out there about the subject, but want to read the expert’s opinion about it, including the readership’s as well. After all, FM suffers from FOBS – Fear Of Breaking Something.

  7. BB

    Looking forward to tomorrow’s report on dieseling vs detonation. I admit to being surprised that you continued to shoot 15 or more detonations. But as you well know, some folks tried to soup up their guns via detonation.


  8. Tom, I was going through part 7 and didn’t notice if you had cleaned the main tube after removing the piston? The thin film left behind due to the undersized seal may be what caused the Big Bangs,,,,I have had that happen to me…

  9. BB
    I mentioned to Chris USA’s reply yesterday that I tryed one of the kits in a Tx 200 I had. It was better than the factory tune. But my tune on the Tx 200 was the best.

    Likewise with my new style stock hw50s. My tune is definitely better than the factory 50 tune. More calm to shoot. More accurate and easier to cock. Now I didn’t try one of the kits in my gun and for sure will not. My 50 just shoots to good to go there.

    • GF1 and BB,

      I would also like to hear about how you tuned your TX200, if you are willing to share that information.

      I also humbly remind BB that back on October 4th, in response to a question of mine, he said, “ I think a series on tuning the TX 200 Mark III is warranted.”

      As one of the many who bought the TX200 based on you thinking so highly of it, I would love to read a new series on tuning this fine airgun.

      I would be particularly interested in a tune that did not make use of a drop in kit.

      Thanks Guys. I look forward to reading any information you provide.


  10. I’m waiting to see what you do with the HW50. I have the PG3 in my HW50 and I would like to calm it down a little.

    I’d like to know how much of the spring on a PG4 to cut to make it 10 FPE.

    I only shoot 20 to 25 yards in my back yard.

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