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Discussion Starter · #1 ·
Hello everybody,
as some already know I am a player from Italy, with a limit of 1 Joule for all weapons.
I'm finishing building my VSR-10 WELL.

I see online that many have a cone-shaped cylinder head accompanied by an air brake, while mine is flat and has no air brake (see photo, it's the original well one).
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From what I understand, it is made to have a better air compression and therefore to gain power. (Right?)

But I tried to do an air seal test, and when I keep my finger pressed on the cylinder head so as not to let the air out, after loading the piston, the latter remains completely still, so it means that there is none air leakage, and consequently I can say that I have a perfect air seal.

Now, do I really need to have the inside of the cylinder head in a conical shape or not? (considering my limit is 1JOULE and my air seal is perfect)?
If yes, why?
Thank you.
 

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Short answer: No, not needed and will not offer any significant accuracy increase.

Longer answer: What tapering and boring out the head of your cylinder does is improve airflow. The smooth radius taper attempts to create more laminar air flow reducing drag coefficient which increases air flow. Boring out the cylinder head does a similar thing. Both together ultimately gains a little more efficiency and therefore more velocity on the same setup(10-30fps in my experience depending on setup). So if you are already at your limit, this mod will not improve anything accuracy wise. If you do this mod, at 1J, I would expect the gains to be on the lower side do to the slower moving piston and lower air flow. Theoretically, It should still help some though and then you can cut the spring down a little to reduce bolt pull force and keep same power output. In my opinion not worth doing as the gains will not be marginal and probably not even noticeable.

Long Answer: Look up coefficient of fluid flow thru an orfice and laminar vs turbulent flow.

Why I like and do this mod: The reason I do this mod is trying to get the most velocity out of a stock VSR to make it the best it can be with no extra part cost. This is in the US where limit are higher and the gains from the mod is closer to the 30fps range. For instance, I had a friend on a tight budget who wanted to try sniping. So bought a mb03 on sale for $80 and it came shooting stock around 385fps (1.38J). After air seal mod.s and good cleaning it was around 400fps (1.5J). Boring and Radiusing/tapering the cylinder head it was sitting around 425fps (1.68J). Replacing the stock 300mm barrel with a longer stock barrel I had lying around (400-450mm maybe?) It was shooting right a round 440fps(1.8J) which is really close to our 450fps (1.88J) limit. So he had a fieldable gun that will last for a fairly long time (since it has a stock spring in it) that clocked in right around our limit for under $100.
 

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Discussion Starter · #3 ·
Short answer: No, not needed and will not offer any significant accuracy increase.

Longer answer: What tapering and boring out the head of your cylinder does is improve airflow. The smooth radius taper attempts to create more laminar air flow reducing drag coefficient which increases air flow. Boring out the cylinder head does a similar thing. Both together ultimately gains a little more efficiency and therefore more velocity on the same setup(10-30fps in my experience depending on setup). So if you are already at your limit, this mod will not improve anything accuracy wise. If you do this mod, at 1J, I would expect the gains to be on the lower side do to the slower moving piston and lower air flow. Theoretically, It should still help some though and then you can cut the spring down a little to reduce bolt pull force and keep same power output. In my opinion not worth doing as the gains will not be marginal and probably not even noticeable.

Long Answer: Look up coefficient of fluid flow thru an orfice and laminar vs turbulent flow.

Why I like and do this mod: The reason I do this mod is trying to get the most velocity out of a stock VSR to make it the best it can be with no extra part cost.

Thanks, I couldn't ask for a better answer. So what I need to do is a chrono test and see if it's exactly 0.99 / 1 joule. if not and I get weaker results (for example 0,8 / 0,9 joules), then I should do this mod. Exact?
 

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Yes, get a decent chrono. You will not regret it. If you are under your limit by 0.05J or more, I would try it. As 1Tonne recommends, if you are a little over your J limit, weight your piston a little with electrical tape and or solder wire and then you can remove the weight if spring relaxes over time.
 

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Discussion Starter · #5 ·
Yes, get a decent chrono. You will not regret it. If you are under your limit by 0.05J or more, I would try it. As 1Tonne recommends, if you are a little over your J limit, weight your piston a little with electrical tape and or solder wire and then you can remove the weight if spring relaxes over time.
Okay, thank you very much again.
 

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I used to cone the inside of the cylinder head but I never really found that it increased fps. I just done it as it is meant to make better air flow. But like I say, I saw no increase in fps. If there was, it would have been 1-2 fps.
I would keep the flat back end of the cylinder as you have an air brake. If you were to cone the cylinder, then your air brake would not be as efficient.
 

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Discussion Starter · #8 ·
I used to cone the inside of the cylinder head but I never really found that it increased fps. I just done it as it is meant to make better air flow. But like I say, I saw no increase in fps. If there was, it would have been 1-2 fps.
I would keep the flat back end of the cylinder as you have an air brake. If you were to cone the cylinder, then your air brake would not be as efficient.
Thank you!
You said I have an air brake, but I don't. I mean, the head of my piston is flat.
 

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If you have a 'coned' cylinder head, you will not be able to use a sorbo pad, so I wouldn't.
You can still use sorbo, just need to glue it to the piston head. Also what I have done that seems to be just as quiet as sorbo, lets you keep the sorbo off the piston (keeping weight down) and still gives the cone shape on the cylinder head is doing the "hammer" mod. I haven't compared any numerical results with it so purely theory/observation and may not be any better than a flat cylinder head with a sorbo pad.
I used to cone the inside of the cylinder head but I never really found that it increased fps. I just done it as it is meant to make better air flow. But like I say, I saw no increase in fps. If there was, it would have been 1-2 fps.
I too don't think you will see a lot of gain at 1J especially using heavier bbs (which you should). Come to think of it, my results were all measured with 0.20 at that time and not with the heavier rounds I actually used in game. I bet the gains would be less due the the slower bb/air velocity. I am really curious to redo this test and test actual Joule output with different weight bbs. I would still do it unless you really want to use sorbo on the cylinder head (rather than piston) as it can only help. Probably insignificantly but still.....we are snipers......got to squeeze everthing we can out of our rifles......even if it dosen't make sense. like polishing a already decent barrel, washing/sorting bbs, ect! lol.
 

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Get yourself one of these.

Better air flow and more quiet.

I run one of these in my VSR, it's great.

Just remember that cylinder head is mass produced as cheap as possible to cut costs, so it's a good upgrade for its to do with air delivery and that's pretty important.

I noticed a difference in all my upgrades, but do you really need it, not really but i would keep that cylinder standard and get the Laylax.

PS. I'm Italian also ciao. :)
 

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It's actually called a HAMMAR mod, and was invented by a member of this forum.
I have never used it myself, but I don't see why it wouldn't be good.
That is what I was talking about. Thanks for the correction. If you search "hammar mod" here, his thread will come up and I find it more useful than his video.
 

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The cylinder head does deliver air but from the experiments I have done, it did not really do anything. I used to cone out the cylinder head but now I do not bother.
The main difference in a more costly cylinder head is that they are steel and not brass. The brass ones tend to lose their thread after a lot of impacts. As they do this, they also slip past the thread on the cylinder, stripping the cylinder thread too. So both cylinder and cylinder head thread get damaged because of the weaker metal in the cylinder head. That is the main advantage of an after market cylinder head.
If you already have a steel cylinder head then don't get an after market one.
 

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While making your cylinder head look like a funnel isn't that great, drilling the hole to something like 5mm is a good idea as it gives better air flow and higher FPS, and sound is better too as you can use a weaker spring.

Only attempt this if you have a lathe, drill press, or are willing to buy another cylinder head.
That being said, ESC Works make a good cylinder head and piston, and Maple Leaf makes a good cylinder head, so I'd check them out if you want a better cylinder head.
 

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It's actually called a HAMMAR mod, and was invented by a member of this forum.
I have never used it myself, but I don't see why it wouldn't be good.
Ah. Thanks... I do recall reading about that a while ago in the Longrange AEG section... I think. Didn't know what it was called though.
 
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