Blodnob Valve, 100g hammer, 25lb spring, hhhmmmm

All right i tried it and wasn’t impressed at all, dam that 12″ barrel. More power, yes. But,my consistency went to hell and my shot velocity was less in FPEs on shot (last one ) 14 as it was on shot 20 with the factory spring and my 75g hammer. Could be that i’m just not using the valves full potential with the 12″ barrel. I really believe this to be the case. We’ll soon see in the future. Will drop in the 18″ one of these days and do a string or two. I did have the 18″ in last year and got over 1000fps, but it wasn’t neighbor friendly, so i need to get my shroud on as well. For now here is the string i shot.
100g hammer, 25lb spring, 21g Kodiaks, tophat set at 2.5mm which yields good consistency with my other setup mentioned, PW set at 6. 2.4mm yields a bit higher power and i will do a string at that setting as well with the heavier configuration. I just don’t like all that extra force going on in the inside of my rig, Sean can build any replacement part he needs, i can’t, most the pity. I can assure you the force of a 100gram hammer being pushed by a 25lb compressed spring is plenty powerful.

01. 903.8
02. 899.3
03. 901.4
04. 894.1
05. 896.2
06. 885.8
07. 881
08. 874.7
09. 867.3
10. 866.4 (10shot string) 887avg fps, 36.8fpe, 37.4fps extreme spread
11. 861.6
12. 854.3
13. 852.8
14. 842.3 61.5 extreme spread.
Done, saw all i needed to, made an avg. of 30fps more in power, which is dam good. But doubled my shot spread, not good for me. with the same tophat setting and the above mentioned factory spring w/ 75g hammer, i had a 10shot avg of 853fps which did jump around a bit shot to shot for the first 10 shots and settled down to a extreme spread of 37.5fps after 20 shots with a avg. velocity of 850.9fps for 33.9fpe. That is still a near 3fpe increase over what was previously posted, but that thread went to the dogs 😆 So i’ll continue here.. My goal is to get as much power while maintaining a reasonable shot to shot spread. I’ll turn down the tophat to 2.4mm and see if i can get a tighter shot spread. I tried 2.3 and got some tighter #’s but with a much lower velocity. Aaahhh the fun is in all the fine tuneing, without it this would be just another gun to collect dust. This platform is just full of fun. So many different configurations and possibilities, the challenges are endless.

Where is everyone elses info??

Now, Sean knows his valve and it does have a huge orafice, i was very surprised to find such a tight spread considering the tophats opening. Using just the 12″ barrel i believe alot of air is being wasted using a heavy hammer/spring combination. I’ll know as soon as i drop in the 18″, just need to find the time to get the delrin bushings drilled out and tapped or make a pair of new ones, out of a pair of 1″Dx 9/16″ opening shaft collars. Just need to open up the diameter to 16mm another 1/16 or so. I’ll post a how to when i get around to the project. They are available at the hardware store. 1 set screw to secure it to the barrel. Pretty much exactly what is currently being used on the barrels as bushing now. I can see no difference.


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I don’t know about you mike but my shroud shrinks a bit when its gets that cold out 😛

Ha, had nearly -50 wind chill. Not bad, nearly balmy. haha Want to see triple digit, that’ll get your attention.

For me the 24 with shroud is more than I usually need and a bit to heavy for my preferences. If I really need to blast will grab a powder burner..

WoW! Your going t freeze your shroud off!

Shit we just had those winds BUT, with a temp of -6 degrees.

I’am working on my shroud now, the PVC one. Ran into a problem and had to revamp it. Have some 1″od ali tubing if all else fails. 😆

I know what you mean. A shrouded Condor kinda reminds me of a Kentucky Long Rifle. I do enjoy the short carbine. I have a 7.5 shroud on the SS right now. But I just made a 5.5 for it. Will be testing as soon as these 45-55mph winds leave central Texas. Man, I need to gain some weight. At 225, I’m about to get blown away!! Lol!!!


Thanks Mike. That was my thought as well on the barrel. Just have the 18″ cut down. In your case the same have a current barrel sent out to be spun down to the 12mm.

Adam, comes up with some pretty dam good ideas. Taking 2″ of the end of a 18″ so it fots nicely in the TSS frame is a good idea with minimal velocity loss. I put my 6″ shroud on and it makes the gun pretty dam long. Don’t know how these guys do it with the shrouded 24″ condors. I quess i just like the look of a carbine.

Love that idea of just a bit longer barrel. I asked LW for one with the 12 mm dia. but they wanted an arm and a leg for one. Probably easier to have a longer barrel cut down given one can access a lathe or someone who will do it.

Good luck Clint. Have fun messing around.

Looking forward to your results! Mike

I like the 16″ barrel because I can get my end cap back on and it will look like the SS but it is not quite. Of course with the shroud on it is very quiet. So I do not know when I will use it with the end cap…lol. But if I want a short gun then I have that option.

With the modded valve I get 855fps with Kodiak and 955fps with CP’s

Thats the fun of it all Mike, especially when temps have been the way they’ve been single digits a warm(20’s-30’s) 🙂 and single digits again.

I’ve gotten the Blodnob valve up to the mid to upper 40fpes but with a large shot spread. I’m after a shorter rig, 45-50fpe and a good shot count. I can get that with the 18″ barrel, i know it. I was seeing how far i could push the 12″ with Sean’s valve for myself and any others who have the valve and lack the time to experiment with it. I’ve layed out tophat settings, spring weights, hammer weights and alot of shots over the chrony. To me it breaks up the stock/grip making and i enjoy exploring the possiblities of my TSS with this valve. Just wanted to inform that one is limited with a 12″ barrel

Now when i take into account i only have a 3000psi tank and a 1.5hr round trip to get it filled. I want as consistent valve, which i got as well, but with th 12″ barrel i’m not going to get both the power and consistency i’m after. Which was the point of my experimenting. I will drop in the 18″ and put my shroud on and i know i’ll be shooting kodiaks at their velocity limit and have a good consistent string. With all the experimenting with the 12″ i know what to look for now and what kind of shot spread i should see. I’ve become very familiar with the valve, which one has to in order to get the most from it. Just thought Walter was putting words in my mouth which i didn’t speak. Sean gave me the valve and i’m very gracious for it. The last thing i’d do is put his work/design down. Its just apparent the valve isn’t going to perform the same with a 12″ barrel as it would a 18″, much less as it would a .25 in 24″ configuration. Its is a valve which excedes all 3 of AF valves and then some, as i could shoot low power .177 or high power .177 with a restrictor installed and the tophat adjusted. And the same for all other caliburs in all barrel sizes. Seeings that i wanted to stick with the 12″ because i like the compactness of it, its what i wanted to test with and see how far i could push the valve. I got close to what i wanted in velocity but not quite the consistency i need as well. So i’ll move on to the 18″. Never meant to insinuate Sean’s work was anything less then topnotch. If anyone else has done more experimenting then i with his valve, step up and tell me what i’m doing wrong. The answer is nothing, the numbers/consistency i’m after isn’t possible with the 12″ barrel, IMHO. I’m after a less then 2fps drop in velocity from a 20-30 shot spread. The valves largest restrictor is 4mm a bit larger then 5/32″ drill bit. Thats just to big of a port for a 12″ barrel to take advantage of with any kind of consistency. I’ll try one more string with no valve spring in and see if any improvement is noted??

Hey, maybe its just me and i don’t know how to work with the valve, even though i’ve tried different valve springs, hammer springs, hammers and every tophat setting from 3mm on down to 2.3mm. Have had a high of 46fpe with a avg. of 44fpe and a spread of 76fps with Eun Jins. Seen spikes higer but with the tophat set out to far to maintain any kind of consistency , like 902fps with EunJins thats 50.5fpe.

I really wanted to stick with my 12″ and shoot consistently at around 950fps w/Kodiaks. that is what i’ve been after. I just really don’t think its possible. The 18″ will yield a solid 20-30 shot string at the fps mentioned above, i know it. Maybe a 16″ barrel like WOK would be the ticket, we’ll see what the chrony says with the 18″ in. 😉

Dono, doesn’t seem anything wrong with fooling around with a rig experimenting with different set ups.
Granted longer barrels in AF pcp is gonna give one greater efficiency and there are a number of valves to work with from AF that pretty much cover a good range. AF rig offers quite the combinations to mess with. If ya add all the mods and parts calibers etc. to the mix it’s an impressive array of possibilities!!
Blodnob/Sean valve is really pretty and nice work, something more to add to the mix and to explore. Of course then you have folks like Walter and Cygnus among others that have gone way beyond the norm with incredible power levels. To get way up there one does need the barrel length.

That said I’ve enjoyed messing with the 12â€

Voltar, i was refering to the spring and 100g hammer and this all stems from a previous thread as well. But here we go. Quote: “Dam that 12″ barrel”
“Using the 12″ barrel i believe alot of air is being wasted with the heavy hamer spring combination”,
“could be i’m not using the valves full potential with the 12″ barrel”
end quotes.

Thats 3 times i mentioned the 12″ barrel and its affects. Not to mention the times i spoke about in in the other thread. I know what its capable of. I think your reading way more into this then you should be. Just posting the facts as the chrony reads them. I’m looking for consistency in the valve as well as power i found it with the stock hammer spring and 75g hammer. I’ll drop in the 18″ barrel and be right where i want to be. My Thread title reads completely different then what you have quoted, if you have followed the other thread then you should understand what i’m trying to do. Don’t put words in my threads that aren’t there. The Valve is awesome as i stated many times. But with a heavy hammer and hammer spring it is not going to perform as well as a lighter configuration with a 12″ barrel, thats all.

Loftus you should see my other thread on the topic, 2.5mm tophat and a spread of 37.5 fps over 20 shots 2.4mm gave me a bettr velocity and a couple fps more on the shot spread. You should be getting more shots. I tried the 2.9, 3mm tophat settings and ended up wih some big shot spreads. When i backed the tophat down things tightened up quite a bit. I still get 1000+fps with the 18″ and kodiaks i’ll post a full string in the near future.

You guys seriously need to lighten your hammer. 100 grams is for 150+ rifles.

Mine did 35 ft.lbs with a 10% stiffer spring and a 25 gram delrin hammer.

Valve stroke needn’t be more than 2 to 2,5mm.

Just my 0,02



i get 1080fps with a .25 24″ barrel,and one of seans valves,using 30g kodiaks,and get around 12 quality shots at that sort of velocity before my bottle needs a top up,oh its a real thumper,tophat turned out no more than 3mm,

your thread title reads ‘Blodnob bits hmmmmmmm’

wher you say you mean ‘ 12″ barrel sucks’

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