.25 cal Blod valve strings
I’m using a Talon with a 21″ .25 cal barrel, Blod valve, included heavy spring installed with powerwheel set to 00, stock Talon hammer. Top hat set at .258. Prochrony chronograph. Shooting Kodiaks.
2600 PSI fill
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25 good shots
2800 PSI fill
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45 shots!!!! Wow. 😯
Going to try a 75 gram hammer when it gets here, but i’m closing in on the bell curve. 😀 Too windy to shoot for groups, but i was hitting my 3″ target at 85 yards with regularity, though i was not really taking my time, and shooting off a bipod, no rear bag. What do you guys think?
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The threads could have been as Pabs suggested less deep
also no need to stop them abruptly, instead withdraw tool gradual to reduce/illiminate the stress riser.
but then again Blodnob already knows that.
Walter….
programming a tool path loses out to real understanding every time!!
And that 90* shoulder is a stress riser waiting to fail.
Neither one kept me waiting very long. 😡
I’m te thinking Brad has cut the thread deeper than the original. Very shallow threads on mine compared to those pics……
programming a tool path loses out to real understanding every time!!
And that 90* shoulder is a stress riser waiting to fail.
I’m te thinking Brad has cut the thread deeper than the original. Very shallow threads on mine compared to those pics……
programming a tool path loses out to real understanding every time!!
I’m te thinking Brad has cut the thread deeper than the original. Very shallow threads on mine compared to those pics……
too weak for the job
Yes, That must be the case. I have filled in the well with a delrin insert to make the breech flat faced. Then you can reduce the tp setting to what Blodnob intended it to be (about 2-3mm) Maybe with the tp so far out using a breech with a well it is causing lateral forces on the stem which is snapping it??
Stow, Try to make your breech flat faced, then you can reduce that outrageous tp setting…
I wonder if a lighter spring behind the tophat would increase the life of the stem but still seat the delrin cylinder enough to fill the tank…
I removed the valve from my tank. It was scary and loud.
I tried the angling idea and unless the o-rings are worn it will not twist… 😕
I had approx. 60 shots through the first one, almost four hundred through this one. All new o rings, no air leakage. What a bummer. 🙁
Here is mine…
Looks like the shaft 😀 may be a little thin where the threads end and the force of the spring during the firing cycle causes the wall to fail eventually…
How many shots do you think you had into each valve and I wonder why it isn’t happening elsewhere…
Possibilities could be misalignment of bolt with respect to the tophat. Worn o-ring could create that misalignment. You confirmed that the breach was tight against the tophat when pulled back… Do you have a hammer slap mod?
If your running the tophat like the photos above the bolt is probably angling a bit when struck. I know with my tophat gap at 0.04″ or less (on the af valve) my breach wants angle since it is no longer really riding in the frame or on the back o-ring that rides around the barrel…
Someone needs to make a longer bolt with two o-rings that ride on the barrel. 😯 Would probably help create more force transfer from the hammer to the tophat as well… (I get half :wink:)
bolt=breach, the thingy that has the KNOB!
Yes they both broke exactly at the ends of the threads. I suspected the same thing about a stress riser because it happened where it did both times. After it happening twice, and not hearing about anyone else having this problem, it made me worry i’m doing something very wrong for them to both fail so quickly.
Last time i used the bleed hole, it was scary, and loud, but it worked as it should. If brad had not designed that in, i don’t know how you would get the air out without just cracking it a bit and hoping it would leak down slowly.
Pure curiosity here. No witch hunt intended… Brad provided me with some of the best service I have seen this year.
I will take some shots of my stem for comparison. Did it break at the end of the threads or in the middle of the tube? I wonder if it’s possible to avoid this somehow with settings or if it’s a machined mark creating a stress riser.
How do you get the air out now? With the bleed hole?
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also no need to stop them abruptly, instead withdraw tool gradual to reduce/illiminate the stress riser.
but then again Blodnob already knows that.
Walter….
Indeed. My valve has been going strong for over a year now. My rifle is used in the field, clearing areas of rabbits for farmers and the like, so its not exactly mollycoddled…(as you can see by the rust… 😳 ) 1000’s of pellets have been sent downrange by it.