Low power "duds" shots
I have a TalonSS and when I shoot a 40-50 shot string I’ll have 5-6 that are at like half power…you can hear it and feel it….I tore down the top end today and cleaned everything (it really didn’t need it) but that did nothing to resolve the low power shots..Anyone with ideas/suggestions, please advise..TIA
I’m thinking problem with valve, but have NO IDEA of what to do or how to do it
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Congrats!!!!
Did you remove the valve stem or just clean it “in place” using the method above… I’ll be sure to use the same method when mine goes down the tubes.
wellI have a chrony, but don’t need it to tell when shot is a dud..the ones that I can actually watch go down to the target and hit 6 inches lower than all the others is a dud…nothing to measure 😆 😆
Dumped air..wiped down the stem, blew off with 120psi air, pushed it in a few times, used a toothpick to put a small amount of diver’s silicone around the stem….Ran 300 pellets through it yesterday morning..checking fps/shot counts at different PW settings….didn’t have one single “dud’, so guess that fixed it…COOL BEANS 😀 😀
You need a chrony to test valve lock accurately ~or~ experiment with 2400psi 2600psi 2800psi and 3000psi. See where your POI is with a three shot group.
Yes, I always pull bolt back and rotate to the left, since I reload exclusively with my left hand……I didn’t think I’d be getting valve lock @ 2800psi…matter of fact I wouldn’t think it would occur at any range up to the max fill of 3K psi.
Packrat & Synopsys,
I had the same trouble, I had to ensure that the breech was pulled back against the top hat.
I had lost my little washers that go onto the breech knob early on in the ownership of the rifle. I made some out of nylon washers and set the top hat a little further out.
This condition caused some peening that was slowing the breech down. I had to relieve the bur on the frames cocking notch.
Any idea on how much play should be present between the top hat and breech when the breech is pushed to its forward limit?
Roachcreek
Roachcreek
Pack,
When you empty your tank, push on the tophat to see if it’s sliding well… This will give you an indication of it’s ability without taking the stem out…
You shouldn’t be getting valve lock at 2800…
Do you pull the breech back and put the cocking know to the same place every time?
DING1 DING! DING! Maw–as I was reading your post, it’s like a light went off in my burned-out brain….and here’s why-I live in south Georgia…GAZILLIONS of pine trees, PLUS I live out in the country..Every year at a certain time all the pines trees produce these little “pod-like” things that are nothing but a ball of YELLOW POLLEN. This pollen is SO BAD that when it rains, the water running down the sides of the roads is YELLOW (no exaggeration here, it really is that bad!!) SO, if I’m outside target shooting or in the woods looking for tree-rats, that pollen is gettin’ on everything, including TH and the 0.070″ of exposed valve stem…some of it just has to be finding it’s way down inside!!! Got to be it 😀 😀 😀 I shall take care of that little project first thing this morning..THANKS for your post- I bet cleaning that will solve my problem…EXCELLENT !!!
I’ve had that problem before and I would just pull the tophat and stem out of the tank and clean it and run a q-tip down inside the bottle, then ever so sparingly put some silicone on the stem and smack it back in the bottle.
Thanks for quick reply..I mentioned fill pressure to let you know that I’m NOt one of those that fills to 3,200psi..I can see where that might “lock”the valve.. Perhaps opening up TH gap a little more would help..Also, if the hammer spring was stiffer and/or had a heavier hammer would also help with the low power shots..But what makes all that seem not viable is the fact that the gun just started doing this all of a sudden, that is I have done nothing to it, no adjustments or changes of any sort…maybe I should try setting PW up a little..I normally have it set at 4.8…Anyway, certainly lots of things to consider…gonna crank up PW and see what happens! Thanks agsin for quick reply 😀
My top hat is somewhere around 0.086… It doesn’t take much… if the hammer slaps into the breech and the breech isn’t resting on the top hat then you will get a dud.
Now… for valve lock.. The pressure in the tank keeps the valve SHUT… If the pressure is too high then the hammer is unable to open the valve for long enough to get a powerful shot… This means the valve is not just SHUT it is LOCKED. The solution to valve lock is to bleed the tank until the PSI drops to the point where the hammer is able to over come the pressure repeatably and reliably for you to shoot accurately. Also referred to as the power-curve.
I fill my hunting bottle to 2500psi and get 40 powerful (50 yard) shots in TSS 177 with Kodiaks 10.6gn.
I have a second bottle filled to 1500psi that I use for birds and plinking. This extends the usefulness of my SCUBA tank and reduces my gun’s report (happy neighbors).
Remember its not about PSI its about accuracy. The gun is designed to have a long shot string over a variety of pressures. Don’t get hung up on what your starting pressure is 🙂
dmeader..I don’t THINK it’s bad, I know it is 😀 I ‘m guessing the 8fps to 22fps figures you stated were actually 8fpe to 22fpe 😆 😆 😆 Cause if your gun is only getting 22 fps YOU have got a serious problem!!!
It’s been over a month since I lowered the TH down to 0.080 “, so I don’t think that’s the problem, but don’t know for sure..it just started doing this on about the last 3-4 refills..I normally fill to 2800.. Can someone explain to me exactly what VALVE LOCK is ??? I’ve seen it mentioned occasionally, but never explained… and BTW, I have totally emptied the tank and re-filled..but it still gets the “duds”…so that didn’t help either 😥 😥 😥
I had the same problem with my TSS 177 when I bought a second bottle. The new bottle had slack between the top hat and the breech. If I failed to pull the breech onto the top hat the remaining gap would cause a low power shot. You can adjust the top hat to remove the slack, be sure not to over tighten and use loctite to prevent the grub screws from unwinding.
It sounds like you don’t have valve lock since you’re referring to a 50 shot string and most likely know your power curve.
You think thats bad. Just rebuilt my one. Had the o ring mod done reground the valve and cleaned the barrel. Went out to set it up today cant set the power. Varies from 8fps up to 22fps(UK limit 12 I aiming for)
Funny thing though it shoots much better at 22.
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I too have had some duds
its all about the breech being all the way back on the TH
I have a custom knob and have like a gap of
3/32″ between the knob and frame
yes a nylon washer would be key
After reading this post, I just put 2 lubed o-rings on the knob
nice and snug, temp fix
think I need a new knob made with a fatter contact area
SAW