Talon pcp Tank dump (edited)
Hi,
My Talon pcp can’t handle
samyang (eunjin) 16 and 19 grn.
Tank dump had occured at various fill pressures 3000, 2800, 2500, & 2200 psi .
What intrigue me is, it shoots smoothly for about 10 shots of samyang /eunjin 19grn after the dump. But with lesser impact at the target.
Power setting was at 10 and 11.
Seen the valve , no cracks or deformation.
Talon pcp
Calibre .177
Barrel 18 ”
Hammer + xtra wt
Almost new pcp shot about 70 pellets only.
Please suggest any remedy. Am new to AF.
What all will be required to convert it to .25 calib . besides the barrel.
Mk
All Replies
NO NO, I didn’t mean to tell you to brush your teeth 
http://www.brownells.com/search/index.h … &ksubmit=y
I think I’ll order some to have on hand ❗
Afterall, I’m only 70ish and plan to build a lot in the next 50 year’s.
Oops,
That is a condor valve stem.
Drain your tank and remove the valve. Check where the spring retainer nut it at and tighten all the way in.
Hi,
Here are the pics of the tophat (I stand corrected) pl see if it can be made out the types of valve by seeing this. As for me never seen a condor air rifle valve or tophat.
Pl bear-with the pic quality.
Regards,
Attachments:
Thru my building and testing, tank dump is a problem when the breech OD and the pellet/bullet size have a big difference and heavy slugs. Like .308″ breech and .177″ barrel. It acts like a step, the air expands and has to go out a smaller hole. This creates back pressure against the top hat and holds the valve open longer. Once it is held open to long it reaches a point where the pressure is higher on the barrel side and that is when tank dump happen.
I first ran into this problem when I was building my .308. Breech is .430″ and barrel is .308″. It took my a couple of weeks to figure out how to stop it.
There is 2 ways to stop it. You can stiffen the valve return spring or shrink the top hat gap or both. With the .308 I ended up running a 52 lb spring in my one valve that is 7/8″ thread on the bottle size and has a lot larger hole going to the seal. This valve runs a .100″ top hat and will shoot 171 gr slugs. The other thing is that the ports are 11/64″ and if I make them any bigger I get tank dump.
On my condor size valve I have a 49 lb return spring and it will shoot 171 gr slugs not problem. Ports are 11/64″ and then ported. This valve works with .085″ top hat. Any larger and it doesn’t work effiently.
The best setup is the .25 because the barrel is .308 and a .250″ hole. I have never had tank dump with .25. My .25 will shoot 89 gr slugs with .135″ tophat and a return spring that barely closes the valve when you push it with your thumb and let it go.
So first thing you can do is remove the valve and tighten the spring retainer nut all the way in. Then I know that .177 require a stiffer return spring then .22 and .25. Might want to get one for .177 just to make sure you have the right one. Wouldn’t be the first time AF screwed up when putting a gun together.
Hi,
Makes sense. This along with barrel polishing/ lapping will make my talon shoot like a whistle.
Please don’t take me wrong. but sometimes why does pcp airgun valve system sounds like rocket science to me 😳
How happy was I with firearms just a few 6 moons back then Talon
airgun happened. Now am back to kindergarten.
Regards,
mk
Sorry for the slow reply but being an avid DIY nut, I pulled my own tooth last evening. Actually, it was amazingly painless but the cheap rum I used for anesthetic and courage, led me to the throne room to kneel and upchuck several times. Damn cheap Wal-Mart rum 👿
I use the paste although you will find it a thin paste.
It does a good job on my already lapped barrel but is non abrasive and probably won’t remove the machining marks that the fire lapping will.
Besides the Wheeler Engineering bore lapping kit, MidwayUSA.com has JB Paste that is reported to do an excellent job and is non embedding and they say it breaks down in use to easily be cleaned out.
hi,
Lol….. 2 things
1. I hope you were not you alone during that self dental surgery.
Its ok pulling out ones own tooth when its already loosen.
But its well known in medical history that it may lead to medical emergency
if vaso-vagal attack happens. again vaso vagal attack during tooth extraction is very
uncommon. Yet, to be on safer side do it in presence of someone nearby 😉
After the extraction enjoy some icecream which will reduce any bleeding if present
also slow down inflammation.
2. toothpaste for barrel polishing. I know you are pulling my leg.
what about BRASSO liq. which are normally used to polish brass. These are easily available
as they comes under household items.
regards,
mk
mkfs,
Sorry for the slow reply but being an avid DIY nut, I pulled my own tooth last evening. Actually, it was amazingly painless but the cheap rum I used for anesthetic and courage, led me to the throne room to kneel and upchuck several times. Damn cheap Wal-Mart rum 👿
I use the paste although you will find it a thin paste.
It does a good job on my already lapped barrel but is non abrasive and probably won’t remove the machining marks that the fire lapping will.
Besides the Wheeler Engineering bore lapping kit, MidwayUSA.com has JB Paste that is reported to do an excellent job and is non embedding and they say it breaks down in use to easily be cleaned out.
Ok here is my take and some info on tank dump.
Thru my building and testing, tank dump is a problem when the breech OD and the pellet/bullet size have a big difference and heavy slugs. Like .308″ breech and .177″ barrel. It acts like a step, the air expands and has to go out a smaller hole. This creates back pressure against the top hat and holds the valve open longer. Once it is held open to long it reaches a point where the pressure is higher on the barrel side and that is when tank dump happen.
I first ran into this problem when I was building my .308. Breech is .430″ and barrel is .308″. It took my a couple of weeks to figure out how to stop it.
There is 2 ways to stop it. You can stiffen the valve return spring or shrink the top hat gap or both. With the .308 I ended up running a 52 lb spring in my one valve that is 7/8″ thread on the bottle size and has a lot larger hole going to the seal. This valve runs a .100″ top hat and will shoot 171 gr slugs. The other thing is that the ports are 11/64″ and if I make them any bigger I get tank dump.
On my condor size valve I have a 49 lb return spring and it will shoot 171 gr slugs not problem. Ports are 11/64″ and then ported. This valve works with .085″ top hat. Any larger and it doesn’t work effiently.
The best setup is the .25 because the barrel is .308 and a .250″ hole. I have never had tank dump with .25. My .25 will shoot 89 gr slugs with .135″ tophat and a return spring that barely closes the valve when you push it with your thumb and let it go.
So first thing you can do is remove the valve and tighten the spring retainer nut all the way in. Then I know that .177 require a stiffer return spring then .22 and .25. Might want to get one for .177 just to make sure you have the right one. Wouldn’t be the first time AF screwed up when putting a gun together.
Polishing the bore is just one of the mods that can improve velocity and consistency.
ROACHCREEK has written a bit about using the Wheeler Engineering Bore Lapping Kit for fire lapping.
Knifemaker has a secret process that I’m sure he would share with us here 😉
Here is a picture from the Wheeler manual.
For the .25/.257 bore RC advised a modified method of using the Wheeler kit.
I really don’t know if this form of fire lapping would be advised for the .177.
I bought a TalonTunes custom 12″ .177 barrel and won’t remove it from my Condor that was a hi flow 24″ .22. I modded the arrangement of the extra hammer weight and got it working great when many said it couldn’t be done 😆
Now, there are other ways to lap/polish the bore. I had used PEEK multi purpose polish and FLITZ while others report good results using ?MAAS. It is best to work from the breech so as to avoid damaging the crown. Talon Tunes produces a beautifully modded polished barrel with a highly polished breech slide area and a custom re-crown.
In theory, the machining marks between the lands are the culprit that cause unwanted friction and rapid leading.
Then too we are cautioned to NOT OVERDUE THE PROCESS.
More info about fire lapping is available from http://www.wheelerengineering.com
😎
Hi,
Thanks for the welcome , even more for the valuable advices.
I would like to know which form of ‘PEEK’ multip polish you used for lapping.
Googled the ‘peek’ found liquid, paste and foam etc. Am quite at sea which one to buy.
Regards,
BTW :tag: mkfs,
Polishing the bore is just one of the mods that can improve velocity and consistency.
ROACHCREEK has written a bit about using the Wheeler Engineering Bore Lapping Kit for fire lapping.
Knifemaker has a secret process that I’m sure he would share with us here 😉
Here is a picture from the Wheeler manual.
For the .25/.257 bore RC advised a modified method of using the Wheeler kit.
I really don’t know if this form of fire lapping would be advised for the .177.
I bought a TalonTunes custom 12″ .177 barrel and won’t remove it from my Condor that was a hi flow 24″ .22. I modded the arrangement of the extra hammer weight and got it working great when many said it couldn’t be done 😆
Now, there are other ways to lap/polish the bore. I had used PEEK multi purpose polish and FLITZ while others report good results using ?MAAS. It is best to work from the breech so as to avoid damaging the crown. Talon Tunes produces a beautifully modded polished barrel with a highly polished breech slide area and a custom re-crown.
In theory, the machining marks between the lands are the culprit that cause unwanted friction and rapid leading.
Then too we are cautioned to NOT OVERDUE THE PROCESS.
More info about fire lapping is available from http://www.wheelerengineering.com
😎
You don’t lap it that far. 😆 Think gently polish. Waiting for a pic of the top “HAT”.
You’ll just have to buy an additional AF rifle in .25 to experience the best of both worlds,
like I did ❗
Sir, I will be mighty thankful if you throw some light on lapping the barrel. How to. Will it not erode the lands and leveled with the grooves 🙄
Told you am new to Airforce airgun.
mk
KnifeMaker
It should not have the xtra weight hit me. I think I got a refurb Talon.
Thanks, things are more clearer after joining this forum.
Will try to post the picture of the tophead and I hope seniors will be able to make out if my Talon has the Talon or Condor valve by looking at the tophead.
mk
If you polish or lap that .177 bore you probably won’t want to change out the barrel.
You’ll just have to buy an additional AF rifle in .25 to experience the best of both worlds,
like I did ❗
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Drain your tank and remove the valve. Check where the spring retainer nut it at and tighten all the way in.
😈 😯
Don’t know whether to sulk or smile 😐
Condor valve mysteriously found in Talon PCP yet the return spring seems to be very stout. Can’t press with thump when the tank is emptied. Sorely designed/destined for .177 to dump with heavy pellets 😆
Will wait to recover from the shock 😮 Then look around for the right tool.
Looking up your old threads in machin n tools it appears one need to open the brass and not the one threaded to the bottle. Would have opened this part with ease but to open the brass thing within it will require some special bizarre tool with same principle of a pointed tongs or forceps. For this I will have to hunt.
Thanks, in one glance you told me its condor valve.
BTW what Talon valves looks like.
Is it one of the two tophats shown in amazon.com by cyprus. One of them is same as the one found in my Talon and the other straight stem. If so then 😳 coz I took the pain of clicking fotos with pellets for size comparison of the tophat. lol
reagards,
mk