.257 condor barrel velocity w 88gr Spitzer
Im currently using the .257 caliber 700mm barrel and 100 gram hammer from rl airgun supply. My top hat is unscrewed 2 full turns open to increase valve output, and im getting about 600 fps at the start of a 2500 psi fill at a power setting of 12. I figure thats about 60 fpe. I get a 900/875 fps respectfully from big boys (40gr) equaling the same 60 fpe. So, my question is does any one else run this configuration, and if so can anyone suggest any thing that will help get th 88 gr slugs up to the 900 fps range? Has any one installed the extreme valve from rl yet. Im looking to get up to 100 fpe from this gun. Any advice would be greatly appreciated. Thanks Robert
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Hey Rick, welcome aboard! Thanks for checkin in,,,,, it’s not my orig. post but I find your input relevent and am interested in what others are doing and what works and doesnt work. I think thats the beauty of these forums. Nothing too formal and everyone pretty cool and laid back. Nothing too uptight, and everyone is pretty patient. I also havent been online as much as I used to, or as much as would like . I’m glad to hear that the RL Extreme Valve is actually a worthwhile work in progress and not just a hyped up hop up . I am also glad that i kept an open mind to it and getting the word on it from others. It seems as if it isnt such a bad deal and is quite usable. Hopefully knifemaker wont leave us hangin in suspense for too long, as I am very curious as to hearing a bit more about these valves. Especially if there is no more Dyotat valves available? So, whats the 411 on these new valves knife?
I remember first seeing the RL stuff advertised but the Extreme valve was always coming soon or not in stock. He is now stocking the Extreme Valve? Is the currently shipping product same as what ya got knife ❓
I only check in every once in a while these days and maybe this doesn’t apply here, sorry if it’s out of place.
I have the .25 cal with Randy’s extreme valve and I’m getting 115 fpe with Jerry’s 66 gr slugs at 2900# with the pw at 4.
Still love the gun, the slugs are nicely accurate at 60 yds.
Knife,
I picked up Randy’s Condor this past February with 700 mm barrel and extreme valve. What is different about this valve from mine as I cannot get close to that performance from my set up.
I am currently doing a full test on some R&L Prototype valves. So far, Impressive!
While not full out power, such as found in a Dyotat valve, which at the moment, is unobtanium, the R&L is a very well machined item.
I tested both the R&L valve stem only, in an AF Valve body, and the R&L VS in an R&L Valve body.
I will be posting a full accounting of the test in a few days, but so far, The R&L unit has given me a full 185 fps increase with my chosen NOE bullets, over a ported AF valve and valve body.
This is roughly 60 fps less than the Dyotat valve could give me. My Dyotat valve is Doug’s .25 valve, not his full on .257 valve, as my breach had already been turned down to factory .25 specs.
More to come!
Knife
Ok just for shits and grins i took a few chrony shots. My 30″barreled dyotat .257 with approx 2800 in the stock tank/dyotat valved untethered* with a 88gr RJ Accurate BigBore Ammo Spitzer measured 1004.fps , 997, 1003 and 999 with just under approx 2400 according to the stock and questionable air gauge. My altitude approx. 890 ft above mean sea level.
* Note that I usually do all of my shooting off the bench and tethered to a 88cu ft 3500psi scuba tank and will cascade it to another tank when it reaches 3000 after about 100 or so shots. With this setup the last time i checked i was getting around 1050 with the 88gr spitzers.
I still like those RJ 88grainers however there is a considerable flatter trajectory with the 74gr Lymann at 100yrd distances that I am able to shoot at. I am not sure what velocity i am getting with the 74gr . I will need to run them over the chrony next time i go to the range. The 74gr work out to be pretty close to just a “smidge” under one mil dot at 100 with the 88gr sighted in center at 100 if i recall correctly… Your milage may vary and my results are vaque, unscientific and lack any standard control.
Hi Robert,
Yeah, you are definately underpowered in my limited opinion. I am not sure how much you can expect from only a 2500 psi fill. I know that there are many others more saavy with performance tuning and working the numbers that can better forecast what is achievable with 2500 psi. It very well might be capable but its going to take a larger volume of air to get things going faster. Also I would suspect that you really arent going to acheive much by preloading your hammer spring with such a high power wheel setting. At only 2500psi your 95g hammer doesnt have alot of force to overcome opening that valve. You likely are hitting the valve so hard that it fully opens the valve its full limit and then some. Not only does this induce additional stress to your gun but likely the additional energy of the valve fully slamming the end of its limits probably is robbing power by reducing the dwell as it rebounds or bounces back and closing sooner. That energy dissapates somewhere if it isnt overcoming the force of the air pressure. I am going to guess that 2 or 3 is going to be the maximum effective setting the powerwheel will have at that pressure.
As for the Tophat….. Well I am very unclear of where you should be. Almost everyone uses a onepiece tophhat in their guns. The Talon Tunes one with threaded restrictors are used in many performance tunes. For custom big bore guns a custom built onepiece tophat with a diameter matched to the bore of the barrel and a matching breech with the proper diameter bore is the required fare. With these applications its really all about the Custom fit hand tuned one off type of thing. The Tophat is custom made intregral to the valve body and specs matched closely to the required parameters of your particular build and use. To fine tune a valve such as the Dyotat, the builder uses hard rubber spacers or shims similiarly to the way users have found usefuleness with O-rings behind the Tophat to limit travel and cushion bounce.
As for the RL Extreme Valve I can not offer any insight or opinion. I have only heard comment or rebuttal that it may still be a bit lacking in what it can do in our .257 applications. Without personally observing or experiencing I will reserve judgement, as many times there may be more than one way to skin a cat or get to where ya want to go. My experience is limited with going from zero to 100 and little experience inbetween. I started with a bone stock .177 on CO2 , upgraded to a std HPA valved tank the following week and then jumped into a Custom 257 build within only a few short months later. Fortunately I was able to quickly assimilate and have gained much through the experiences of many knowledgeable and kind others. As you may realize there are many different paths and options to choose.
Sounds like you are getting pretty close, roll up those sleeves and dive on in…… the water is warm.
I would find the biggest bored out and ported valve body you can get your hands on and match it with the proper breech and increase your pressure to 3000-3500 psi and try a bit lighter cast bullet properly sized at no greater than +.005, of your slugged barrel diameter measurement, also use 100% lead for your castings. Using harder alloy creates more friction however the 100% lead does foul the barrel faster requiring frequent swabbing to reduce the lead fouling which also creates drag…. Many guys extoll the virtue of lapping and polishing the barrel. I simply polished with flitz after a good solid break- in of a few thousand rounds. The barrrel is just coming into its own.
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My valve is still available. I’m just at the mercy of the machine shop. They are making stems for .25 right now or should I say when they get around to it. I changed the stem shape and material it’s made out of. Probably next month before I get them.