GTA
General Discussion To Gateway To Airguns => The Shop => : tjk August 30, 2009, 11:50:13 PM
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on getting the most accurate readings on a F1 chroney. Height, distance, etc. tjk
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Don't know about accuracy, Thomas, but I get nice consistent readings from my Beta by ALWAYS using the same light source, even when using it outdoors. I took a large piece of cardboard and cut two slots for the diffuser screens, same width but slightly shorter so it sits on the diffusers. I then place a halogen work light next to it, shining down on the diffusers. I only use one head, and aim it between the diffusers and about 12-18" above them. I then set the first sensor about 1-2' from the rifle muzzle. Try to shoot about 6" above the sensors, and shoot straight across the sensors, both vertically and horizontally. And watch out for fluorescent lights anywhere in the "view" of the sensors, that will mess up your readings every time. Hope that helps!
Dave
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Thomas:
Ditto on the cardboard. You want the space between the two diffusers shaded so there is no "cross talk" from the light. I use mine mostly indoors and have the F1 Chrony at bookshelf height, about 3 ft from the ceiling. I use a halogen desk lamp and instead of aiming it toward the diffusers, I shine it on the white ceiling above the diffusers and turn out any other overhead lights in the room. I take a 3-ft section of 1x6 board and set one of Timmy's large pellet traps on the end of the board on the bookshelf, and then I clamp my Chrony on the board about 2 ft in front of the pellet trap. I put a target on the trap centered about 6 inches above the sensors. When I shoot, I stand back about 5 ft from the Chrony, set the AO on the scope to the shortest distance, put the cross-hairs on the bull, and take care to make sure that the vertical reticle lines up with the sensors on the Chrony and that the "V's" made by the small rods holding the diffusers are aligned symmetrically front and back, in the scope's sight picture. At that range, the POI is lower than the POA and the pellet passes about 4-5 inches above the sensors. That way, it doesn't shoot up the bull on the target and I have a consistent POA to shoot at, standing. Seems to be pretty consistent. I occasionally check the set up with my SPP Beeman P3. It is a consistent 410 FPS with RWS Hobby, and I can check the Chrony's readings for accuracy with it.
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Thanks for the tips guys. I've seen and have used Bob's set up stand for his chroney,...but it's been a while since I've ventured over there,...and I couldn't remember the hieght and distance for a consistant testing. I'll try to card board trick tonight!!!!! Thanks again, Thomas
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Oh, I forgot to ask something else about the diffussures,...will taping them with clean packaging tape hurt the defussures performance? Sometimes when I move/ remove them ( like outside on an overcast day)they pop off out of place and kind of a PITA to stop and re-assemble them back together and pop back on the rods!!!! LOL's tjk
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I wrapped the "start rods" with black tape 4" up. It's a reference for my horizonal crosshair. As long as I'm on or slightly above those marks I know the chrony won't get killed! Also I don't use a target so my concentration is on the chrony. I just shoot into the woods.
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Thanks Ed! sounds like a great idea!!! So todays results with my new found knowledge:......
B28 .177 shooting 8.8 Beeman CroMag's in the 1250's fps= 30.54 FPE
B-28A .22 shooting 14.5 RWS Super-Domes in the 890's fps= 25.51 FPE
And the PowerLine 1000,...custom tuned by me!!, I call her my "Mini Talon Black Death" shooter.... throws 7.9 CPHP's at the 1040 fps range = 18.97 FPE!!!!!! Yikes. And I don't even care too much for these pel's!! This is according to the Pellet energy calculator in the library.
But being the doubting kind of fella I am,...I had to go with another "proof of power" test. I filled a few veggie cans with sand,...and shot them at 18 yards,...one or two shots in the mid to upper side of the cans layed them down off the 4X4 post I set them on. With the cans half full of sand and plenty of pel holes in the upper halves,...I just slid them off with a low shot. Water filled beer cans and bottles are a complete waste of time with these rifles!!! My oh my!!!! tjk
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For optimum accuracy and consistency in your chrony readings, do not under any circumstances shoot your chrony. 28.4 grain Eun Jin .22 pellet from a B50 does not help the LCD display, believe me.
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make a stand like Bob's, best thing you can do, I made one and a customer stole ...er...bought it for way less than it was worth. Need to make another....