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+--- Thread: SMK 107 and EC Tuner/Brake testing (/showthread.php?tid=428)
SMK 107 and EC Tuner/Brake testing - KenC - 08-22-2021
Finally made it to the range this morning. My main reason was testing the SMK 107gr(1.697" CBTO/.010" off the lands) under 28.3gr of LVR with the new EC Tuner/Brake. I can tell you it does work. Expensive, but it works. Started at 0 setting on the tuner and the group was large as was 1 and 2. Started to shrink at 3(nice group and probably opened up 1 shot due to me) with 4 at .412 MOA. Shot this setting twice(forgot to reset) and same result. 5 opened to .5 MOA and 6 went to .6 MOA. 7 opened way up again. So, I had twelve shots consecutively at .6 MOA and below. Avg velocity was 2712. I had settled on the 28.3gr from a few weeks earlier at 95+ degrees(about 85 when shooting today) out and it was at 2745 AVG. IMHO, this is near max for this bullet/powder combo as I am seeing some ejector swipes. Using CCI BR-41 primers and Hornady brass. Only problem with the EC Tuner is it is too large to get the Magnetospeed to work right as I can't get it close enough. I had to take off the tuner to test the velocity. Oh well. I think I can get it better and more testing to come.
RE: SMK 107 and EC Tuner/Brake testing - grayfox - 08-22-2021
Long as you keep the tuner vernier setting, doing the chrony with it off won't change the MV much if at all.
IMO one reason the tuner works (and only an opinion as I have not tested it myself) is that it changes the horizontal tuning/timing of the pressure wave, for timing like Chris Long discovered in his papers on optimal barrel timing. The brake aspect doesn't hurt either, but being able to tune the length with what is effectively a vernier adjustment is an advantage for you. The longitudinal wave is running at 18,000 ft/sec, so in the microsec's up and down the barrel.
I pretty much use jam nuts for my brakes now and don't use any loctite (and NO crush washers!) to speak of; the jam nut keeps it on fine and it's not going into battle so I'm good with it.
RE: SMK 107 and EC Tuner/Brake testing - KenC - 08-22-2021
(08-22-2021, 07:54 PM)grayfox Wrote: Long as you keep the tuner vernier setting, doing the chrony with it off won't change the MV much if at all.Yes. Much easy to tune it this way. I understand about the jam nuts and not using the crush washers. The tuner has 3 allen screws which you can lock down to keep you settings. Very easy to loosen and adjust for another combination. I have all of my settings and loads in a data base, so can easily return to a certain setting.
IMO one reason the tuner works (and only an opinion as I have not tested it myself) is that it changes the horizontal tuning/timing of the pressure wave, for timing like Chris Long discovered in his papers on optimal barrel timing. The brake aspect doesn't hurt either, but being able to tune the length with what is effectively a vernier adjustment is an advantage for you. The longitudinal wave is running at 18,000 ft/sec, so in the microsec's up and down the barrel.
I pretty much use jam nuts for my brakes now and don't use any loctite (and NO crush washers!) to speak of; the jam nut keeps it on fine and it's not going into battle so I'm good with it.
RE: SMK 107 and EC Tuner/Brake testing - popgun - 11-23-2021
Yes, what barrel length? I'm getting 2685fps with 28.7 of lever out of a 22" barrel using 105 gn Hornady BTHP in a gas gun. Also at .010" jump. I also have a EC tuner brake. I beveled the mount on the magnetospeed to go further forward on the barrel and slightly onto the brake. Works great and still works on other barrels..