R7 velocity?July 30 2008 at 2:16 PM
Mike (Login KF9VH)
What kind of velocity are you getting out of your .177 R7? I have seen in the past some claiming over 675. I am getting around 580 with cpl's.
While the advertisements claim 700 fps what are real world numbers?
Mike, I got my R7 back from Beeman after a "Supertune" by them.
|July 30 2008, 2:37 PM |
I've put about 2 tins through it. It was shootin JSB 8.4 g. Exacts at 635 FPS when I first got it back. The latest, after 2 tins, was JSB 8.4 g. at 615 FPS, Beeman Trophy 7.9 g. at 637 FPS. The JSB's seem to group best though.
|July 30 2008, 4:47 PM |
I had the Weihrauch HW30S which is the same rifle as the Beeman R7. I was getting 621fps with the 8.4gr JSB Exact (post lube tune). You can see my velocity chart at:
Typical for the HW30S/R7 is around 575-625fps with 7.9gr CPLs or 8.4gr JSB Exacts. The R7 is built as a very accurate plinker with similar velocity as a 10m target rifle. If you desire more power then the HW50S is the next step up the power ladder... then the HW95 (R9).
|July 30 2008, 4:56 PM |
spot on info
|July 30 2008, 10:37 PM |
R-7's vary somewhat in real world power, falling precisely into the range you noted at altitudes under 1000 feet. In many of the cases where low velocity is noted, the culprit can often (but not always) be the piston seal fit. The factory in recent years has been what I call "back grinding" the seals.. to reduce overall piston seal friction. The problem is: workers at the factory frequently take off just a bit too much material at the critical lip seal, and compression can suffer because of it. An R-7 clocking 575 fps with 7.9 gr pellets can sometimes be a struggle to tune up to just over 600fps due to other issues as well. RB
"The Universe is comprised mainly of two things.. hydrogen and ignorance."
Inventor, astronomer and metaphysical thinker.
|July 30 2008, 7:28 PM |
I just got a chrony and ran my R7 through it tonight. I'm really disappointed. CPL's averaged only 541 fps and JSB Exacts averaged 570 fps. I have a Maccari spring with the factory guide and a Tesla piston seal. When I put the seal in I had to sand the seal down because it was tight and really shooting slow. It looks like I need to take a little more off the seal to try to improve the velocity.
|This message has been edited by playinghooky on Jul 30, 2008 9:28 PM|
I know how you feel
|July 31 2008, 6:03 PM |
I have an old, pre-safety, R7 that's getting about 580 with CPLs. I'm still trying to get more out of it with spring, spacing, and seal sizing, but haven't got better than 580 yet. According to much, much, more talented airgun tuners and hobbyists, it should be able to get up there, but I haven't found the magic formula yet. Shoots nice, though.
Dan (in NY)
Not that high.
|August 2 2008, 12:00 PM |
Mine was shooting at 600 fps before tune, 640 fps after tune, and suppose to creep up another 10-20 fps after some shooting. Personally I wouldn't want it shooting any faster. Wouldn't be an R7 any more. Far as I'm concerned the 640fps is pushing towards the high. I could instantly tell after the tune that it was shooting harder. You wouldn't think 40 fps would make that much difference, but it did. At least in the R7. I think the original power of a rifle makes a difference. My PE was shooting faster after the tune, but I couldn't notice much of a difference in the shot cycle. Course it had been shot very little as the scope that came on it was moving with every shot so I wasn't all that tuned into its shot cycle before the tune.