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Old 16th February 2012, 09:18 AM
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maestro maestro is offline
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Join Date: Nov 2009
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Originally Posted by Matt View Post
I don't recall you measuring the distance from muzzle to microphone but believe you when you say you did.
Believe me Matt, I've measured the muzzle-mic distances, everybody can remember who has shot for me. This is what was that small measuring tape for. I recorded for every rifle the following datas: muzzle-target, muzzle-microphone, pellet type, chrono readings.

Originally Posted by Matt View Post
If you tested a rearwards venting muzzle break as opposed to a forward venting break surely the perceived shot would be faster in the rear vented break?
I can see already what is your problem but please read carefully the description of the experiment: I didn't calculated with the sound of the shot at all, so it wasn't relevant how the sound comes out from the rifle. Some rifles didn't even have a noticable shot sound anyway. The microphone was in contact with the action and measured the time between two very definite points:
1. from the first sound of the mechanical parts
2. to the reflected sound of the hit on the target
As you can see, the sound from the muzzle wasn't used at all.

Anyway, for some rifles where I was able to separate the sounds better, I made some calculations with it:
1. time from start to the muzzle sound = lock-time + sound travel on muzzle-mic way.
2. Time from start to the reflected muzzle sound = lock-time + sound travel from muzzle to target + sound travel from target to microphone
Both of these alternative method gave nearly the same results as my main method but with more variation - maybe exactly because of the different air brakes as you mentioned.

About the muzzle position: most of the times we could see it, or did know that 2-3 cm range where it has to be (after the grub screw and before the first venting hole and/or separator cone). If I estimated the position of the muzzle with 3 cm difference from the reality (this is the maximum I think), this would have changed the lock-time result with 0.14 ms, far inside the overall tolerance of the experiment.

Originally Posted by Matt View Post
Good work by the way, I just question validity of the results this is not to say I doubt them.
No problem Matt, I designed everything very carefully and don't think that there would have been serious mistakes in my method but everybody can better trust them if we can see that the doubts have no real grounds. As I said already, a 0.5 ms difference is coded into the methods because they've been done not in a laboratory - but not more. This means that the Ripley may had a lock-time of 5.1 ms while the Walther 5.9 and the reputation of Ripley is already saved

If you want more results with Ripley then please measure very precise those two distances which I've asked in the NEFTA WL9 thread and then we will have one more Ripley measuring...
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