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Joined: March 1st, 2002, 12:22 am

April 20th, 2012, 4:05 am #1


After getting everything going again, and ready to start the chrony, I found the pad I took all my Mrod notes on when I first got it.

Even with the offering of a fresh battery, the chrony refused to give up meaniful numbers. I have it down to lighting or anagle across the device. a 3000 psi fill gave me 48 shots, 13 of which gave a chrony reading

Guest apperance this evening was my Android running to noise meter apps. One program average 75 db, and the"high noise" was from 65 to 81 db. The other pgram agreed, but put the high number at 91 db.

8 shotsa of Beeman Wadcutters, no chrony data, starting fill 3100. I used the guage on the pump to fill to 3000. Gun gauge shows 3100 to start then to 2800

8 shots Exact Jumbo RS 13,43. no chrony, fill 2800 to ~2450

another 8 of the above, but got 671.9 and 684.2. mabye I didnt let the chrony warm up enough....

8 poly tipped Predators, gave 650.9, 718.8 and 721.4. fill was 2450, but I got distracked trying to get the chrony to cathc something I didnt record the next few fill numbers.....

8 Beerman Bearcubs gave 649.7, 640.3,652,4, no fill data

8 Beeman lasers gave 673.2, 669,9, 661,5, and her I beleive is the threshold of getting louder, 652.9 and 642.9. Had I bothered with a couple more shots, I think we'd have seen much more fall off for the next couple of shots. Fill on those was 1900 to 1500

I should the note the fact that when the gun made the shot at 652.9, it was a differenent sound. You could hear the valve making this loonnnngggg flatuent sound trhing to get enoughair out to drive the pel. I also believe, accoridn the very sketchiy evidence, that the other end of the shot string was valve lock.

So 24 to 36 shots, and this is a stock gun, nothings been adjusted.

 


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Joined: June 15th, 2004, 11:49 pm

April 20th, 2012, 12:48 pm #2

is so it might be giving you different readings.
First thanks for this information. now can I make a sugestion, not to bust your butt , but shooting a full fill with different pellets may not give you good readings. WTH ???
if you shoot one weight, say a flat, it may not shoot the same as say a domed , same weight espically with different tube pressures. OK, you see where I'm going.
When I did a string I filled the tube , shot a string, in my case 3 clips for a total of 24 shots, than an avg. refilled shot another string using a different pellet, same shots same fill pressure. all the time noting one clip, from another clip for pressure.

I know you wanted to get a base line for your gun, but shooting different pellets at different pressures may not give you a good base line. Make sense.
But, I like the readings you did get. A little higher than mine that I recorded , but I cant remember if my readings was my first gun or my second gun.

There is a optimal fill pressure for the PRod, which IIRC was posted at around 2600psi.

I looked for a sound meter app for my Iphone, but ratings on the ones availible were not all that good, so I dont have one. now using one on your phone, pad, may not get you accurate readings. you have to consider the senativity of mic on the unit giving you those readings. I once put a vid camera a few feet away from a muzzle and then out by the target to hear the sound difference. the sound was only as good as the mic and in this case not very good. shot blast noise and voice noise recorded very differently, but you also have to consider you hearing which mine is not the best.

Buster
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Joined: March 1st, 2002, 12:22 am

April 20th, 2012, 6:24 pm #3

cuz the first group was in the vavle lock zone.
My purpsoe in shooting several groups on one fill was to get speed and group data, neither of which happened yesterday.

I shot a lot of groups in the mrod of 5 shots of one pel, then 5 of another. But that was after I'd figured out the fill sweet spot et al. Still need to find that for the Prod...

I think the lights are causing most of my chrony issues, too much light or both sensors are seeing the same source. And I think the chrony is a shade too low. Both are easy enought to test and fix

I got homework it appears


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Joined: March 1st, 2002, 12:22 am

April 20th, 2012, 6:29 pm #4

is so it might be giving you different readings.
First thanks for this information. now can I make a sugestion, not to bust your butt , but shooting a full fill with different pellets may not give you good readings. WTH ???
if you shoot one weight, say a flat, it may not shoot the same as say a domed , same weight espically with different tube pressures. OK, you see where I'm going.
When I did a string I filled the tube , shot a string, in my case 3 clips for a total of 24 shots, than an avg. refilled shot another string using a different pellet, same shots same fill pressure. all the time noting one clip, from another clip for pressure.

I know you wanted to get a base line for your gun, but shooting different pellets at different pressures may not give you a good base line. Make sense.
But, I like the readings you did get. A little higher than mine that I recorded , but I cant remember if my readings was my first gun or my second gun.

There is a optimal fill pressure for the PRod, which IIRC was posted at around 2600psi.

I looked for a sound meter app for my Iphone, but ratings on the ones availible were not all that good, so I dont have one. now using one on your phone, pad, may not get you accurate readings. you have to consider the senativity of mic on the unit giving you those readings. I once put a vid camera a few feet away from a muzzle and then out by the target to hear the sound difference. the sound was only as good as the mic and in this case not very good. shot blast noise and voice noise recorded very differently, but you also have to consider you hearing which mine is not the best.

Buster
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I wasnt expecting much from it given the size of the mike and its primary purpose (voice). But both apps gave roughly the same data, and the fone sat in the same spot during that session.

I do have a real SPL meter, so I'll have to dig it out and dust it off. Hopefully it doenst use 9 volt batteries too.

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Joined: June 15th, 2004, 11:49 pm

April 20th, 2012, 9:35 pm #5

cuz the first group was in the vavle lock zone.
My purpsoe in shooting several groups on one fill was to get speed and group data, neither of which happened yesterday.

I shot a lot of groups in the mrod of 5 shots of one pel, then 5 of another. But that was after I'd figured out the fill sweet spot et al. Still need to find that for the Prod...

I think the lights are causing most of my chrony issues, too much light or both sensors are seeing the same source. And I think the chrony is a shade too low. Both are easy enought to test and fix

I got homework it appears


dr_subsonic's pneumatic research lab

the Lunatic Fringe of American Airgunning
Southwest Montana's headquarters for Airgunning Supremacy
Proud Sponsor of team_subsonic
Me, I usually shoot a string of pellets from a known psi to known psi. and with my Prod, I started out high like 3000psi and found the fpe leveled out about 26-2700 psi. so the next string I started at that point and most of the other pellets tested from that pressure seem to be right on.
shooting with different pellets on the same fill doesnt seem like it would get any thing because as the pressure drops the difference in pellets would affect the results. so shooting with one pellet, than another on the same fill, till you find the sweet spot of all pellets tested.
makes sense?


Buster
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Joined: March 1st, 2002, 12:22 am

April 20th, 2012, 10:07 pm #6


dont think changing pells will affect much, except POI, and even then if they are something the gun likes to eat, they should group well. Watching (and more importantly _recording_ the shot count and fill pressure... ahem...<img alt="happy.gif" src="/images/happy.gif" width="14" height="14"> ) when you start getting close to the "far edge" of the sweet spot you may see the "drop off" occur a little faster, or slower depending on the pel. As you use air the valve duration will change and thatw ill be true of any pellet you shoot, cuz every shot takes air from thetube.

the idea was to get several 4 shot groups of the pels I think the P-rod  may like, watch the air consumption and decide what pel to use. Doing it that way saves me some time and much pumping effort.
and the Post office tells me the HDD should be at home when I get there..... oh, more work......

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Last edited by dan_house on April 20th, 2012, 10:08 pm, edited 1 time in total.
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Joined: June 15th, 2004, 11:49 pm

April 21st, 2012, 1:41 am #7

who am I to say my way is better than yours.


Buster
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