tinkering with airguns is fun

[triggertreat]

Yes. Impressive.
That yields 2719 total FPE from 215 cc (13 cu in).


Now where is that efficiency calculator?


Hunter

Would need to know the air pressure start/stop and the plenum volume to calculate the efficiency accurately.  Showing 3 just guessing at psi used.  ES is certainly good.  He's really showing what the FT can really achieve.

As far as start/stop pressure it was around 3000 starting and 1500 stopping, not sure what plenum size would be.

I would say you calculated the efficiency correctly or at least close enough.  My chart came up with 2.0.

[lm22]

Yes. Impressive.
That yields 2719 total FPE from 215 cc (13 cu in).


Now where is that efficiency calculator?


Hunter

Would need to know the air pressure start/stop and the plenum volume to calculate the efficiency accurately.  Showing 3 just guessing at psi used.  ES is certainly good.  He's really showing what the FT can really achieve.

As far as start/stop pressure it was around 3000 starting and 1500 stopping, not sure what plenum size would be.

I would say you calculated the efficiency correctly or at least close enough.  My chart came up with 2.0.

Nice, as I was shooting the string I was nailing a 5/8in spinner I made, set at 50 yards, every shot slung at it. Something like 40 shots of the string. Also consistently nailed a 3/4 in spinner at 75. So far it's panning out to be a pretty solid shooter. Seems as long as the wind isn't getting the best of it I'm the main reason groups open up more than a moa out to that 75 yard mark. Haven't shot it much at 100 yards since I started modding, but the little I have I've seen a few 1-1.5 in groups on steel so we'll see. Hopefully I can get a nice calm day to test it out. Lots of variable days recently.

[lm22]

Yes. Impressive.
That yields 2719 total FPE from 215 cc (13 cu in).


Now where is that efficiency calculator?


Hunter

Would need to know the air pressure start/stop and the plenum volume to calculate the efficiency accurately.  Showing 3 just guessing at psi used.  ES is certainly good.  He's really showing what the FT can really achieve.

As far as start/stop pressure it was around 3000 starting and 1500 stopping, not sure what plenum size would be.

I would say you calculated the efficiency correctly or at least close enough.  My chart came up with 2.0.

re-did my math and got 2.006 FPE/CI also what did you use to get that graph?

[triggertreat]

Yes. Impressive.
That yields 2719 total FPE from 215 cc (13 cu in).


Now where is that efficiency calculator?


Hunter

Would need to know the air pressure start/stop and the plenum volume to calculate the efficiency accurately.  Showing 3 just guessing at psi used.  ES is certainly good.  He's really showing what the FT can really achieve.

As far as start/stop pressure it was around 3000 starting and 1500 stopping, not sure what plenum size would be.

I would say you calculated the efficiency correctly or at least close enough.  My chart came up with 2.0.

re-did my math and got 2.006 FPE/CI also what did you use to get that graph?

I created the spreadsheet and am sharing it for free here on the GTA.  It is Windows based so you will need a PC and a recent version of Excel to use it.  It will store 20 strings and you can compare up to three strings at a time.  It also has other useful features.  Feel free to download a copy along with the tutorial video to help you get started with it if you want to check it out.

https://www.gatewaytoairguns.org/GTA/index.php?topic=146784.msg1545959#msg1545959

[lm22]

Yes. Impressive.
That yields 2719 total FPE from 215 cc (13 cu in).


Now where is that efficiency calculator?


Hunter

Would need to know the air pressure start/stop and the plenum volume to calculate the efficiency accurately.  Showing 3 just guessing at psi used.  ES is certainly good.  He's really showing what the FT can really achieve.

As far as start/stop pressure it was around 3000 starting and 1500 stopping, not sure what plenum size would be.

I would say you calculated the efficiency correctly or at least close enough.  My chart came up with 2.0.

re-did my math and got 2.006 FPE/CI also what did you use to get that graph?

I created the spreadsheet and am sharing it for free here on the GTA.  It is Windows based so you will need a PC and a recent version of Excel to use it.  It will store 20 strings and you can compare up to three strings at a time.  It also has other useful features.  Feel free to download a copy along with the tutorial video to help you get started with it if you want to check it out.

https://www.gatewaytoairguns.org/GTA/index.php?topic=146784.msg1545959#msg1545959

Sweet! Thank you much!

[lm22]

Getting so many shots per fill now I'm either going to have to start spending more on ammo, forcing myself to not shot an entire fill in one session, or start shooting less often. Going through ammo like a wild fire.

[lm22]

For a little more accurate efficiency calculation.

Starting fill: ±3050 psi
Stopping fill: ±1450 psi
total psi used: ±1600 psi

1600psi/ 14.5 = 110.345 bar
110.345 bar x 13.1 CI = 1445.517 std. CI
2719 FPE/ 1445.517 CI = 1.88 FPE/CI

[lm22]

There's something else I did that I'm surprised I forgot to mention. I drilled several 1/8in holes around the outer edge of the hammer and plugged them with derlin. I then shaved the derlin down to be a hairs width larger than the hammer. This not only helped with my binding issue I was having, it also improved the smoothness of cocking. I'll get photos when I can.

[triggertreat]

There's something else I did that I'm surprised I forgot to mention. I drilled several 1/8in holes around the outer edge of the hammer and plugged them with derlin. I then shaved the derlin down to be a hairs width larger than the hammer. This not only helped with my binding issue I was having, it also improved the smoothness of cocking. I'll get photos when I can.

A good idea!  The knobs on mine are adjustable with hex screws.  I still prefer the MDS hammer overall for the lighter weight and cocking smoothness.

[lm22]

I like that ! Very clean! Mds hammers seem like a great option, especially for regulated setups. I was looking at the light weight mds/ ssg that is for sale on airgun revisions before I decided to go the diy route. I definitely saved a lot by doing so.

[lm22]

At the cost of some efficiency and some FPS I improved consistency.

[triggertreat]

Those are awesome numbers on a great tune.  About all you can probably do now is set a small delay between each shot so the reg can fully reset/refill and maybe weight sort your ammo for even more consistency.  I don't think the FT has much of a reg plenum though.  It looks like you came off the reg at shot 75 and put in a small bell curve.  That's a sign of a well-tuned regulated gun.

I'm not sure why your chart is not highlighting all of the max velocities but glad you are getting some use out of it.

[lm22]

Those are awesome numbers on a great tune.  About all you can probably do now is set a small delay between each shot so the reg can fully reset/refill and maybe weight sort your ammo for even more consistency.  I don't think the FT has much of a reg plenum though.  It looks like you came off the reg at shot 75 and put in a small bell curve.  That's a sign of a well-tuned regulated gun.

I'm not sure why your chart is not highlighting all of the max velocities but glad you are getting some use out of it.

Thanks! Definitely not much of a plenum on the F&T. I think you are right about coming of the reg at 75 and will probably stop shooting there most sessions. While it stays pretty consistent, might as well save the ammo unless I'm having too much fun to stop. I want to try weight sorting my pellets just to see what happens. However, I have yet to be able to find a good scale that doesn't change its reading for the same pellet by .3 grains or more every time I weigh it.

Probably entered something in wrong to the chart or something. It's making it a lot easier to keep track of things though so thanks again for providing it to everyone.

[triggertreat]

Those are awesome numbers on a great tune.  About all you can probably do now is set a small delay between each shot so the reg can fully reset/refill and maybe weight sort your ammo for even more consistency.  I don't think the FT has much of a reg plenum though.  It looks like you came off the reg at shot 75 and put in a small bell curve.  That's a sign of a well-tuned regulated gun.

I'm not sure why your chart is not highlighting all of the max velocities but glad you are getting some use out of it.

Thanks! Definitely not much of a plenum on the F&T. I think you are right about coming of the reg at 75 and will probably stop shooting there most sessions. While it stays pretty consistent, might as well save the ammo unless I'm having too much fun to stop. I want to try weight sorting my pellets just to see what happens. However, I have yet to be able to find a good scale that doesn't change its reading for the same pellet by .3 grains or more every time I weigh it.

Probably entered something in wrong to the chart or something. It's making it a lot easier to keep track of things though so thanks again for providing it to everyone.

Well as long as the ES stays within your goals for your distance there's nothing wrong with continuing on pass the reg set point.

You may try and download the file again.  It should work as is.  Also, in the top left corner of the graph is a pulldown where you can manually adjust the upper and lower limits of the left axis to better display on the chart.  Or you can just use Auto Exec which is what Excel thinks the chart should look like, which sometimes I don't agree with and is why I put that in the chart.

This is the scale I use for sorting.  I really like it for the price.  It seems to be very stable and has a large display.

It is an AMIR Digital Milligram Scale, 50g Portable Mini Scale, 0.001g Precise Graduation, Professional Pocket Scale with 50g Calibration Weights Tweezers (Batteries Included) found on Amazon.  I can't seem to post the link.

[lm22]

Thanks for the scale recommendation. I'll look around for it.

[HunterWhite]

Please note that these little scales are so sensitive that ceiling fans will give you fits. The air conditioner or heater will also.


HTH


Hunter

[triggertreat]

Please note that these little scales are so sensitive that ceiling fans will give you fits. The air conditioner or heater will also.


HTH


Hunter

So true.  Don't breathe hard in its direction either, lol.  I keep fans off.  It does come with a hood which helps but I don't like using it except for testing the difference sometimes.  I love the sensitivity of the scale though.  Also, the scale must be on a very flat surface.

[lm22]

Please note that these little scales are so sensitive that ceiling fans will give you fits. The air conditioner or heater will also.


HTH


Hunter

Will keep that in mind thanks.

[lm22]

some 50 yard groups

wind: 2-3 mph from 2 o'clock

[lm22]

more groups

wind: 4-5 mph from 2 o'clock