Shot to Shot variation – what’s good enough?

[ora8i]

Shot to Shot from a PCP. This is not the PC power curve just the fluctuation between one shot and the next.

Example

600 ± 10FPS max to min of 20FPS
600 ±5 FPS max to min of 10FPS
600 ±2.5FPS max to min of 5 FPS

Very few of the top class PCPs can consistently manage to retune ± 2.5 FPS


So what do you all think?


I’m inclined to think ±10FPS is too much.


Regards Ora

[Hsing-ee]

Stick to a well lubricated, well sprung springer.

[kevG]

i think its a peace of mind thing,10 fps shot to shot consistency is plenty good anough,ive shot guns with around 20 fps s s c v and they have grouped just as well as 5 fps s s c v guns.must admit i like mine around 5 fps,but thats just a peace of minde thing,of course you can alow more variation on a .177 calibre as its a % thing.alot of fings aint tha

kevG

[99CLOMP]

Shot to Shot from a PCP. This is not the PC power curve just the fluctuation between one shot and the next.

Example

600 ± 10FPS max to min of 20FPS
600 ±5 FPS max to min of 10FPS
600 ±2.5FPS max to min of 5 FPS

Very few of the top class PCPs can consistently manage to retune ± 2.5 FPS


So what do you all think?


I’m inclined to think ±10FPS is too much.


Regards Ora

with.177 weighed pellets I get 40 SHOTS +/- 3FPS With a pcp, +/- 2fps with my springer unweighed= pcp=+/- 6fps, spring= 6 fps, i am happy with+/- 10fps in .177

[Raygun]

Hi Alan,
I'd be happy with the +/- 5 fpe.
With the variation in pellet weights you get in a tin you wouldn't notice it.

Unless your going to go to the trouble of getting it closer and weighing all your pellets I think a variation of 10fpe is O.K. Point of impact is going to vary very little.

ATB
Ray.

[verminhunter]

Shot to Shot from a PCP. This is not the PC power curve just the fluctuation between one shot and the next.

Example

600 ± 10FPS max to min of 20FPS
600 ±5 FPS max to min of 10FPS
600 ±2.5FPS max to min of 5 FPS

Very few of the top class PCPs can consistently manage to retune ± 2.5 FPS


So what do you all think?


I’m inclined to think ±10FPS is too much.


Regards Ora

Perfect,nothing wrong at all with 10fps variation,iwont shift your poi one bit.Yes you can say there's better like 3fps or 5fps but so what? anything like 20fps and 30 fps then you might want to have a look at the rifle but 10fps is perfectly fine mate dont worry.

[ora8i]

I’m setting up my Raider, I probably getting about ±3 FPS variation but I’m using these figures to work out the length of the heart of fill.

http://www.ora8i.rivington-riflemen....end%20line.gif

and showing just the trend lines for 3 different transfer port IDs

http://www.ora8i.rivington-riflemen....rend-lines.gif

and from the trends

Working off the Trend Lines the curve for the 2.2 mm ID transfer port is obviously the worst and I have discounted it.

Results for the 2.2mm ID Transfer Port

• About 44 shots within ± 5FPS
• About 30 shots within ±2.5 FPS

Results for the 2.0mm ID Transfer Port

• About 77 shots within ± 5 FPS
• About 46 shots within ± 2.5 FPS

Results for the 1.8mm ID Transfer Port

• About 84 shots within ± 5 FPS
• About 53 shots within ± 2.5 FPS

I think this will get burried so I'll start a new thread about calculating shot to shot variance on a curve.


Regards Ora

[Scooby]

You aren't gonna notice the difference if you get a total variation of 15fps over a charge/course of fire. My Mk3 gives 150+ shots with a total variation of 10-15fps, my Walther Dominator gives 100 shots with a similar variation.

[HarryPotter]

I was always led to believe that anything under a 25fps deviation is perfectly acceptable for target work.

[Brian.Samson]

Variation at the muzzle isn't the important factor. It's downrange where it counts.

A large variation at the muzzle can be an indicator of a potential problem, but if the gun groups well at the distance you want to shoot at, then forget the chrono readings.

Very often with too much chrono'ing you can end up chasing a problem that doesn't exist ( and they're the hardest to cure )

[Herx77]

Shot to Shot from a PCP. This is not the PC power curve just the fluctuation between one shot and the next.

Example

600 ± 10FPS max to min of 20FPS
600 ±5 FPS max to min of 10FPS
600 ±2.5FPS max to min of 5 FPS

Very few of the top class PCPs can consistently manage to retune ± 2.5 FPS


So what do you all think?


I’m inclined to think ±10FPS is too much.


Regards Ora

Nice to be within a small tolerance range, but what does it do on the range. One does not ensure the other? Better to ensure accuracy than paper results. color=red] HERX77 [/color]

[Shed tuner]

plus or minus 10 and I don't get worry

Most of my gun s(springer or PCP) give a total variation of about 15fps, (plus or minus 7.5 fps), and all group veryy well..

Go with the 2mm port

[ora8i]

Planning to go with the 2mm and reduce the pre-load a bit.

How has the Falcon with the soldered port stood up to prolonged use? It’s solder job that is in it now but I have managed to get a bit of Brass in case the solder doesn’t last.


Regards Ora

[Fluffybuck]

I look for about +/- 1% velocity (+/-2% energy).
Equating to:
.177: 800ft/sec: within +/- 8ft/sec
.20: 700ft/sec: within +/- 7ft/sec
.22: 600ft/sec: within +/- 6ft/sec
.25: 500ish ft/sec: +/- 5ft/sec.

Just my thoughts......

[Scooby]

Planning to go with the 2mm and reduce the pre-load a bit.

How has the Falcon with the soldered port stood up to prolonged use? It’s solder job that is in it now but I have managed to get a bit of Brass in case the solder doesn’t last.


Regards Ora

Have you tried Silver Solder, it will stand the blast no problem.