air stripper tests [part one] ...

[slugger]

well i got a chance to do a spot of shooting today, time to test the airstripper [thanks neil] ...
i spent an age setting up a 100 yard set of targets... and began sighting-in........very quickly it was apparent the wind was too much for this range today [some shots being blown off the A4 sized paper targets altogether] and so i reset everything up at 55 yards
onto the targets themselves........ 3 to be exact, 1-with air stripper..2-bare barrel [cone removed from stripper] ... 3-with the standard hw silencer !
i set them up all 3 in a row, i didnt want to go back and forth with fresh targets as this would be time consuming, and possibly skew the results [change in weather if left too long maybe].

pellets used were jsb exacts in 4.51 flavour [8.4g]
the field dropps away slightly, so the targets are of a lower elevation than the shooting spot.
due to not wanting any "other input" from the missus, both verbal and wobble i set her up shooting off the trailer, and i used the bonnet of the truck as my perch.
the front of the rifle was sitting on a fully adjustable bipod, and the stock was resting on 2 life-jackets [soft and foamy] with a purpose made wedge of wood between the lifejackets to adjust elevation
now the downside of todays test was the wind ! ideally a perfectly calm day or better still a 100 yard indoor range would have been better, but you know what ? today was typical in terms of outdoor shooting, a breeze, with minimal gusts...... so altho not perfect for making hasty conclusions regarding an airstrippers ability to improve groups, it was at least representative of an average days shooting in the uk i feel !

for the wind reasons mentioned above i am calling this "part 1" .... at some later point when we have a properly calm day i shall retest for more conclusive results.
its important to mention i did my utmost to keep all 3 groups as fair as is possible with the given circumstances, for example i used pellets straight from the tin........and all pellets used from that one tin.
i settup the gun with a bubble-level to eliminate 'cant'..... and i made sure the gun was sat in exactly the same spot [self supported with no contact from me] for all shots. the only part i touched was the trigger !

i have a few pics i could email to someone if interested [as i dont have a photo hosting thingy-mabob, and im sure the agro in sorting one out would get the better of me [bit of a pooter-phobe]

anyways i shall try to verbally explain the groups..
firstly i decided to read more into the vertical axis of the groups [height from lowest to highest poi] purely because of the wind making the horizontal axis less conclusive and so i shall describe the groups with that in mind.. for ease of visualisation i have drawn a box around the groups so i have straight lines to measure from [lines drawn outside of the pellet holes not through them].

group 1 [with the airstripper] ... this box measures 23.5mm high.. by .... 47.9mm wide

group 2 [with cone removed/bare barrel]... this box measures 32.5mm high ..... by ...... 70.1mm wide

group 3 [with the standard HW silencer] ... this box measures 43.7mm high ...... by ..... 30.1 mm wide

now its difficult to describe, but what quickly becomes apparent is that the group with nothing on the barrel, no stripper, no silencer, was the largest !! by a noticable amount , this would suggest to me that the standard silencer [this group being smaller] must not only do a very good job at keeping things quiet [pcp's are quiet loud un silenced] but the innards of the silencer must be doing something to calm the blast wave of air ?
lastly the stripper group....... this had the smallest overall group [just] but most importantly i think, this group showed the smalles vertical axis measurement ! so, if we 'somewhat' ignore the horizontal axis of the groups for a moment due to speculative wind changes [yes i realise the poi can change vertically too, but i think we can all agree much less-so than horizontal] then it is quickly apparent the stripper works !
no i have no idea how. its probably dynamic stability aswell as the obvious 'stripping' of blast-air for all i know.....
i dont have the right chrono for velosity testing [a combro at 55 yards on a windy day isnt going to last long] so cant give any imput into that side of things........and as already mentioned this test mustn't be taken as pure scientific statistics, the wind is too big a variable to ignore.. that said, i genuinly believe group-sizes can and will be reduced thanks to the air stripper....... so much so that its the amount or percentage thats left unanswered only -in my mind
seb

[Gwylan]

Careful...! You're in danger of turning into a geek, or even worse, a nerd!!!
A few things, how many shots in a group? (The more the merrier, the odd flyer you can discount, or put down to shooter error. Did you refill between change of target? I'd have weighed the pellets myself.
You're welcome to borrow my Pal chrono, it really makes a difference. (You break, you pay..!)
perhaps we could meet up at Trago? PM me if you're interested.

Gus

[slugger]

a geeky nerd eh... yeh i can live with that .. the groups were 14 shots each [i tried to do it fairly swiftly to keep the timeframe sencible incase of weather conditions changing]
i cant wait for a proper calm day and re test out to 100+ yards....... but in truth i am already convinced the stripper is of benefit

[Waisted]

Interesting post, I like things geeky. Could I ask which rifle were you testing with and do the air strippers help to reduce noise.

[slugger]

this was my modded hw100 .. and no, strippers dont do a lot to supress noise dont get me wrong, its not quite as loud as bare-barrel.........but its no where near as quiet as the hw silencer. so a stripper is probably not gonna be a hunters best friend, that said, if it help increase your kill-zone range, then maybe it is ?

[air-tech]

Technically, to test a stripper you need to compare with a device that is the same basic shape and weight as the stripper but which does not have any "stripping" function.

The results are odd probably due to wind and the weights of the devices, I can understand a different group size but that one device supposedly has an effect on windage and the other on elevation tends to indicate that both the weights of the devices and the variable wind are having an effect on group size (and shape) that is by far greater than any effects that are as a result of the intended purpose of the device.

This is not a for or against vote for strippers, just to indicate that to test and compare the performance of anything you need to completely eliminate all other variables.

[slugger]

granted buddy, but i tried [when zero-ing] the stripper without the cone-insert and just the bare barrel [group size was identical] so for the actual test i just left the stripper on [but removed the cone] for the bare barrel group [so that the weight was similar on the end of the barrel]
now i know i could have been more scientific , weighed the pellets, pushed them all through my pellet sizer.. etc etc........ but i knew this level of anal err 'ness' would be pointless given the wind today...
dont get me wrong, when i do the calm day test at 100+ yards i will allow myself all day to do every little minute thing i can to test perfectly... however, todays basic test indicate [to me at least] the stripper was beneficial........
more conclusive testing to come , watch this space... or more realistically i wont be able to find "this space" in the future, so watch out for a new space instead