Reply With Quote15-20 is probably enough. I'm sure there will be a statistical claculation for this, and IIRC, 14-15 is the minumum to get a reliable spread.Originally Posted by cooper_dan
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Serious question.
How many shots would you want to see for a gun review? Currently writing up a review for the Hatsan 200W. Was planning on a 30 shot group (compared to a 30 shot group with my TX). The idea being over an HFT course you would want 30 good shots. Too much?
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15-20 is probably enough. I'm sure there will be a statistical claculation for this, and IIRC, 14-15 is the minumum to get a reliable spread.
Always looking for any cheap, interesting, knackered "project" guns. Thanks, JB.
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If it's got a magazine the group is a full mag, because that way any tolerance/differences as the mag rotates will be shown.
Single shot groups should be a min of 5 shots to count for anything.
For a review I'd expect at least a full fill of air for a PCP, or a couple of hours worth of plinking with a single shot, But surely a decent review would be done as several sessions over a couple of weeks just in case it's the shooter having a good/bad day rather than the rifle.
Last edited by angrybear; 31-12-2017 at 08:39 PM.
"FETCH IT THEN!!!!"
No., Not nonsense..... Let me explain...
You know a group is pants of the first 3 are all over the place & you have done your bit.. and in a similar guise you have to do the first 3 of any 10 shot group well to make a good 10 shot group
"corners should be round"Theo Evo .22/.177 - Meopta 6x42, DS huntsman classic .20 vortex razor LH 3-15x42 under supervised boingrati tuning by Tony L & Tinbum, HW77 forest green - Nikon prostaff 2-7x32 plex.
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Like several have said, for pellet testing, 5 shots to get initial results, then further tests, I use either a mag full or 10 shot groups, I find that greater than 10shots can create just a large hole in the target, bad enough when 10 shots give a 15 mm group.
My own thoughts are that the size of group and the distance they're shot at, I use a 30 yards range (longest I can safely get in my garden) and 5 shots minimum, and I'm not satisfied if a pellet doesn't group to smaller than 17mm at that range, I know that some are happy to group to 1inch at 10yards, and others want 10mm at 55 yards, just everybody's got their own 'ideal' measurement
may also be employed in conjunction with a drawn reciprocation dingle arm, to reduce sinusoidal repleneration
[QUOTE=Rickenbacker;7403476]
In the end I got a job driving a forklift at a hauliers. I can stack pallet on pallet all day long and get paid for it now.
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3's are ok BUT you need a statistically significant number of groups not just one group of 3. Even so a 3 shot group is better than nothing.
ora
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There is getting on paper, getting to centre. Three shots groups does that, heck even two. Walk them in.
Once on target then the zero takes place. Here five helps to adjust zero. Done several times given a break between strings. Once it starts jumping either side then you are pretty much there.
Final check zero I like to do at least 5. Depends how expensive the ammo is. In the military we did ten, but weren't paying for the ammo. Even twenty. This confirms zero and expected spread in the field. If it keeps it "all there" then its good to go. If it ends up bigger than wanted then thats gunsmithing and ammo loading. What can you live with at point blank ranges?
And then there is group checks for drop which requires 5 as a minimum at each range if not 2x5.
Once zeroed for that day, do it again with a repeat check on another day. If its behaving then they should go where they did last time out. If they don't you need a check zero again in another weeks time. Eventually if the rifle combination and ammo is up to it you have a practical zero that never changes; and anything else is the conditions of the day. How many times have you done two clicks, only to click them back a day later? Once found it takes several shoots "out", or shift of POI, to question the zero. I have rifles that are on the same zero for years, using the same ammo. Too often I've done a quick zero, thought rubbish, concentrated and back in the middle they go.
A ten shot group shows what can be expected in the field, not a few lucky ones. Theory of the group and all that.
A box of Centrefire ammo is the same as one driven pheasant at full cost. Just the way it is.
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A 5 round group is enough In my opinion a 10 round group you are more likely to tire and potentially ruin your grouping.
If a 5 round group isn't enough for you then rest after the 5 then do another 5 round group on a fresh target, best of both worlds then.
Regards
Martin
Registered User
Ha ha, do you both remember the thread, with the guy stacking 3 pellets on top of one another, resting on a fence post from a boggy ditch?Oh I remember it alright. One of the classics.
On the new 2018 version of Chairgun there is the 'Boggy Ditch' option. For targets at various distances you just adjust the time that you stand in the boggy ditch. The longer you stand the more you sink and thus the rear end of the rifle drops and the elevation is increased for longer targets. So for close targets you aim bang on and release immediately. For longer targets you wait longer and release when the time equals the distance on the graph. Eliminates the need for Mil Dot scopes.
There are a number of factors that have to be taken into consideration when testing groups with air rifles ...
If you are a hunter that posts on the internet then there is no need to ever practice groups on paper or card. Most air rifles, in particular springers, that are used for hunting, group totally different when shooting at paper or card. So, although you may find that when you try and shoot groups at paper/card you struggle to get any sort of decent group, when that rifle is used on a live animal you will make an instant kill every time. Also, hunting rifles ( again strangely mainly springers ) must never be used on a HFT course. The barrels fitted to these rifles are specifically made to kill quarry at up to 70 yards, but will be useless at trying to hit knock down targets on a Sunday morning.
Never shoot that last pellet in a group ... it's always that one that f***s it up ( There's actually some real psychology in that
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Dan
You'll know where I'll go with this!
I mentioned it in a recent thread. I seriously think shooting 30 shots from a single repeated position is totally pointless if assessing the rifle for HFT use ( springers ).
You know, I actually thought about this a couple of days ago following mine and your comments on that other thread.
I have acquired permission on a local Country Estate, confined to within the grounds of the cricket ground. Absolutely perfect for doing testing with a modern day pavilion, with loos, a kitchen and heating. Park right next to the pavilion etc. Five minutes from home. Miles away from anywhere. No one there during midweek days and all over winter. Just me, my dog, an air rifle, a few rabbits and the buzzards. Luxury.
There are a few trees on the ground that would be perfect for setting targets at various heights and targets and shooting positions can be placed for 360 Degree wind. It's air rifle testing heaven.
I took the dogs for a wander and I was looking at the venue and thinking that I could do some springer 'HFT' testing there. I was thinking along the lines of a test that included shooting groups in a comfortable HFT Prone position at various ranges ( to test basic grouping ability ). Then incorporating 'Up the Peg' and also incorporating targets at various angles of elevation ( targets in tree ). To test that springer in true course mode HFT. It could be a set test that can be repeated.
I wasn't thinking of using different rifles, as such, like I think you are suggesting in your trials, but using one of my HW77k's and testing it in different guises to see which gave the best option re hold sensitivity, POI shift, tightest groups etc. Using the same stock, barrel (main tube)/underlever/action/trigger unit/scope/mounts, I could easily exchange different tunes as one comparison. Then leave the same ( best ) tune and try different things like barrel weights on/off, weight in rear of stock yes/no ... and so on.
I really must try and do it. Good luck with your tests but I do think you need to try and simulate a HFT course to truly test if a model of springer would be a decent HFT option. You may find a cheap springer does quite well and shoots tight groups from a similar HFT style prone position and that is then recommended to newcomers as a good, cheap, starter option. When used in varied positions it may be a shotgun and be a disappointment to the user.
Last edited by bozzer; 01-01-2018 at 11:41 AM.
Zebedee
Haha!Oh I remember it alright. One of the classics.
On the new 2018 version of Chairgun there is the 'Boggy Ditch' option. For targets at various distances you just adjust the time that you stand in the boggy ditch. The longer you stand the more you sink and thus the rear end of the rifle drops and the elevation is increased for longer targets. So for close targets you aim bang on and release immediately. For longer targets you wait longer and release when the time equals the distance on the graph. Eliminates the need for Mil Dot scopes.
There are a number of factors that have to be taken into consideration when testing groups with air rifles ...
If you are a hunter that posts on the internet then there is no need to ever practice groups on paper or card. Most air rifles, in particular springers, that are used for hunting, group totally different when shooting at paper or card. So, although you may find that when you try and shoot groups at paper/card you struggle to get any sort of decent group, when that rifle is used on a live animal you will make an instant kill every time. Also, hunting rifles ( again strangely mainly springers ) must never be used on a HFT course. The barrels fitted to these rifles are specifically made to kill quarry at up to 70 yards, but will be useless at trying to hit knock down targets on a Sunday morning.
Never shoot that last pellet in a group ... it's always that one that f***s it up ( There's actually some real psychology in that
A classic on a classic. Nice one!
By the way, after all that stress and tension of whether that last shot will open that group up.....isn't it nice when that last one's a perfect one?
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NEXT EVENT :- May 4/5, 2024.........BOING!!
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maybe with a springer but the full mag of 12 from the Rapid takes less than a minute, hardly likely to tire doing that
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hsing-ee,
IIRC, seventeen (17) or nineteen (19) points are need for estimation of a Gaussian curve area.
Fewer data points can be used, but the error is in the estimate will be larger, so the predicted n-shot group will also be bigger.
Shooting ten (10) or more ten (10) shot groups will tell you most of what you need to know.
Have fun
Best regards
Russ
Registered User
When we were at UNI we were told that a minimum of 7 sample points are required to make a valid statistical graph in our measurements. I guess that you could apply the same logic to our pellet testing.
A.G
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