Hi All, I did some initial testing with a new 280AI barrel. Below is the order of testing with no cleaning between.
59.0gn 2213 produced a 5 shot 6mm group at 200yds ES 21f/s 2870av 59.5gn 2213 gave a 5 shot 19mm group at 200yds ES 15f/s 2890av 60.0gn 2213 gave a 5 shot 22mm group at 200yds ES 14f/s 2900av 59.0gn 2213 gave a 4 shot 10mm group at 200yds ES 28f/s 2880av
weird how the groups got bigger as ES got smaller?
I realize it's only 200 yds but an explanation would be good.
Last edited by Tim N on Mon Aug 15, 2016 9:50 am, edited 1 time in total.
We don't rise to the level of our expectations, we fall to the level of our training. Archilochos 680-645 BC
Tim did you shoot two groups at 59gr or is that a mistake? Small samples are good for identifying loads that can give a higher ES. Like Dave Mc says do it again and the results will probably be different. Steve
Hi Graham, Thanks for the advice... I have done the initial testing without the tuner and when I find a happy place for it I will fit the tuner and test further.
We don't rise to the level of our expectations, we fall to the level of our training. Archilochos 680-645 BC
5 shot groups or velocity ES/SD cannot show the picture - please review the variation I posted in the recent thread on sampling issues. No conclusions can be drawn due to the random distribution of velocity and shot position within our population. You will always get natural variation of the size you are describing from one group to the next with exactly the same load. You will hear statisticians say you need 30 shots minimum in each variation. I proved recently using a monte carlo simulation that averages (aggregates or other) of 6*5 shots or 3* 10 is almost as powerful and much easier for shooters to accommodate without the secondary effects of shooting 30 shot strings (or 150 (EDIT 120) in this case). None of these groups or sd variations can be said to be any different to each other unfortunately but may give you and indication of where you would like to "test" with some 10-12 shot groups and you need 3 of these or more to start gaining confidence in your load/rifle
Last edited by DaveMc on Mon Aug 15, 2016 11:43 am, edited 2 times in total.
Tony asked a good question. When comparing different loads or settings, then its more technically sound to run the different groups concurrently (by cycling through, or "round robin" as Tony calls it). This removes some important unwanted variables such as barrel temperature and the stage of fouling.
Regarding 5 shot groups, the best use for them is in eliminating loads and settings, not selecting them, because the sample size is way too small. Looking at your groups I would probably eliminate the load used for group 3, because even if another 20 shots goes inside that 5 shot group, you would still say its on the large size. And if you fire many 5 shot groups with different settings, you will hopefully find some useful trends in the groups you don't eliminate e.g. in your case, lower powder charge trends better.
During initial testing working with small samples I try and look for trends. One small 5 shot group does not make a load BUT if the 3 leading up to it are overall progressively getting smaller and smaller and then progressively larger after that group then the trends are helping to identify the best load.
BATattack wrote:During initial testing working with small samples I try and look for trends. One small 5 shot group does not make a load BUT if the 3 leading up to it are overall progressively getting smaller and smaller and then progressively larger after that group then the trends are helping to identify the best load.
What BatAttack says, look for TRENDS.
Also, since you interested about accuracy at 200yds, dont worry about ES/SD. The Benchrest world Champions dont worry about ES/SD, dont weigh charges or anything. For them, the node (and inherant accuraccy) is what they are after.
If however you might one day become interested in accuraccy at 800-1000yds, well then things change drasticlly.
Tim N wrote:Hey Steve, The last group was 59.0 and 3 of the 4 were 2mm high and 6mm wide
Tim that ES of 28 would turn me off that 59.0 load. What ES would you get if you combined the velocities of your first five shot group at 59.0gr and the last four shot group? Could be a great load for the shorter ranges but for the longs I like to see consecutive well shaped groups with an ES in the low teens. I would have a good look between your 59.5gr and 60.0gr loads but suspect you may already have a hummer of a load already nailed down.
One more thing that has me wondering is the effect of a Magnetospeed on a barrel while doing these initial tests. Some say they make no difference to the group size or shape given the heavy barrels we use and others say they never have anything attached to the barrel when shooting test groups.
Hey Steve, The "Hummer" load is hopefully just around the corner- a bit like digging for gold. I am away this weekend but John P has generously offered(been conned into) testing at 600 for me. The trend in my initial groups was the higher velocity reduced the ES so I'm trying 60.5 of 2213 and 59.0 just for interest sake.
Graham, Add 200 f/s to those figures and I'll be a happy camper.
We don't rise to the level of our expectations, we fall to the level of our training. Archilochos 680-645 BC
! 
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