windy day and another upgrade attempt

[jhm757]

Well I got my 4 tins of 33.95gr JSB King Heavies today. Don't really understand why it takes 5 days to come from Ohio to Central New York.

They look very good, loaded up my three magazines, looking closely for damaged skirts and didn't see any, they seem even better than the first batch I got. Hopefully these will give me that 1" group at 100yds that I have been soooo close to getting but haven't achieved yet.

But anyway as predicted now that my pellets are here so are the winds.

15mph winds will not make for great groups, will have to wait for this evening and see if things calm down.

Jim - jhm757

[Airgun.Sniper]

 No those winds dont help. I shoot in at 100 yards...because the only way to be good in the wind is practice in it. Im going to try again when we get back in Ohio

[jhm757]

Well the winds died down pretty good this evening. So I went out to the 100yd range and made some more attempts at upgrading my rank.

Shot 65 shots 5 shots at a time, managed to get 4 out of 5 under an inch five times. Still couldn't get 5 in under an inch. Groups ranged from just over an inch to about 1 3/4 inches, most between 1 1/4" and
1 1/2".

Tonight I think I will tear the gun down and give it a good cleaning, polish the bore some more and polish the hammer some more, and then if the winds cooperate I will give it a try again tomorrow.

If nothing else I ought to get lucky one of theses times and get all five in under an inch I have done 4 out of 5 Sooooooo many times.

Jim - jhm757

[rsterne]

Here is an interesting little graph relating group size to the number of shots in the group.... It is from this website.... http://www.the-long-family.com/group_size_analysis.htm



That is the statistical probability of the group size for a gun shooting 1 MOA.... Note that 4 shots is the closest to the likelihood of getting a 1" group with such a rifle.... at 5 shots, the group will average about 1.15", 6 shots about 1.25", and at 10 shots about 1.5".... It doesn't mean that you won't eventually shoot a sub 1" group.... but it does explain why that 5th shot is so elusive.... and what to expect if you shoot 10 shots....

Bob

[jhm757]

That is interesting Bob!

I just did a major clean and polish, barrel and hammer, and put a little dry graphite on hammer.

Hoping I might tighten my groups just that little bit I need.

But the statistics don't lie getting that fifth one in there is tough.

Tomorrow is another day I will try again if the winds cooperate.

Jim - jhm757

[rsterne]

Basically, to shoot consistently under 1" at 100 yards, for 5 shot groups, you need a rifle (and shooter) capable of about 0.85 MOA....

Bob

[jhm757]

Basically, to shoot consistently under 1" at 100 yards, for 5 shot groups, you need a rifle (and shooter) capable of about 0.85 MOA....

Bob

I'm pretty sure I'm capable, not so sure about my .25 SynRod, but I will keep trying things to improve my groups!

My latest thought is to weigh my pellets to see how much they vary. And then shoot them in batches that weigh close to the same.

A lot of the shots that kill my 1" groups are either high or low, so I'm thinking it could be caused by varying pellet weight.

I have a friend with an RCBS digital reloading scale. I need to get over to his place and check a tin of 33.95gr JSB Kings and see how much they vary. Maybe that will explain the highs and lows.

Jim - jhm757