How can 1.930 and 2.005 ogive shoot the same

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Shooting loads with 24.5 Varget and 73gn .223 Bergers today. I kept the 24.5 the same, but moved the bullet out with each five shot group. Started at 1.930 and went out to 2.005 ogive which is on the lands. Both 1.930 and 2.005 shot 1/2 groups. In between the two extremes the groups opened up a bit. How can this be? Savage LRPV.

Also, can anyone point me to a good explanation of analyzing chrono data? Thanks.
 
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Just a couple of questions. Is the bullet in the lands??That is to say, does the leade in the chamber leave marks when you extract a loaded round. If the bullet is not in the lands I doubt changing seating depth will have a great impact on groups one way or the other. Secondly, how are you measuring the seating depth of the loaded round?? If you are not using some sort of an ogive checker you are not likely to learn a lot. Bullet jackets are seldon the same length over the point of the jacket. To accurately measure a seated bullet use an ogive checker such as a Sinclair "Nut" or a Hornady (used to be Stoney Point) ogive checker. Buy the checker to suit the bullet you are shooting(.22, 6mm, .30,etc.).

Mike Swartz
 
I use the Hornady guage and seat ONLY to ogive measurements never OAL. 2.005 is on the lands.
 
It would seem that you've got a solid half inch rifle. Just guessing, the "in between" seating depths will likely shoot half inch another day.

If it didn't sound so lousy, I would have suggested you find somebody to buy that chronograph before it drives you nuts.
 
You didn't mention how many groups of each setting you shot. Don't put too much stock if you only shot one group of each. As Wilbur pointed out, another day may find other depths seemed better. Now on the other hand if you fired 5 groups of each setting, randomly then your data is a little more reliable. My favorite tale is of a relative of mine that went out and fired 3 shot groups out of his Colt-Sauer .270 trying to find the load that would shoot the best. He only fired one group of each charge. One of the groups produced a nice quarter inch group. He immediately went home, loaded up over a 100 rounds just like it, and thought he had the cat's meow. He couldn't get that gun to shoot less than 1 moa anytime there after. Sometimes random coincidence gives better results than anything else. Randy J.
 
yes, I only shot one five shot group per seating. Back to the range.
 
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