I bought a 100 ct box of 105’s for my father’s 6GT….satisfied with the results, I went and purchased a 500 ct box…base to ogive went from .580” to .600” consistently….seating bullets for same jump, I’ll now have .020” more bullet down in the case…how should I expect this to alter my groups? Do you expect I’ll need to start over with load development? BTW….website says base to ogive is .624”….that’s .040” off from my first box! Seems like an awful lot to me!
Too much variance in bullet specs?
- Thread starter Jody Simcox
- Start date
If you are seating the previous box touching or jamming the lands, you'll probably need to do a little load development to adjust. If you've been loading off of the lands and have room without touching the lands, I'd simply seat the new bullets so that the bullets are down in the case at the same depth as before, which will probably give you the same performance. But that too can depend on just how close those longer BTO's get you near the lands where there can be a pressure spike that increases your velocity enough to change the timing with harmonics.
Most people use the same jump to the lands.
L.Sherm
Silver $$ Contributor
I've seen very little in the same lot of 6.5 and 30 cal but different lots different story.
Variation is the spice of life, just accept that and you will be much happier.
That is unless you are a benchrest shooter, then as you lay in bed at night you think of all that variation
and you toss and turn and toss and turn. No sleep for you as you have Variphobia.
All kidding aside I shoot PRS style stuff and for me simply keeping the CBTO the same has
worked fine for me. But I must say I dont recall ever having .020 variation between lots.
That is unless you are a benchrest shooter, then as you lay in bed at night you think of all that variation
and you toss and turn and toss and turn. No sleep for you as you have Variphobia.
All kidding aside I shoot PRS style stuff and for me simply keeping the CBTO the same has
worked fine for me. But I must say I dont recall ever having .020 variation between lots.
I have been using Berger bullets in a verity of different calibers and have not had that experience.
Are you comparing the bullets before or after loading them in the case. The problem might be with your bullet seating die.
Are you comparing the bullets before or after loading them in the case. The problem might be with your bullet seating die.
I am a long range BR shooter and I sort all my bullets. Hand made custom bullets will usually go into four or five sorts. Berger's will go into 11+ sorts with an occasional bullet badly out of spec.
For hunting rifles, all I do is measure base to ogive and make sure there aren't any way out of the norm. It takes just a couple minutes to check as I am pulling out bullets to load.
For hunting rifles, all I do is measure base to ogive and make sure there aren't any way out of the norm. It takes just a couple minutes to check as I am pulling out bullets to load.
Before…bullet base to ogive….seating die never touched the bullets
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I’ve now loaded several of the newer bullets with the same .060” jump to lands and several with .040” jump to lands (in an attempt to have same amount of bullet seated into the case)….will try to shoot them soon…
Yes…identical…G1 .536…G7 .275
Only thing I measured was base to ogive….and now I’ve loaded all of the original, shorter bullets…failed to compare overall length of bullets…
You don't think the attributes of measure matters? Or you just missed it?
Just missed it…I certainly think measurements matter….that’s what started this thread…
I think BTO is the worst measure, and as demonstrated here really.
With BTO you don't know what it means, so you couldn't credibly act on it.
Has his ogive radius shifted datum? Bearing length? Base length?
Would you act on each or their summation the same?
My single measure is ogive radius, with meplats pointed.
Both meplats and nose shape affect BC.
What happens behind the ogive datum is difficult to define, and matters less anyway.
With BTO you don't know what it means, so you couldn't credibly act on it.
Has his ogive radius shifted datum? Bearing length? Base length?
Would you act on each or their summation the same?
My single measure is ogive radius, with meplats pointed.
Both meplats and nose shape affect BC.
What happens behind the ogive datum is difficult to define, and matters less anyway.
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