Bullet Base to Ogive Grouping

[wkdickinson]

I know this topic has been discussed many times and I have read most of the threads regarding it, but I haven't seen much regarding how people actually group their bullets. I just measured 200 Berger 105gr Hybrids all from the same lot, using a Hornaday comparator mounted on a Mitutoyo "Absolute" caliper. Here is what I found:



What I am looking for is a better understanding of how fine/course to group these. I am really considering just throwing them all together, since 99.5% fall within .004 and 86.5% fall within .002. Frankly, I doubt I can shoot the difference here. My discipline is primarily 600 yd. F-class.

Any thoughts would be appreciated.

 

[Bill Norris]

FOLLOWING

 

[dstoenner]

Have you done seating depth tests in your load development? If you have then how wide is your node. That then answers your question. Just my 2 cents but i would cull out the tails and shoot the middle 3 bars. Then you know you don’t have any unknowns

david

 

[mikecr]

I'll predict the half-effort endeavor dead ends with nothing repeatable.

 

[wkdickinson]

Have you done seating depth tests in your load development? If you have then how wide is your node. That then answers your question. Just my 2 cents but i would cull out the tails and shoot the middle 3 bars. Then you know you don’t have any unknowns

david

Correct me if I'm wrong, but how does BBTO effect jump? The die references off some point on the ogive and seats the bullets consistently from that point. The distance from that point to the bullet base has nothing to do with jump.

 

[wkdickinson]

"Half Effort Endeavor" - what does that mean?

 

[BartsBullets]

Size two pieces of brass. Seat the longest ogive bullet and the shortest. Then measure both cartridges with your ogive checker. Let me know what they measure after seated.

 

[ckaberna]

Load a few from each extreme, measure and shoot. See how much difference there is.

 

[jackieschmidt]

Correct me if I'm wrong, but how does BBTO effect jump? The die references off some point on the ogive and seats the bullets consistently from that point. The distance from that point to the bullet base has nothing to do with jump.

^^^^^^^^

that being said, It makes me wonder why the wide discrepancy.

Like any custom bullet maker, I can make 500 bullets, and there is absolutely no difference in any of the measurements. Or 5000 for that matter.

this leads me to believe these Bullet’s in that box did not come out of the same run.

But then, I have no idea what Berger’s bullet making protocol is.

 

[wkdickinson]

Size two pieces of brass. Seat the longest ogive bullet and the shortest. Then measure both cartridges with your ogive checker. Let me know what they measure after seated.

I was going to wait until tomorrow to do this, but couldn't:



I thought the point you were trying to make was that the longer BBTO would result in a longer OAL, maybe due to increased friction, but maybe I was mistaken. Please explain the point of the exercise?

 

[rwj]

Load a few from each extreme, measure and shoot. See how much difference there is.

I’ve done this test multiple times and can report that I can’t detect any difference...

 

[BartsBullets]

I was going to wait until tomorrow to do this, but couldn't:

View attachment 1290483

I thought the point you were trying to make was that the longer BBTO would result in a longer OAL, maybe due to increased friction, but maybe I was mistaken. Please explain the point of the exercise?

The point of the exercise is the bullets get seated by the stem on your bullet seater. It contacts the exact same dimension on the nose of each of the bullets. So even though there are variations in the base to ogive measurement among your bullets, the Bullet stem places the bullets to the same spot. Which is why measuring bullets base to ogive is a waste of time.

Bart

 

[mharp]

Not that Bart needs affirmation, but when I started making bullets I could not make two the same length. spent hours sorting BTO. Didn’t make any difference. Probably shot better than my nice, somewhat uniform bullets I make now!

 

[wkdickinson]

The point of the exercise is the bullets get seated by the stem on your bullet seater. It contacts the exact same dimension on the nose of each of the bullets. So even though there are variations in the base to ogive measurement among your bullets, the Bullet stem places the bullets to the same spot. Which is why measuring bullets base to ogive is a waste of time.

Bart

Thank you, then my reasoning is correct.

 

[BigWyoming]

My guess is you may find the egregious outlier from time to time.

At 600 yards, does it really matter?

At 1000 yards BC would be the greatest concern. Would that be measured by bullet OAL? Ogive is irrelevant at that point in the BC calculation?

Just curious. I was thinking about getting into bullet sorting, but do I really need to do another step...

 

[ckaberna]

I’ve done this test multiple times and can report that I can’t detect any difference...

Exactly, Then why sort this way?

 

[rwj]

Exactly, Then why sort this way?

I don’t anymore based on my test results…

 

[Ccrider]

Exactly, Then why sort this way?

I think that is Bart’s point. But I could be wrong.

 

[ckaberna]

I think that is Bart’s point. But I could be wrong.

I’m sorry, I got “rwj” mixed up with the OP.

 

[Bill Norris]

I realized many moons ago measuring bullet base to ogive did nothing for accuracy.