That flier is more times than not just on the shooter but is handy to have something to blame it on. The ES would have to be on the high side to really cause some ill effects. My Rifle when shooting extemely well is in the 16 to 19 ES range and doesn't perform well down in lower range. Does not make a bit of sense but I also set the new ASSRA 100Yd. 5-5Shot Group Average Record of .3882 while in that range. While also being recorded during the endless load development outings to reach that goal with the use of the Ohler 43 Ballistic System. It's just simply where the best bullet, seating depth, powder primer combination and alloy hardness ended up at in lieu of the lower ES ranges that were recorded and just not up to the task.

frnkeore wrote on Oct 29^th, 2018 at 4:36pm:



Hey Frank, thanks for spending some time on thinking that thru As a matter of fact I have bought and downloaded the same software and worked on it simultaneously. 

I am attaching my design and wanted to discuss the differences - I see You have decided to go for shorter nose, thicker bands and shallower grooves? Also instead of one thousands tapering on the nose, You proposed to go for .002 difference.

Also I read in Paul Mathews books that the nose riding design should have a front band that would push out the fouling on the lands? 

I found my conversation with accurate from the moment I was ordering the mould and he suggested a 0.002 negative on the nose, which I agreed to - the isse is that the bore was honed in the meantime and it took 0.001 from the lands.I Thought this 0.002 was supposed to accomodate fouling. I will give it a try again with 1:20 alloy and if this does the work with no cleaning between shots. If it doesn't work, I will submit new design and order another mould fitting the barrel perfectly this time. 

BTW I see that these has been a lots of discussion on ED and SD that I find quite informative as well. I have another observation, that writing down the velocities of each shot with a point of impact and comment gives a lot more space to analyze. I agree with that statement on ES - as Harry M. Pope once said, good shooting is about the lack of poor shots. 


Happy Haloween everyone!

CF I could not agree more and your own long term practical personal experience appears to have proven it to hold true for yourself as well and thanks for sharing. 

JLouis

Whether the groups in question changed history or the world, is no interest to me. Sorry this thread took this direction.

My only attempt at a contribution is that ES/SD numbers can mean nothing or everything. It really just depends on what and how far you shoot.

For what it’s worth, in the jacketed and smokeless world, I have shot plenty of 100 yard, sub MOA groups of 15-30 rounds with multiple bullets having as much as 50 grain weight differences and over 200 fps velocity differences, using the same scope setting. ES did not mean much there.

It’s all relative because with the same rifle I’m having trouble breaking MOA at 200 yards with a 265 grain cast .308 bullet with a muzzle velocity of 900 fps. ES/SD has a meaning there.

None of it means anything to anybody but me, and all I’ve learned from it is when to throw the B/S flag at certain times.

in the past three days I have received 26 complaints about this topic .  If  you guys can't stick to  Standard deviation vs. spread on velocities,  I will delete the entire thread,  deleting  some relevant content en masse. I'm tired of the bickering as are 26 of our other member.  Stick to the topic.  Please

JLouis wrote on Nov 4^th, 2018 at 12:55pm:


JL, I think you are missing the point.  I spent many hours collecting data with my Ohler mostly testing LR BP loads.  SD was in the single digits, usually around 
5.  Wind, mirage, fouling, ect that kept my 10 shot groups at 200 yards from shrinking below a consistent 2.25 to 2.75" had nothing to do with SD or ES.

J.L.

The original question was concerning vertical spread of a load combination that included a bullet with the aerodynamics of a loaf of bread and an ES of 50. 

The original question was pretty simple, if I tighten the ES willnthe spread tighten? And included a secondary question of how do I tighten the spread?

Things got off into the weeds, at least between me and you, because in your opinion is that ES is not that important based on your experience with a pretty sophisticated gadget that measures everything but operator error of a single cartridge.

I will really start controversy and state that all bullets have exactly the same basic BC. Line as many different ones up on a table and if any of them fly off without aid, I’ll eat my words.

The potential BC, that is used to determine drop and drift and printed out for comparison purposes to buyers, is a number based on any given bullets ability to defy gravity within a tight set of conditions. If those conditions change, so does the BC. Notice it’s not the bullet changing, only the conditions it has to overcome.

With that as the base of my argument, it sounds like you are hung up on the computer telling you your BC was changing shot to shot so your ES was meaningless based on a tight group.

Because I like to argue, I say your BC was meaningless because your ES was too high.

The simple truth is that in this case both arguements are pointless. First because the distance of 100 yards was not far enough for either of those numbers to have meaning. Second because your shooting ability is not good enough for us to decide if the bullet missed the mark, or you did at that distance.

You shot a group to be proud of, no dispute from anybody there. But honestly I don’t really care about you and the group you shot. I do care what it will take to beat it. Based on the numbers you have thrown out there I see an easy way to reduce that group size 10-15%.

ES is much easier to control than the shape of a cast bullet. So cutting your ES will likely be easier than truing the base of your bullets on a lathe. But that might require a velocity change to find a better time for your bullet to exit the barrel.

I do not even know what bullet or velocity you were shooting, but your numbers give a decent idea. The bullet the OP is using might as well be a pistol bullet. ES/SD will have five times the meaning at 100 yards than the bullet you are using.

All the numbers matter, just not all at the same time and place.

Just wanted share the below all though it might not be related. These two printouts were shot one right after the other on the same day, same load, actualy the same everything and about twenty minutes apart. If you notice the BC on 1 it's was 0.413 and on 2 it was 0.402. The ES on 1 is 19 SD 5 and on 2 ES is 19 and SD 5. 200 Wind drift on 1, 7.40 and on 2, 7.25 and all data for 10 shots each  on both 1&2. Not only did the final BC calculation change for each 10 shots on each printout the BC as you can see on 1 changed for each of the ten shots. This is not prove a specific point but to only show everything is always in a constant mode of change. If I we're to dig through the pile of test results to locate the additional printouts that I shot on that day the ES could have yet been smaller than 16 and possibly the SD smaller as well and of course the BC would also be different. It would be reflected by the changes of Humidity, Temperature, BP etc. noted on the top left and being the same for 1and 2 but would not remain the same through out the day or from one day to the next. With that said you could have an ES of  7 on one day and 16 on the very next while still using the same bullet, load, primer etc. 

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JLouis