Bullet Weight Spread

[FTRinTexas]

For the Ballestic Experts: Getting ready for a 1K match. Weight sorted 5 boxes of the same lot of Berger 180 juggs on a calibrated Denver Instruments MXX-123 scale. The lightest bullet was 184.78 and the heavest weighted 185.72g. Vast majority of bullets were between 184.92 & 185.12. Question - If the velocity is 2850 fps, what would be the vertical spread between the 184.78g & the 185.72g if everything else is the same? I am trimming and pointing using the Whidden system.

 

[Chappy]

This is just me but I sort by Base to Ogive, and I don't believe bullet weight makes a difference in vertical, more of being in the middle of powder charge node and of course the shooter.

 

[RallyFan]

FTRinTexas,

Answering your question, assuming the bullets are at the same velocity, their vertical spread will be identical...

Why..? Because their flight time to target will be identical, and thus the time that they are affected by gravity will be the same - cue the 1971 Feather and Hammer Drop Experiment performed by Astronaut David Scott during the Apollo 15 mission... Both hammer and feather dropped at the same time, and they both hit the ground at the same time - it just takes longer on the Moon than on Earth as local gravitational acceleration is different because the Moon and the Earth have differing masses. Here on Earth that's 9.8m per second per second...

What actually happens (assuming identical charge weights and powder surface areas etc), is that the heavier bullets accelerate slower, and reach a lower muzzle velocity when compared to the lighter bullets. Thus the heavier, slower bullets take longer to reach the target, and thus are affected by gravity for longer, and thus are deflected further...

Hope this helps...

From your weight sorting you'll have found a classical Gaussian distribution of weights (a bell curve). I suggest that you shoot the lighter and heavier bullets as foulers, and then shoot the remaining bullets in weight order to minimise variance between rounds. While this is likely to be only a small vertical difference, every little helps, and you've already done the hard work in the sorting anyway.

Regards,

Paul

 

[XTR]

For the Ballestic Experts: Getting ready for a 1K match. Weight sorted 5 boxes of the same lot of Berger 180 juggs on a calibrated Denver Instruments MXX-123 scale. The lightest bullet was 184.78 and the heavest weighted 185.72g. Vast majority of bullets were between 184.92 & 185.12. Question - If the velocity is 2850 fps, what would be the vertical spread between the 184.78g & the 185.72g if everything else is the same? I am trimming and pointing using the Whidden system.

This is the kind of stuff I hate to see new shooters get wrapped up in.

It will not make a difference that you can see over the course of a 100 shot F class weekend.


I shot a 20 shot test string at 600 yards with my 308 this week. New WW brass, out of the bags, just ran it over a mandrel, and inside chamfered it, that's all. Bullets were Berger 200s out of the box, nothing pointed.

5 sighters to warm and foiul the squeeky barrel. When it was said and done I had 4 shots that I called out of the group on bad position when I shot them, and I clinked up one after the first shot . The remaining 15 shots the total group was .58MOA, the vertical was .316 (under 2"). If I put in the 4 "flyers" and the shot I dialed off of, the entire 20 shot string was .875 total and was a 199-11X on s 600 yard F class target.

You don't need to be worrying about fairy farts and pixie wings, load and go shoot. You let this stuff get into your head and you don't trust your loads. If you have done your basic load work and have a good rifle then if you are getting unexplained shots that nobody else is getting it isn't the equipment.



[edit] The point is to take the example above, the only point that I dropped out of the 10 ring was on me, not the equipment.

In the now locked/deleted thread about how this forum fails new loaders I considered posting an example similar the initial post. New shooters come in and read about people weighing bullets, cases, even primers, sorting bullets and brass, pointing bullet, trimming meplats, sorting by ogives, turning necks, trimming, uniforming flash holes, uniforming primer pockets, and in F-TR they start looking at loads for 215s because JBM says it will shoot inside of what ever it is you are shooting now, or try to get other bullets up to insane velocities.

Some of that stuff may even enhance the precision of your setup. Usually I see questions like the OPs from F-TR shooters, looking for a way to win points at the loading bench. The reality is that nothing you do at the bench is going to keep your bullets in the 10 ring if you miss a full value shift of 1MPH. You will save a hellofalot more points if you understand the impact of a switch from 1 o'clock to 2 o'clock, and why that's worse than 2 o'clock to 3 o'clock, and spend the time at the range to be able to see it. Learn to tell when your position is off (I still struggle with that one).

Even with out all the "extra" stuff it takes hours to do the things that are necessary to make bullets that work well, the additional hours just aren't worth what you gain, at least initially. Even in the end, a lot of that stuff BR guys do to squeeze the last .001 out of group size, but they don't have to carry 150 or so bullets for an average 2 day weekend shoot. And they certainly don't have to carry something like the 400 or so I carry to a National.

If you are consistently shooting over 190 at 1000 yards, and you are trying to get your X count up, then start trying some things, but if you are shooting in the mid 180s, then even if you get your rig shooting .1MOA vertical you're just going to shoot pretty 8s.

 

[RallyFan]

XTR,

I agree with some of what you say, but not all... I do say go shoot & get some trigger time - but I'd qualify that and say go shoot an accurate .22lr; most people will be able to get an awful lot more trigger training and wind reading done on a .22 than on a full bore, and probably learn a lot more in the process.

As for the 'extra stuff'... Well, to many people (including myself), shooting isn't just about maximising your score or beating the next guy in line, it can be a social event, or perhaps they might enjoy the 'process' of producing that ultra consistent ammunition. Each to their own I say, and I hope we all enjoy as many aspects of our sport/hobby as possible.

Regards,

Paul

 

[Dos XX]

I sort my Varget by kernel length.

I shoot the short kernels at high altitude and the long kernels at low altitude.

 

[jamesl]

I sort my Varget by kernel length.

I shoot the short kernels at high altitude and the long kernels at low altitude.

Russell you still need to step it up a notch, this is why you keep loosing. You have to sort the kernels by weight after air drying for 72hours, lenght is just not competitive.

 

[Warren Dean]

I sort my Varget by kernel length.

I shoot the short kernels at high altitude and the long kernels at low altitude.

I do the same with H-4895. Sure seems to help, especially when the moon is full. :

 

[Dos XX]

I sort my Varget by kernel length.

I shoot the short kernels at high altitude and the long kernels at low altitude.

Russell you still need to step it up a notch, this is why you keep loosing. You have to sort the kernels by weight after air drying for 72hours, lenght is just not competitive.

Yeah yeah. You young guys always think you have it figured out. I'll just stay in the dark ages with my kernel length criteria.

I'm guilty as charged by Wade. I am currently turning the necks on Palma brass so I can shoot 200s instead of 185s and gain a little less than 13% BC. Unlike Wade who is trying to improve his x count, I am trying improve my 8 count.

 

[RallyFan]

Anyone for a nice cup of tea while the powder air drys..?
;-)

 

[Dusty Stevens]

Powder is like a fine wine- it needs to breathe

 

[Steve Blair]

I find the levity in this thread disturbing. Some of us take this very seriously. The rest of you... Well, you can do whatever you want. [br]
http://forum.accurateshooter.com/index.php?topic=3741791.msg35832447#msg35832447

 

[Berger.Fan222]

For the Ballestic Experts: Getting ready for a 1K match. Weight sorted 5 boxes of the same lot of Berger 180 juggs on a calibrated Denver Instruments MXX-123 scale. The lightest bullet was 184.78 and the heavest weighted 185.72g. Vast majority of bullets were between 184.92 & 185.12. Question - If the velocity is 2850 fps, what would be the vertical spread between the 184.78g & the 185.72g if everything else is the same? I am trimming and pointing using the Whidden system.

Interesting. Berger lists their weight tolerances as +/- 0.2 grains, so it is surprising to see a variation of almost +/- 0.5 grains.

I don't think it will affect POI though. The lighter bullets will leave the barrel a little faster than the heavier ones (assuming perfectly weighed powder charges).

But the heavier bullets will retain their velocity a bit better over 1000 yards.

Both effects are very small (smaller than many other effects) to begin with, but they will tend to cancel each other out.

If there is any real advantage to weight sorting, I think it is because weight consistency is an effective proxy for consistency in some dimensional parameter that is more important.

 

[Medic505]

I sort my Varget by kernel length.

I shoot the short kernels at high altitude and the long kernels at low altitude.

This only works if you stack the kernels longitudinally in the case. Better ignition if powder is ignited from the ends.

 

[Warren Dean]

I find the levity in this thread disturbing. Some of us take this very seriously. The rest of you... Well, you can do whatever you want. [br]
http://forum.accurateshooter.com/index.php?topic=3741791.msg35832447#msg35832447

 

[Scott Harris]

I find the levity in this thread disturbing. Some of us take this very seriously. The rest of you... Well, you can do whatever you want. [br]
http://forum.accurateshooter.com/index.php?topic=3741791.msg35832447#msg35832447

LOL, know a few folks I"m gonna forward this too!

 

[Joe Salt]

I quit weighing bullets years ago when I found a bullet that was a 1.5 grain heavy. So I done a test a 1000 yard match, during the sighter period. Ones I was in the ten ring I shot that bullet and it went in the same place, the cured me of weighing bullets. If you want to make yourself nuts the fat and skinny bullets are what you should be looking for. Don't mix them like I did.
Talk about cutting kernels, the new scale I got makes that a breeze the sartorius Entris 124-1s ;D

Joe Salt

 

[Catgunguy]

I also weigh the bullets if they are match, [I have found it does not matter if they are cheap plinking bullets]. I have also checked the bearing surface length. The last lot I have vary by .007 , the base to ogive varied by .006. and the diameter by .0005. Even with the variation not considered ,[ I shot them irregardless of the measurements] they shoot in the 2's and 3's. So some of the sorting is not necessary for most situations.

 

[BOBC]

Do whatever you think to improve your scores. If you feel it works, go for it. I guess we all could use a little MOJOE now and then.

Many X's for all.

 

[RallyFan]

I thought I'd share the results of the first batch if weight sorting I did...

All weights in grains.
Scale used is an FX-120i
Calibration weight: 50g F1 Class (UKAS)
Bullet is Berger 26409 140grain BTLR.

137.40 x 1
...
139.78 x 1
139.80 x 0
138.82 x 0
139.84 x 0
139.86 x 3
139.92 x 4
139.94 x 9
139.96 x 11
139.98 x 32
140.00 x 31
140.02 x 36
140.04 x 44
140.06 x 36
140.08 x 32
140.10 x 50
140.12 x 35
140.14 x 42
140.16 x 26
140.18 x 16
140.20 x 20
140.22 x 21
140.24 x 0
140.26 x 3
149.28 x 4
140.30 x 0
140.32 x 1