Load Development Without Shooting Groups?

[TORCHRIDER]

This may be a stupid question and way over simplified, but it is something that has been bugging me, so thought I would ask.

Whenever I read instructions about shooting OCW, Ladder or other methods of group development, I keep seeing comments to the effect of...

"In most instances the best loads have the smallest Extreme Spread (ES) and Standard Deviation (SD) over the chronograph compared to other loads."

If this is the case, why do we shoot for groups? Wouldn't introducing the opportunity for user error just add confusion? Why not just shoot the loads over the Chronograph and make a decision based on the ES and SD data? Wouldn't that eliminate the user error in shooting groups?

Flame On.

 

[rcoody]

This may be a stupid question and way over simplified, but it is something that has been bugging me, so thought I would ask.

Whenever I read instructions about shooting OCW, Ladder or other methods of group development, I keep seeing comments to the effect of...

"In most instances the best loads have the smallest Extreme Spread (ES) and Standard Deviation (SD) over the chronograph compared to other loads."

If this is the case, why do we shoot for groups? Wouldn't introducing the opportunity for user error just add confusion? Why not just shoot the loads over the Chronograph and make a decision based on the ES and SD data? Wouldn't that eliminate the user error in shooting groups?

Flame On.

lot more a play here than SD's.

lots of ways to skin this cat.

for me I find you can't predict what your rifle is going to like. I find the bullet, load and seating depth for best groups before I put it on the chronograph. Sure I have a pretty good idea of velocities during load development from the charge I am using. Usually when I strap on the V3 I am pleasantly surprised

personally I think low SD's are more an example of consistent reloading practices then anything else.

 

[ohiohunter]

The guy who won the world (or national) 1k fclass w/ the gun called purple haze started his load development over a chrono. This would greatly reduce vertical vs shooting for groups at 100yds or even 200. Vertical changes may not be evident at shorter distances giving the shooter a false positive on their load.

 

[TORCHRIDER]

The guy who won the world (or national) 1k fclass w/ the gun called purple haze started his load development over a chrono. This would greatly reduce vertical vs shooting for groups at 100yds or even 200. Vertical changes may not be evident at shorter distances giving the shooter a false positive on their load.

Does this suggest that for LR accuracy, the data resulting from chronoed loads is more important / more heavily weighted than the resulting groups shot at 100 or 200?

 

[ohiohunter]

Does this suggest that for LR accuracy, the data resulting from chronoed loads is more important / more heavily weighted than the resulting groups shot at 100 or 200?

Its possible, but don't be so absolute. You can get good groups and have inconsistent velocities at 100yds... times that by 10 and you can see your vertical, but most people do not load develop at 1000yds.

There is more than one way to skin a cat.

 

[Bart B]

While low ES and SD numbers in muzzle velocity are important for accuracy, they're hard to measure precisely and repeatably. Here's what to expect testing a load for its muzzle velocity numbers different ways:

Barreled action fixed in place; doesn't move in recoil. Highest velocity and lowest ES and SD numbers. Best test of the ammo for velocity numbers. You can build a rig out of a 2x6 and other parts bolted onto it then clamp it to your bench with C clamps. Not good for accuracy but best for assessing velocity numbers. It eliminates all human variables that modify velocity numbers.

Complete rifle clamped in a free recoiling machine rest, moves quite repeatable in recoil. Much less average velocity (depends on the rest weight) but still very low SD and ES numbers.

Complete rifle hand held to the shoulder as it rests on bags on a benchtop. Lowest average velocity but much bigger ES and SD numbers. Several people shooting the same rifle and ammo will get a 50 to 100 fps spread in average muzzle velocity. ES and SD numbers will also have a wide range. Not to indicative of what the load really does. This method typically produces a 4X to 5X greater ES and SD numbers than the fixed barreled action method above.

Complete rifle hand held properly slung up in prone with a bag under its fore end and stock toe. Fairly high average muzzle velocity plus SD and ES numbers are also smallest for any hand held test method. Keep the same position for each shot moving minally between them. This method produces a 2X to 3X greater spread in ES and SD numbers than the fixed barreled action.

================

More often than not, bullets leave the barrel on its upswing so those leaving at a slower muzzle velocity depart at a higher angle that compensates for it and they'll strike point of aim. Faster ones leave at a lower angle that compensates for their less drop down range; strikes the point of aim. Which is why many loads shoot smaller groups in MOA's at longer ranges than shorter ones. Depending on where the center of mass holding the rifle is behind and off center from the bore/recoil axis, the barrel will whip different amounts in different directions while the bullet goes through it. Where it exits plays a big part in where it hits at target range. This is why no two people have the same zeros for a given rifle and ammo at any target range.

I've shot several bullets at 1000 yard targets going through a chronograph 10 feet away. Sometimes faster ones would strike below call and slower ones above call. While only an inch or two, it shows what happens when us humans don't hold the rifle exactly the same for each shot and the muzzle axis points to different places when the bullet leaves.

 

[Rich Coyle]

I did sorta of a test with an accurate .223 Savage. Out of the box plastic stock with a heavy 26" barrel. Ten shots from the bench at 200 yards with minimal contact produced .870". Same thing with me holding it like I was in the varmint field with a good rest: 2". Nothing changed but the shooting style.

 

[Mikecr]

I work on best PRECISION 1st. That's grouping. And I 'hope' my ES is adequate, given best reloading efforts I'm aware of.
If ES isn't good, I change primer/powder combinations(same seating), shooting new ladders and looking at final ES again & again.
My grouping and ladders are at 300.

Then I take my best precision and work from their for Cold Bore ACCURACY.
This I do at 200,, because for some reason this happens to be my most difficult range..
I think it's my eye glasses, but once good there I'm better to 600 at least.

 

[J E Custom]

This has been a long running debate, but it really doesn't matter as long as you get results.

I used the shoot and then chronograph method for many years and got where I wanted. Some times it took many rounds of trial and error though. So I tried reversing the process and shooting through a chronograph first to find a good consistent powder. primer and bullet weight combination. (Very low SD,s and ES,s) once I found the right combination, Then I worked on the type/brand of bullet, and seating depth for accuracy.

This has saved me many firings and is the way I work up loads now.

At normal group testing distances, the differences may be small. But when you extend the distance, A low SD/ES can make a difference. I have had good shooting/grouping at 100 or 200 yard that when pushed to 600 + yards, went bad. (Most all of these had poor SD,s)

With components being hard to come by, I find that this way I use less to find the best load and don't get on a trail of a good load only to find that at long distances it falls short of my needs.

While Chronographing If the ES is to far apart after only 2 or 3 shots I abandon that load and later pull the bullet and reload the remainder of them with another combo.

A good SD/ES Does not automatically guaranty an accurate load, but it does reduce the potential
of a bad load.

Just the way I load for accuracy (And economy)

J E CUSTOM

 

[Lefty7mmstw]

I'll often run the charge up on a bullet until the rifle seems happy and is at decent pressure/velocity. Then I'll load up enough of that load to wring the rifle out and see if she's actually grouping.
The only time I bother grouping as I run the charge up is with components and/or a rifle/chambering I haven't worked with much. If I can't get quite down to usable accuracy I'll work on seating depth ( I try to stay at mag. length to start with), but if the rifle is acting like a shotgun, I'll go to another powder or bullet. Most of the time a simple run up to pressure will produce good groups with no further work.

 

[MarkA]

I chrono to hit goal velocity first using OBT table and try to get good node using QL before I ever shoot at a target. Saves a lot of firings for me and very seldom have to change load or are not satisfied with a load.

I will use multiple sources to try and start with,or pick most accurate powder for bullet load combo.

Nosler load data
Berger load data
Barnes load data
And old Steve's pages

As been stated results are what matters not path to get there.

 

[Engineering101]

I live right by one of the best ranges on the west coast and I don't mind going there every day (except weekends). That has influenced my approach to load development. I typically pick a load in the bottom third of the velocity range and go fire maybe 6 rounds at 200 yards with 3 different loads a grain or so apart. If you do the math that means I'm firing 2-shot groups. If any 2-shot group is tight, I load 5 more of those to confirm that they do indeed group and have low ES. If I get no tight groups in the first batch, I move up in powder (assuming there is room to do so) and repeat. At some point I usually get at least one 2 shot group that is tight. Interestingly it is pretty rare that the 2-shot group is misleading so the 5 shot group is usually tight also. I tend to seat VLDs within 0.005" of the lands and others around 0.020". I don't care about mag length as the last couple of dozen animals have all been 1 shot kills (I don't shoot at running game anymore which helps.) After I get a load that will do 0.5 MOA or better I move over to the 600 yards range and verify the load will do 0.5 MOA there as well. It is unusual that it won't but it does happen. If the load works at 600 yards, I do a drop test by firing a 3-shot group at 200, 300, 400, and 500 yards all on the same piece of paper all aiming at the same spot with no scope dial up. Based on that test I figure out the BC and plug it into my ballistics program and the gun is ready to hunt.

 

[thekyrifleman]

Seems to me it's like trying to enjoy sex without gettin' laid!!! Sorry, just being a smart a**!!! Gotta shoot'em, I've seen plenty of small deviations and large groups and vice versa!!!

 

[FEENIX]

Seems to me it's like trying to enjoy sex without gettin' laid!!! Sorry, just being a smart a**!!! Gotta shoot'em, I've seen plenty of small deviations and large groups and vice versa!!!

[ame]https://youtu.be/hw3CE04LGiA?t=2[/ame]

Thanks a lot ... now I have to freaking clean my monitor.