Confused about long range load development discussions

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Keithjohn

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I've read and heard practiced shooters/reloaders state 100 yard groups don't mean sh## that they can have good groups at 100 that are bad at 300 and VICE VERSA
I can see how a good group at 100 could show not so good at 300

BUT---

I can't bend my head around how a bad group at 100 can be good at 300 - can anybody help explain this to me ? ?
 
Some bullets stabilize more further out (until you come back through the speed of sound for most). Tail heavy bullets are known for this, 303 Mk VII is one example.
 
I have had 1 inch groups at 100 m and at 300 m is was consistent 3/4 groups
And at distance showed half MOA
Hard to get your head around it at times but testing it at distance sometimes proves different found results then100 m testing
 
Keithjohn said:
I've read and heard practiced shooters/reloaders state 100 yard groups don't mean sh## that they can have good groups at 100 that are bad at 300 and VICE VERSA
I can see how a good group at 100 could show not so good at 300

BUT---

I can't bend my head around how a bad group at 100 can be good at 300 - can anybody help explain this to me ? ?
Click to expand...


The wobble doesn't get any worse, sort of stays in the tunnel so to speak.

Different for a bullet in a divergent path, where it goes in a direction (away from POA) and keeps going that way down range.

This may help, http://www.exteriorballistics.com/ebexplained/4th/46.cfm
 
Hi BC bullets for the caliber are known to take a few hundred meters to stabilize their centre of mass to the ballistic trajectory one expects. Furthermore, large SD and ES of the load play absolutely no role at 100 me but play significant role at distances 500 m and beyond. I test my "accuracy" loads at 300 m and use the 100 m shooting for chronograph and sighting.


Keithjohn said:
I've read and heard practiced shooters/reloaders state 100 yard groups don't mean sh## that they can have good groups at 100 that are bad at 300 and VICE VERSA
I can see how a good group at 100 could show not so good at 300

BUT---

I can't bend my head around how a bad group at 100 can be good at 300 - can anybody help explain this to me ? ?
Click to expand...
 
I test at 100, 300, 500, and 900 meters. I have had loads that shot tight groups at 100 or 300 that didn't at 500. When I went back and reviewed the groups at 300 I found indications I ignored at 300 that showed up at 500. Things like vertical trends that were tight at 300 and I thought were simply me or winds can show up at longer ranges as a trend.

I tune for about 1" groups or less at 300 because that is what I need to win in F-Class. However, groups that size don't give enough information to determine further distance performance and can hide trends if you are shooting in mirage or slight breezes.

Also, a significant number of bullets do not shoot well once you get downrange. There are distances where performance diminishes with some bullets. 500 - 600 is one and another is 800 to 900.

Same thing can happen at 100. The groups are simply too small to understand what is happening.
 
SteveB said:
I test at 100, 300, 500, and 900 meters. I have had loads that shot tight groups at 100 or 300 that didn't at 500. When I went back and reviewed the groups at 300 I found indications I ignored at 300 that showed up at 500. Things like vertical trends that were tight at 300 and I thought were simply me or winds can show up at longer ranges as a trend.

I tune for about 1" groups or less at 300 because that is what I need to win in F-Class. However, groups that size don't give enough information to determine further distance performance and can hide trends if you are shooting in mirage or slight breezes.

Also, a significant number of bullets do not shoot well once you get downrange. There are distances where performance diminishes with some bullets. 500 - 600 is one and another is 800 to 900.

Same thing can happen at 100. The groups are simply too small to understand what is happening.
Click to expand...

What he said :>)
 
for me who can't always get out to my range that often I shoot groups at 100 to find my accuracy nodes.

After that I will load long strings at above, below, and on that node to test SD/ES over the chronograph and test accuracy at long ranges at the same time.

sometimes the node is exactly the same as my accuracy node and sometimes it's not but it's usually in the area of the nodes for me.

Some people don't bother and measure SD/ES over the chronograph and completely ignore accuracy. once they find a consistent load they play with seating depth to make it accurate. I have never tried this way but I am skeptical of whether your actually achieving the best trade off of accuracy and consistency or just the best consistency.

Then there is the Scott Satterlee method. Try it if you have a chrono but I haven't heard it working for most.

If you don't have a chronograph there is other methods. mainly the OCW test comes to mind at range looking for low vertical dispersion.

my recommendation for finding a load:
- find popular recipes for the powder and bullet you plan to use double check it's safe
- load both above and below that charge increasing in .2 increments
- load the bullet at .020 off the lands and/or within mag length if you intend to use it.

and use what method works for you in your situation.
 
I have never found a load that shoots well at 100 yards that does not also shoot well at long range. (Using high BC bullets)

But I have found that my accuracy at 300 yards is often better than (in terms of MOA) of what I shot at 100 yards with more marginal accuracy loads. (Again with high BC bullets.)

I think there might be some sort of cork screw effect where the rounds are circling the centerline of flight and the base centerline is more consistent than the cork screwing around that center line. As mentioned above, eventually the bullet goes to sleep and the cork screwing settles into a nice spiral.... but that settled out path is not necessarily on the center line.

I've read about this in books and I think they refer to it as precession.
 
Yes, a rifle that shoot 1 minute at 100 might very well shot a half minute at 300 or 500.

It has to do with barrel whip and compensation.

A slower bullet is automatically shot a little higher, and comes back into the group farther down range.

This is why we shot #4s at long range for a long time after stiffer actions were available.
 
https://www.longrangehunting.com/articles/load-tuning.281/

https://www.longrangehunting.com/articles/precision-reloading-for-long-range-hunting.17/

Method I have used for a couple of decades and it continues to very well.

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New McGowen prefit for my Rem 783 in 6.5 Creedmoor, H4350, HRN 140gr BTHP or Berger 140gr VLD as marked, CCI 200, in formed PRVI 22-250 brass. 200yds on a calmish day. All ammo loaded to feed from the mag so no OAL was adjusted. Each letter is 0.2gr higher.... except for the "D +0.1gr"

work up the load using a precise scale... tune around most likely node with very small change in powder... voila. Except for 6 sighters and 2 foulers, this is all the shots fired down this new barrel - 40rds. I think my load tuning is done.

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Good barrel, good optics, good set up, properly made and accurate powder charges. The barrel will tell you all you need to know if you are looking at the target.... not the smartphone.

IMG_1990.jpg

It really should be this simple.

Jerry
 

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308BAR said:
Research positive and negative compensation. Forgive me if your head explode or implodes from the theory. Lol
Click to expand...

It was a 'theory" I found hard to accept. So I loaded ammo with my match load and then 3/4 grain lighter and heavier and shot at 1000 yards.

With a match rifle (single shot front locker) and my #4, the standard ammo all went into the bull.

With the #4, the mild and hot ammo also went into the bull.

With the match rifle the hot ammo was very high in the bull or inner ring. The mild ammo missed the target low.

At 100 yards the #4 shot a 3" vertical group, as it compensated.


EDIT: I checked my notes. The first time I ran this test I used a 3/4 grain variation, up and down. Did not see much of a difference at 1000.

So i repeated the test with a 1.5 gr variation (43.5 gr, 45 gr & 46.5gr.) The #4 put them all into the bull, the low charge with the front locker missed the paper (a 6 foot target).
 
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Physics is physics ... a bullet that is “off course” @ 100Yd does not steer back to the centerline (by any appreciable amount) with distance. The term “appreciable” refers to the cyclonic swirl effect, sometimes referred to as “augering” which (if my recall is correct) can be up to .05” in a hundred yards. If the bullet is off course by an inch at 100yds and still “wobbling” a bit ... and “stabilizes” ... thereafter.... that stability does not steer it back towards the centerline.
Anyone arguing that their particular rifle “steers” them straight needs to explain why the same does not happen with every same/twisted/velocity bullet exiting another firearm.
 
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What I have been doing recently for load development on all of my rifles was mentioned as the "Scott Saterlee" method above and I have found it works relatively well. What I do is load up the bullet and powder I want to use from book minimum to a little over book maximum (depending on the caliber) in 0.2 gr increments. I usually shoot two of three identical strings of these loads over a chronograph and into the dirt (forget accuracy for now) and graph the recorded velocities. You will very quickly see a few charge weights where the powder has gone up 0.4-0.8 grs, but the speed has only increased 20-30 ft/s! Those are generally your velocity nodes and where I then start playing with the other variables that will determine the accuracy of the load (seating depth, primer, neck tension). Keep in mind that I, unlike Jerry, am only looking for 0.5 MOA of consistent accuracy in an attempt to ring steel in a PRS/NRL match, but if you are looking for the utmost F-Class accuracy, then the other methods will probably work better :D

As for bullet stabilization, I tend to agree with JEC's comment "physics is physics" and once a bullet is out of your barrel, it is either stable or not. In my mind, the concept of a bullet being more stable at 300 yards than at 100 yards is a little outdated and probably pertained to when manufacturing consistency of lead core, copper jacketed bullets is not what it is today. From my experience, the reason people will shoot better at 200-500 yards than they do at 100 is generally due to the mental stress of observing your bullet holes easier at 100 than you do at distance, but that is my 0.78 cents.
 
I would respectfully disagree with the statement that a bullet is either stable or not as that is this is not what has been found. The design of bullets is a huge issue and at certain ranges the bullets can destabilize and this has been known for a long, long time. For example, the 168 grain Sierra Matchking was designed to win at 300 meters and it does a great job within that range parameter but it is so unstable at longer ranges that many ranges have banned them for 1000 yard competitions due to the danger to the target pullers.

The latest generation of high BC bullets are proving to be very hard to keep stable at longer ranges but now the marketplace has been conditioned to accept that only high BC bullets are the "best" thing to consider.

The idea that a bullet is accurate at all ranges has not been proven to be a fact.
 
SteveB said:
I would respectfully disagree with the statement that a bullet is either stable or not as that is this is not what has been found. The design of bullets is a huge issue and at certain ranges the bullets can destabilize and this has been known for a long, long time. For example, the 168 grain Sierra Matchking was designed to win at 300 meters and it does a great job within that range parameter but it is so unstable at longer ranges that many ranges have banned them for 1000 yard competitions due to the danger to the target pullers.

The latest generation of high BC bullets are proving to be very hard to keep stable at longer ranges but now the marketplace has been conditioned to accept that only high BC bullets are the "best" thing to consider.

The idea that a bullet is accurate at all ranges has not been proven to be a fact.
Click to expand...

That certain bullets are more/less stable transitioning from supersonic flight through transonic into subsonic is widely accepted and understood. When this occurs, it doesn't pertain to a particular range/distance more so the speed of that bullet and how well it's design deals with the aerodynamic disturbances that go along with slowing down below the speed of sound. What is being discussed here is a bullet not stabilizing till some distance further than 100 yards, really an apples and oranges comparison to what you are talking about.
 
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