Some basic reflexions about rifle precision reloading

MozPhoq

MozPhoq

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I've been reloading cartridges for pistols and semi rifles for over 12 years now. Really in all that time I have never really worked loads extensively for precision. For example I would work up loads downwards for low recoil IPSC shooting, or upward for good magnum fireworks at the range, or else to obtain 3200fps on an AR, etc. but never loads for precision.

I have trouble with the idea of trying every possibilities by the tenth of grain for every single bullet type/weight i intend to shoot. To me it barely makes sense. Not only that but what about the compounding of human errors when you shoot? To you rifle old timers out there: How exactly do you determine that your rifle has hit a "sweet spot"? All comments will be appreciated.

Thanks.
 
if my shots arent touching, then its not in the sweet spot.

I cant believe that in 12yrs you havent tried to make accurate ammunition.
 
Well, it would be WAY too much to start listing here.

Youtube actually is starting to gather a few decent videos and you can go through the reloading thread here, reloading manuals, accurate shooter website, 24hr camp fire website site.

Once you get a grasp of it and get into more specifics then post specific questions here and we will answer exactly as your situation needs.

It would be pages and pages for any one of us to start posting it here.

One thing to research as a start would be barrel harmonics, that is essentially what you are chasing down and trying to find.From there it gets interesting.

There are at minimum a dozen factors or so that play into this game just from the ammo perspective, maybe even more key points.

My brain is hurting just thinking about it.:(

Some things in a nut shell are...

-Primer selection
-Powder selection
-Bullet selection
-Brass selection
-Load testing

Then you get into more detailed information in sub sections like...

-Brass preparation, many steps
-Powder selection based on burn rates and desired results
-Bullet design and usage - many different style and dynamics

We still have to talk about rifle and environmental factors.

It is a pandoras box once you start and if you want to achieve premium results
 
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When it all comes together in muzzle velocity, spread, deviation and smallest group of holes in target with no pressure signs.

I like the highest velocity with the most consistent grouping at the yardage I plan on using them at.
 
MozPhoq said:
I've been reloading cartridges for pistols and semi rifles for over 12 years now. Really in all that time I have never really worked loads extensively for precision. For example I would work up loads downwards for low recoil IPSC shooting, or upward for good magnum fireworks at the range, or else to obtain 3200fps on an AR, etc. but never loads for precision.

I have trouble with the idea of trying every possibilities by the tenth of grain for every single bullet type/weight i intend to shoot. To me it barely makes sense. Not only that but what about the compounding of human errors when you shoot? To you rifle old timers out there: How exactly do you determine that your rifle has hit a "sweet spot"? All comments will be appreciated.
Click to expand...

Doing the Audette Ladder Test is way simpler than it seems, and it is frequently misunderstood. All you are doing is finding a spot when the barrel is on an upward movement when the bullet exits. Fast bullets exit sooner when the barrel is pointed lower, and slow bullets exit later when the barrel is pointed higher. To find it you just shoot a number of bullets with stepped velocity and match every bullet hole to the velocity measured. Then you plot vertical elevation only vs velocity. You should get a graph like this:

LadderVel.jpg


You are looking for a velocity range where velocity is increasing but vertical elevation is not increasing, or perhaps even dipping a little. That is called the sweet spot. It is tolerant to small velocity changes with no or minimal impact on POI elevation. In the graph above of three different bullets the sweet spot is the same at about 3400-3420 fps. The true sweet spot is bullet weight and other components independent. It is purely dependent on your barrel and the velocity.

The next step after you identify the sweet spot is to vary seating depth, primer used, powder used, etc to minimize velocity extreme spread and standard deviation. Not too difficult if you are organized about it.
 
For starters, Just load up a standard load, right out of a manual, or Hodgdon's on line.
Presuming your rifle is roughly sighted in, put up a target at 100 yards, with a good aiming mark.
Get the best bench rest you can get and fire five rounds, one after the other, so the barrel will get hot.
If it is a group you are happy with, great, but most likely the group will be either too large to suit you, or commonly, the holes strung out, or walked. If the latter is the case, take the rifle home and attend to bedding it. With the action fitting perfectly, experiment with the barrel, first trying free floating, but if it is a normal sporting barrel it almost surely will shoot better with pressure under the barrel at the front of the stock. It should take about six pounds to move the barrel from the lump giving it pressure.
Now try your groups. But remember, there are three main reasons for enlarged groups, shown in order of importance.
1) The shooter.
2) the rifle, including scope and mounts.
3) the ammunition.
Now, how to load for best accuracy? Using your favourite components, including the slowest burning powder that will give top performance with a lightly compressed case full of powder. Keep loading up a grain at a time, until signs of excess pressure are observed. Drop back a grain or so, and presto, you have the best load for that rifle!
 
How much neck tension....
Primers pockets....
Flash holes....
Chasing the lands on a shot out 243AI...
OCW and Ladder tests at 600y....
Projectile uniformness.....
Runout.....


These are just a few of the items that come to mind that have caused me the most grief loading for "precision"....
 
Thanks skypilot and Ron AKA, you understood precisely the meaning of my question. My question wasn't technical in the reloading sense, I know the variables that come with powder, bullets, seating depts, primers, concentricity, neck size et al. What I meant is : what do you guys exactly chase for. And Ron you gave me some really interesting stuff here. Thanks.
 
MozPhoq said:
Thanks skypilot and Ron AKA, you understood precisely the meaning of my question. My question wasn't technical in the reloading sense, I know the variables that come with powder, bullets, seating depts, primers, concentricity, neck size et al. What I meant is : what do you guys exactly chase for. And Ron you gave me some really interesting stuff here. Thanks.
Click to expand...

The highest velocity accuracy node.
 
Got you guys. I'm looking for a sweet spot that is at the highest velocity possible I guess for ballistic vs distance purpose right?

Then I will test with variables like powders, primers and seating depths always looking for the sweet spot speeds but checking for small extreme spreads and low standard deviation. Did I understand everything right?
 
MozPhoq said:
Got you guys. I'm looking for a sweet spot that is at the highest velocity possible I guess for ballistic vs distance purpose right?

Then I will test with variables like powders, primers and seating depths always looking for the sweet spot speeds but checking for small extreme spreads and low standard deviation. Did I understand everything right?
Click to expand...

Sometimes magazine length is close to the right sweet spot for OAL if not, you surely know which way to go. Lol
You have got it figured out. Fast means less error for you in drop and wind call at longer distance.
 
MozPhoq said:
Got you guys. I'm looking for a sweet spot that is at the highest velocity possible I guess for ballistic vs distance purpose right?
Click to expand...

Kind of yes. In my case for a 68 grain bullet the sweet spot turned out to be around 3400 fps. I can go a fair bit higher but I never found another flat spot. If I go to a 80 grain bullet, I can't reach 3400, so I need to look for a lower speed sweet spot. I shot a box of 80 grain, and it was not quite as accurate. I think the best sweet spot I found for it was at about 3200 fps. So it depends on what bullet you want to shoot, but yes for that specific bullet a higher sweet spot is typically better than a lower speed one.
 
That heavier bullet may carry more speed than a lighter one past a certain distance.

Ron AKA said:
Kind of yes. In my case for a 68 grain bullet the sweet spot turned out to be around 3400 fps. I can go a fair bit higher but I never found another flat spot. If I go to a 80 grain bullet, I can't reach 3400, so I need to look for a lower speed sweet spot. I shot a box of 80 grain, and it was not quite as accurate. I think the best sweet spot I found for it was at about 3200 fps. So it depends on what bullet you want to shoot, but yes for that specific bullet a higher sweet spot is typically better than a lower speed one.
Click to expand...
 
Ron AKA said:
LadderVel.jpg


You are looking for a velocity range where velocity is increasing but vertical elevation is not increasing, or perhaps even dipping a little. That is called the sweet spot. It is tolerant to small velocity changes with no or minimal impact on POI elevation. In the graph above of three different bullets the sweet spot is the same at about 3400-3420 fps. The true sweet spot is bullet weight and other components independent. It is purely dependent on your barrel and the velocity.

The next step after you identify the sweet spot is to vary seating depth, primer used, powder used, etc to minimize velocity extreme spread and standard deviation. Not too difficult if you are organized about it.
Click to expand...


Ron AKA, pardon any of my ignorance or what may seem obvious to everyone else regarding analysis of this graph but for clarity...
- the horizontal flat spots in the curves identify the optimum velocity for that rifle? (when graphing velocity vs. vertical)
- the optimum or sweet "velocity" is what is aimed for when swapping components there after (independent of component combination)


Of note,
- sophomore reloader
- using OCW method and Mystic's methods to find nodes for both my son's 7mm-08 rifle and have been very successful for my sons rifle. However my marksmanship seems to be dependent on how much java or time I have at the range for testing and is a little bit more "inconclusive" so to speak.:mad:
- I don't have a chronograph and just plotting powder charge vs. vertical on this end but a magnetospeed is in the future. I am trying to discern a correlation, in my mind, of relationships between graphs


Regards
Ron
 
Not sure of your intended use of the "precision" rounds, but chasing highest velocity may not be consistent with precision. Certainly F-Class shooters need velocity to limit time-in-flight whilst bucking winds, and to some extent, to reduce bullet drop, but over lesser ranges, there is little to choose from between a couple hundred feet per second, except more recoil, which reduces the ability of the marksman. As well as decreasing case life, increasing throat erosion, fouling, and annoyance of your neighbors on the line.
 
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Try this for a graph.

Increase powder charge in small increments. Watch the group size and orientation change... when you find the two higher nodes where groups are smallest with the least amount of vertical dispersion, use the 2nd highest and that is pretty much it.

Jerry
 
jerry,
im just starting to understand this ladder testing. So if I read this correctly, according to your data; I would choose to load my rounds at 39gr ( if this graph was a representation of what my rifle did)?
 
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