Understanding Max vs Accurate Load

[ExAgoradzo]

Noob alert!

Why is it that the max load doesn't give an accurate load (necessarily)?

Is there a rule of thumb (i.e. so many % below max) that helps a load be more accurate?

I understand accuracy is relative to my rifle (not necessarily why...); but while I'm working up a load (say 46gr min to 52gr max of a specific powder) should I try 1/2 grain steps, whole grains? Is loading 5 rounds in with a specific powder load enough to test for accuracy? 10 rounds?

All of that is very general: specifically I'm working with 270 Win out of a BAR. I have 130gr Sierra, 90 grain Sierra, and the 130gr Hornady GMX. I have worked with my friend loading 45LC and 44mags, on two different occasions but that is the entirety of my time other than reading here and I just bought the Lyman and Hornady books last night off Amazon. Walt is going to help me with these. (I also bought 270 and 223 dies..he has everything else I need.)

Thanks again,
Greg

 

[mdi]

http://huntandshoot.com.au/articles/handload-developement-the-ladder-test/
This is one method for testing/working up a load. I normally load a few each in 1/2 gr increments, and take the best groups to repeat and mebbe vary by .2 grain loads. But I like shooting and I got nuttin' but time. I always start at or very near the listed starting loads and have never found the max. to be the most accurate, but I shoot 95%+ lead bullets. Not sure but barrel harmonics, bullet's preformance under varing presures, pressure "curve", etc will prolly play a big part in accurately spitting the bullet out the muzzle at precisely the same speed/barrel vibration?

 

[RandyP]

To the specific question, the 'max' is simply the tested and verified threshhold that will not exceed the safe limits of pressure for a specific combination of components. It was never meant to concern itself with 'accuracy'.

Never exceed the max and you should be making 'safe' ammo, all things being equal.

I load mostly plinking ammo in the low-mid range which I find to be accurate enough for my needs.

 

[rfwobbly]

Greg -
Don't load 270, but maybe I can help with the general ideas.

► Max load is not about the bullet, it's solely about the allowable chamber pressure the standards say a gun (rifle or handgun) can withstand. One way to understand the relationship is to say that your car could possibly be driven at 100 MPH. But would you be able to do your best driving at that speed? Highest and best are usually 2 different things.

► I'm not aware of any "rule of thumb" for finding accuracy. There are simply too many variables involved. That's why your reloading manuals always suggest beginning at the "starting load" and working up in incremental steps. I usually divide the allowable load range into 6-8 equal increments, and load 5-8 cartridges at each increment. Then test them all on the same day from the bench. (This includes handguns.) The results will most probably apply only to that bullet in that barrel with that powder.

► The most important step in all this is rarely discussed, but needs to be done if you expect any long-term success. That last step is to write down the results in a notebook completely set aside for just this one purpose. Believe me, if you don't the load you worked so hard to find will be a forgotten memory in 6 months.

Hope this helps!

 

[918v]

Firearm accuracy depends on three factors: firearm quality, component quality, and voodoo.

You can have the finest in firearm parts and the finest in ammunition components lovingly assembled by the finest gunsmiths and handloaders, but that don't mean it will put five shots into an inch at 100 yards.

There are certain powder/primer/bullet/OAL/case/barrel length combinations that shoot teeny weeny groups. There is no explanation for this other than voodoo. Such combinations have ideal combustion properties that allow a firearm shoot it's best. These properties just cannot be easily replicated by substituting components. You have to research and test your own loads. That's the fun part.

Also, consider weather. I have never shot decent groups on a hot and humid day. I think the ideal weather for load testing is warm, calm winds, with less than 35% humidity. I got no proof for this, just my observation so you Internet warriors just stay calm. Hold your attack. Save your strength.

 

[beatledog7]

Sometimes I wish there were universal %-of-max rules for best accuracy. Think of all the money we'd save on components and all the time prepping brass. Think how wonderful it would be to simply apply the "Einstein-Browning formula" to each caliber and drive nails from the other side of the county!

But where's the fun, where's the challenge, in that?

Working up loads, trying different things, is a heck of a lot of fun, and it's a big part of why many of us reload. It's why even when we hit on tack-driving micro-MOA loads that shoot laser flat to a million yards with no recoil and are unaffected by wind, we still aren't satisfied. Experimentation is how you know what your rifle likes best, and there will always be some combination you haven't tried.

The most prevalent factor in rifle accuracy, assuming the load is ok and the rifle itself is put together right and undamaged, is and always be -- the shooter.

We can control a lot of variables when we reload, but we have the most trouble controlling our human shortcomings.

 

[MachIVshooter]

Highest and best are usually 2 different things.

Blasphemy!

 

[BYJO4]

Max load is shown simply to keep you within safe pressure limits. The most accurate load for any given powder/bullet combo is going to be somewhere between start and max. I usually begin at the start point and work up .2 gr at a time.

 

[Walkalong]

As you work up a load in a rifle you will get to and pass one, two, or three sweet spots, depending on how low you start and how high you go etc. These sweet spots are where it shoots best.

The max is a pressure max. While it can happen, it is unlikely to be one of the sweet spots.

 

[gshipps]

I know people say you will find spots through out the whole range. But so far in my limited experience, I've only found the one near the top. I'm gonna try harder this fall but so far... No luck.

 

[788Ham]

I've got a Sierra 5th Edition reloading book, in it, they list the "accurate load", and then the "hunting load." for each caliber. You might get one of these and look at it, might save you several lbs. of powder and primers, just a suggestion !

 

[ExAgoradzo]

Thanks guys for the responses!
I checked out the ladder link: and I appreciate the note about the pencil and paper being important!
What I really appreciate is you guys encouraging me...I am absolutely brand new at this and over the last couple of years have learned a lot about guns, and now hopefully about reloading.
I'll check out the Sierra #5...
Greg

 

[ljnowell]

I have had some handgun loads that just got more and more accurate as the charge weight went up. At max they were great, and these loads in most cases inspired me to push the envelope and go over max, using a chronograph. Most of those found the best accuracy at max or a little under. The majority of my loads, however, always find best accuracy towards the top of the data, but not max.

 

[Naterater]

someone compared it to driving, and I can add to that... in the terms of sweet-spots or nodes in your barrel.

Let's just say that your tires are unbalanced and you are drive on a vibrating road (that goes up and down). The road would simulate the barrel of your gun and the car would simulate the bullet.
-At certain speeds, you'll be shaken the hell out of from your car and the moving road. (poor accuracy)
-At certain speeds, you'll synchronize your vibrations with the road and travel perfectly smoothly (excellent accuracy)
-There is more than one speed which will cause you to go smoothly (there are multiple nodes in a barrel)

Keep in mind, every car (bullet) is different; therefore you need to find the correct speed for every load. Occasionally the most accurate is near the max load. If it's not, there's no need to go to the max load unless you're concerned about going subsonic over a long distance or you need a lot of energy for taking down big game.

 

[Gtimothy]

The biggest problem you're likely to run into is the ammount of data available for loading a particular bullet! It can be confusing when one manual gives a particular load as being MAX then another manual has a different charge weight as being max for the same bullet.

I work my loads up from 10% below MAX in .5 gr increments loading 10 rounds each. After I shoot them, I record their performance and then load in .2gr increments above and below the best group.

This is MY method. Others may have a different approach but this works for me!

 

[Snag]

I've got a Sierra 5th Edition reloading book, in it, they list the "accurate load", and then the "hunting load." for each caliber.

Notice the specified hunting load is usually at max? Thought that was interesting.

 

[918v]

I've got a Sierra 5th Edition reloading book, in it, they list the "accurate load", and then the "hunting load." for each caliber. You might get one of these and look at it, might save you several lbs. of powder and primers, just a suggestion !

When looking at this consider the firearm. What's accurate in Sierra's Hipoint won't necessarily be accurate in your Sig, for example.

 

[helotaxi]

From the front of the Sierra 5th ed. manual:

"How did you establish your accuracy load?
These are loads that have a proven history of working well in many rifles. They generally provide a high level of accuracy in many different barrels, not just our test barrel."