How many rounds does it take to work up a decent load?


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mugsie
September 21, 2009, 10:12 AM
Here's my typical scenario. First I go out and purchase 100 bullets, let's say 150g remington in .308. Then I see a sale, so I go and purchase 165g in Privi (don't sak why not the 168 - stupidity I guess). So now I have a couple hundred bullets. I start loading the 150s with 43g of Varget, 4 bullets. then another 4 with 44g's, 4 at 45 and 4 at 46. 47 takes too much compression so I let that one go. I did the same with the 165's also, starting at 42 and working up to 46 (20 bullets total on this one as opposed to 16 on the 150g scenario). Even if I had only one weight bullet, it would still take at least 16 rounds. That would get me in the ball park, then I'll start loading .5 grains to either side till I find what the gun likes. So now we're talking the original 16, plus another 8 to 12 more to find the right load for smallest groups.

This is typical with most all my guns. If I'm not happy with the results, I start the same scenario all over again but with a different powder. When it's all said and done, I've usually shot up 50 or more bullets and gone through a couple of different powders. Does this sound about right? Am I on the same path as everyone else or does someone have another method which works better and uses less components?

Thanks all.....

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flipajig
September 21, 2009, 11:30 AM
IMO your on the right path but i work up in 1/2 grn incrments after i choose a bullet
and a starting pdr. and instead of 4 rds I load 3 and when i shoot them i compair my tgts
and find one or two that will stand out. load 3 more ot them and run them through a crono
your most accurat load will have the smallest deveation in valosity. And when i do that i load 5 and shoot for the best groop. To save on ammo you can run the first batch through the crono. and then you have elimanated one step..

Canuck-IL
September 21, 2009, 12:42 PM
Audette 'ladder' method is widely discussed around the web. This guy has a few thoughts as well...
http://optimalchargeweight.embarqspace.com/#/ocw-instructions/4529817134
/Bryan

ArmedBear
September 21, 2009, 12:42 PM
As a rule of thumb, start where the powder just fills the case under the bullet, then go up by .5 grain increments to about .5 below the book max. Maybe load up to book max.

Somewhere in there, most likely, you'll find your accurate load.

HOWEVER... Bullet seating depth matters a lot with some guns.

jfdavis58
September 21, 2009, 01:30 PM
I've been reloading for a long time, there are no short answers to your question. I could say something esoteric like "it takes what it takes" but all that would prove is I can pi$$ you off.

Here's my first tip: stay on the page of a good reloading manual. They typically give a range or max and some increment to deduct for a starting load. In general this range of weights is in a well behaved region of the powders capabilities and everything should be good (all should cycle the gun and deliver the nominal accuracy specs).

I bought a chronograph early in my reloading and use it extensively, but others swear buy visual inspection for pressure issues and actual groups on target. Here's where it gets 'dicey'. You must know what the gun is actually capable of shooting (or what claim of capability) from the maker. Most OTC stock rifles are 1 to 1/5 MOA, Most OTC stock defensive handguns are 3 inches at 25 yards, but there are variations. Key, of course, is that you can actually shoot to these levels, you have the proper support and a measured distance that is level.

I can and I have the necessary tools. As a preliminary 'cut' I take the top powder weight, subtract the lower powder weight and divide by 4; this gives me five weights to try. I load ten of each weight and head to the range. I chronograph five rounds and shoot five rounds for a group. I look for a small spread, a small standard deviation and a tight group; often I get two out of three, on occasion I've gotten two sets where all three parameters are good (good is relative--better than the other rounds at other weights is more correct).

I then load the best performers and check +-1/2 of whatever increment I got in the previous math--3 weights, fifteen rounds each. Three go over the chronograph again, 10 go into two groups of 5 at either 25 yards or 100 yards. Two are for alibi's, if all the holes are nice and round otherwise a stability check must be performed against a large poster board target at intermediate distances and beyond the stated standard distances.

Handgun ammo must function in the gun, if it's for SD, practice or games it usually must meet a power factor, it should shoot 4-10 rounds into 3 inches at 25 yards at will from a rest and it should be stable at 50 yards (doesn't tumble and show key holes). Rifle ammo must cycle reliable and easily for hunting, self defense and plinking, it must be predictably accurate at range and it too, must be stable beyond the maximum anticipated range. In some calibers there is a danger of premature bullet fragmentation-light construction high spin---you know as soon as you fire.



I buy at least 300 rounds of anything new, more typically I acquire 500-10000 rounds (all components) for established loads.




TO be all inclusive I see you are referred to both Dan Newberry's Optimal Charge Weight Method and the Audette's Ladder method. It takes a great deal of courage to put ones personal work up for public inspection and review and that is to be admired.

It's important that we see things for what they are-and that's a safety issue that must take precedent. Newberry's OCW is just a fancy way to 'hopefully' reduce two common data collections errors: systemic error-increased powder weight SHOULD increase velocity and operator error-one tester with one metric is insufficient for statistical completeness. And all the instructions, commentary and innuendo are smoke to cover the fact he is a cheap bastard and doesn't have the funds or the will to spend the funds to produce exceptional ammo and he likes 'dissing' those that do.

Audette's Ladder is specifically for well constructed and highly 'tuned' match rifles at 200+ yards. While it's grounded in sound science, it's pure hell on the 'pair' that undertakes conducting the test. Or you will spend a bunch of money getting the best optics you can find. Two key points: the gun must be capable of sub MOA grouping (think bullet diameter plus a few thousandths) and the shooter must be able to perform to the same level----that might be 3-4% of the shooting population.

mugsie
September 21, 2009, 02:26 PM
JFdavis58 - thanks for a comprehensive breakdown. I guess I was doing it right all along. I usually go through 50+ rounds before I find something my gun likes, and sometimes I go through a few powder types. For instance, on my 223's, I went through 3 different powders, three types and weights of bullets, and over a hundred trials and errors (what do I do with the excess powder and bullets that didn't make the cut? I shoot it out anyway!). Doing all this, my 223 bold will shoot 4 rounds in a clover leaf or so at 100 yards, benched of course (I wish I were that good!). Just wanted to know if I was doing it the hard way (which I'm very good at doing too much work) or was I on the right track.

Thanks again everyone.....

Vern Humphrey
September 21, 2009, 02:32 PM
I use the ladder method. I start with a bullet with a good reputation for accuracy and the power that gives maximum velocity in the case (which is usually the best-balanced powder for that case.)

Starting with the recommended starting load, I load 10 rounds, with increasing charge weights to the maximum recommended load. Then I fire all 10 rounds carefully and keep track of the round number. Since my range is on my own property, I can fire one round, walk down and number the bullet hole, and walk back - while the rifle cools.

You will usually find that one sequence of rounds produces a tight cluster -- choose the charge weight in the middle of this cluster. If you don't get the accuracy you want, load 10 more, with the chosen charge, but varying the seating depth and repeat.

wally
September 21, 2009, 02:52 PM
An absolute minimum of 10 rounds per variable if your are working up based on accuracy (group size).

For plinking ammo, I start with the reloading manual minimum and make enough to function test all the guns I'd plan to use them in. I stop and standardize on the lowest charge weight that gives reliable function in all the guns I plan to use the load for.

Different goals, require different methods.

--wally.

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