Start at the minimum load and work up...

[SimpleSimon]

If you're working up a new load, hoping to achieve the fastest velocity that remains accurate and safe for your rifle, by what increments are you increasing your powder charge? For example, I'm looking at load data with a 5.2gr spread min-max. Common sense tells me bigger jumps lower down and smaller as you approach the top end, but what's normal/acceptable practice?

 

[Craigsaun]

Good morning, I tend to go in .5 increments, then when I am relatively happy I may go .2 to get what I need. When I have what I need I may also play with over all length after I have my powder weight . I may add , I am no expert and someone may come along shortly and correct me

 

[Smellydog]

I usually start at max listed load and go either way 1/2 a GN till happy.

 

[Lateral]

It depends on the cartridge. If it's a .223, or similar, under 30gn, I'd start with .5gn at the lower end, and change to .2gn once it's closer. .5gn for 40-60gn, and 1gn for cartridges over that.

You can waste a lot of time and powder faffing about with tiny increments, with cartridges using 80gn +.

But, spend some time checking the various bullet, & powder manufacturers reloading data, so you start at a sensible point.

 

[Dalua]

I would tend to use an increment based on the overall charge, and getting smaller approaching the top, or (omnce you've found one) around a 'charge of interest'.
So perhaps 0.3gr for .222/.223-size loads, dropping to 0.2gr near the top or for 'fine work' around an apparent good load: and 0.5gr dropping to 0.3 for .270-size charges.

I do tend to start at minimum loads - certainly with an unfamilliar rifle/bullet combo. I might start a bit above minimum if I've got enough data on how a barrel behaves to be confident of doing so safely - but on the whole an extra load or two for the sake of safety seems a sound investment.

 

[dropmdead]

Assuming it's a popular short action cartridge but an unknown components, you can find a max powder load with 0.5gr increment.
If a standard long you can go a whole grain or more.

The idea is you work towards signs of pressure.
Once found for your rifle, use the maximum minus one grain (given that this is for a sporting rifle and field use).

 

[Will the chippy]

I tend to start at max then load in .3 grain back for 5 loads.
I'll shoot them lowest first. I'll shoot no more than 25 rounds.

 

[Dalua]

My question to those who actually start at 'max' is, "How you know what 'max' is for a given barrel, powder, bullet etc. combination unless you've actually worked up to it?"

If what's meant is that you start at 'book max', then I'd courteously suggest that you might be riskily overlooking the fact that the actual max for your gear and load might be well below 'book max'?

 

[muddy42]

My question to those who actually start at 'max' is, "How you know what 'max' is for a given barrel, powder, bullet etc. combination unless you've actually worked up to it?"

If what's meant is that you start at 'book max', then I'd courteously suggest that you might be riskily overlooking the fact that the actual max for your gear and load might be well below 'book max'?

Hang on a second. What you call the 'book max' will either come from a reloading manual or an app (for example the vihtavuori app is good). Both of these specify the exact bullet, powder type and will normally state what barrel length was used in the test. I sometimes take a view on different bullets, if the weight and shape is the same. But powders vary hugely - fast/slow etc, so never substitute one for another. This could be extremely dangerous.

Finally the 'book max' should still be conservative, to avoid liability, well below the max pressure for most setups. That said, the manuals say to work up from the min, so do otherwise at your own risk.

Personally I find I just reach a point of 'acceptable accuracy' somewhere near but below the max and then say its good enough for me. You can waste a lot of ammo faffing around with small increments at the limit. I want a reliable stalking round that I can replicate and rely on not to produce stuck cases or risk barrel/chamber damage.

 

[User00056]

I absolutely detest load development, so I tend to start with a mid-range charge, and load a few at half-grain increments. If, along the way, I find a load that'll shoot an inch at 100 yards I just stop there. All of my rifles are for stalking though, and a 300 yard shot would be almost unheard of for me, so I'm happy with how I do things. And I don't chase velocity either.

So I've probably been of no help whatsoever

 

[Dalua]

Hang on a second. What you call the 'book max' will either come from a reloading manual or an app (for example the vihtavuori app is good). Both of these specify the exact bullet, powder type and will normally state what barrel length was used in the test. I sometimes take a view on different bullets, if the weight and shape is the same. But powders vary hugely - fast/slow etc, so never substitute one for another. This could be extremely dangerous.

Finally the 'book max' should still be conservative, to avoid liability, well below the max pressure for most setups. That said, the manuals say to work up from the min, so do otherwise at your own risk.

Personally I find I just reach a point of 'acceptable accuracy' somewhere near but below the max and then say its good enough for me. You can waste a lot of ammo faffing around with small increments at the limit. I want a reliable stalking round that I can replicate and rely on not to produce stuck cases or risk barrel/chamber damage.

I can't quite decide whether your suggesting that you think, contrary to my position, starting at 'book max' is a good idea?
If you're not suggesting that, I'm not sure why you're asking me to hang on on a second!

 

[Bowland blades]

depends on the powder ! Only a fool would guess , check the minim and maximum and work it through on the range - stop if you get pressure signs ( iif you dont understand this seek advice face to face with someone who does ) . Pressure in one gun is not generally going to be the same in the next , so many things in play you see?

 

[HonestJohn]

I’ve always found the best load to be around 96% of max. So I’ll go down a couple of 0.5g loads and up a couple from there. And usually I’d have each of the 4 loads in two different seating depths.

 

[Miki]

Are you using an internal balistics program ?
This will give you a clearer idea of what is happening as you can define case capacity and seating depth etc
Changes of these two parameters does and can have quite a dramatic effect of the max pressure.

 

[SimpleSimon]

Are you using an internal balistics program ?
This will give you a clearer idea of what is happening as you can define case capacity and seating depth etc
Changes of these two parameters does and can have quite a dramatic effect of the max pressure.

No, I'm using the powder manufacer's (Ramshot) published data for the powder and projectile I want to use.

 

[Miki]

No, I'm using the powder manufacer's (Ramshot) published data for the powder and projectile I want to use.

Then you are partially blind as the manufacture is making 'assumptions' using CIP or SAAMI data.

Have a look here ...

QuickLOAD Ballistic Software | QuickLOAD Database for PC

QuickLOAD Software for Windows PC ✔ Ballistic Quickload reloading software → Version 3.9 requires Windows XP or newer OS ✔ ballistic Software and Ballistic calculator.

quickload.co.uk

Or if you provide all the details i'm sure someone will show you the results.
You will need to provide a lot of informatio, a caliber and chambering would be a good start.

 

[finnbear270]

I am assuming you are loading calibres above or around .223 / .243, anything like .17 Fireball ..22Hornet 'K' sized cases Err on the side of caution, minute increases in charge weights can alter results greatly.

 

[Laurie]

"Start at the minimum load and work up..."​

The problem with this frequently quoted phrase is the degree of variation between companies' data and practices on defining 'minimum'. For instance, Norma's No.2 manual sees only 1.6 to 2.3gn reductions from max for the three powders quoted for the 150gn Nosler BST in 308 Win - a mere 4% reduction for one. Hornady regularly has its lowest listed loads at well over 15% below max, sometimes over 20%.

Back in the days when Hodgdon powders came in cardboard cylinders, the company only gave max charge weights and advised using a 6% reduction for starting loads (bar H110 which saw that figure reduced to 2%). IMO, that's about right - certainly 10% tops. Hodgdon changed its practices though, no doubt because it didn't fit the treat-everyone-as-an-idiot requirement of modern health & safety practice and US citizens' propensities to sue suppliers should anything go wrong.

On weight increments, Sierra advised 1% of the max listed weight many years ago, which seems about right so 0.5gn for 308, 6.5X55, 7X57 etc. I use a version of what @Craigsaun suggests, especially on breaking ground with new to me powders and/or cartridges. That is, start fairly low with relatively large initial increments to get a feel for MVs, pressures, clean burning etc, then the increment size drops as maximum is approached to 0.3 or 0.4gn for 308 size cartridges / 0.2gn increments for the last few on 223 size designs. Using the lowest listed charge in some manuals for even three round batches as per Hornady will see barrels shot out )) by the time a decent load is finally achieved. I joke, but the reductions are way over the top if you pardon the mixed metaphor.

 

[SimpleSimon]

Thanks for the info so far, largely as I'd assumed, although like everything with reloading it never takes long to complicate things further

I wasn't necessarily looking for specific info, but as a few people have mentioned it and I'm obviously grateful for any info I can take, I'm looking at 308 loads using Barnes TTSX 130gr and Ramshot Wild Boar powder.

 

[7Miller]

I start at 5% below book max and work up in 0.4gn increments.
I hope to find 2 or 3 in a row that have the same POI and then load a sample batch in between that range. In theory I have a 0.2gn cushion either side of my charge load and stay in the same POI. For instance, 45.6gn and 46gn of Viht N140 gave me identical points of impact, with 45.2gn and 46.4gn not being much difference either. So I loaded a batch at 45.8gn and did a seating depth test and get the loads I'm happy with. I've found it the easiest way to get what I'm after, which is half MOA or better at 100 yards.