Start Low & Work Up?

[pertnear]

I've been reloading for many years & have followed the start low & work up to max on powder charges for safety. The rule use to be take the max & reduce it by 10% for a starter min load. Magnum cases are worked up to max in 1 gr increments. Med capacity cases ~.5 gr increments. Small cases in <.2 gr increments. Most load data is now specified in min/max numbers. Are there any adjustments for other factors to consider? What rules do most reloaders follow getting to max?

 

[Webster]

I've been reloading for many years & have followed the start low & work up to max on powder charges for safety. The rule use to be take the max & reduce it by 10% for a starter min load. Magnum cases are worked up to max in 1 gr increments. Med capacity cases ~.5 gr increments. Small cases in <.2 gr increments. Most load data is now specified in min/max numbers. Are there any adjustments for other factors to consider? What rules do most reloaders follow getting to max?

Sounds like you have a good safe procedure.

My 6BR and 6BRX for GH hunting have followed the reloading manuals pretty close. Both are Rem700 actions. I judge pressure by experience observing primer edges flowing into the FP opening and I always get ejector swipe when nearing max load. . Once I get 1 shot with these signs I back off about 2 grains. 10% is about 3 gr backoff on a 6BR. I pick a powder in the manual that is common and gives good speed. Then develop a load based only on accuracy. A Kreiger barrel really helps in the accuracy department.

 

[Leo_B]

I'll be loading later this year. When I do my plan is to take 5 steps from min-max. I won't ever go beyond step 3 I imagine as I just don't need max speed and definitely not max recoil. Anyway, if the max is 2.0gr above the min I'll divide that by 4 and get .5 so my steps will be 2.0, 2.5, 3.0, 3.5 and 4.0 giving 5 steps from low to high for a 2.0-4.0gr recipe. It would be the same 0.5 steps if the recipe was 16.0-18.0gr. If the recipe has a wider gap I may rethink as that would be big steps but I only plan to load the revolver .32's and .38's and .22 Hornet and .30 M1 carbine so that system will probably work for all those. I hope it makes sense. It does in my cranial vacuum chamber.

 

[cem]

I have a jig for measuring case head expansion to half a tenth - I bought it when one of the majors was endorsing this to have an idea of pressure. I don't much use it anymore as I found it some indication but lots of "noise." These days I start with a load close to where I expect to end up. Maybe a manual accuracy load, a universally ( well almost universally) accurate load, or an almost top velocity manual load with the components I'm using. I fire through 35P screens . I check for pressure signs but I don't try to read them; I do read the screens. Match the manual with adjustments for barrel length and I'm done.

 

[K22]

I don't know what "most" reloaders do but my process for load development is similar to yours.

Whenever possible, I try to use the bullet manufacturer's published reload data since I consider bullet selection critical from both an accuracy and terminal performance standpoint. In my experience, if a rifle likes a specific bullet, then often a range of suitable powders will often work well.

I believe it is critically important to learn to read pressure signs if you are reloader. I have often found that the most accurate load is not the maximum load published.

Keep in mind that if you change components from the published data, it can result in a different pressure curve. Even if you use the identical recipe, different firearms can react differently to the same load. In addition, changes in seating depth can affect pressure and performance.

 

[LCazador]

I've been reloading for many years & have followed the start low & work up to max on powder charges for safety. The rule use to be take the max & reduce it by 10% for a starter min load. Magnum cases are worked up to max in 1 gr increments. Med capacity cases ~.5 gr increments. Small cases in <.2 gr increments. Most load data is now specified in min/max numbers. Are there any adjustments for other factors to consider? What rules do most reloaders follow getting to max?

You're leaving out a very important factor and that is fireforming new brass. A 10% under max load can distort and expand brass beyond desirable specs especially when you start with a bunch of new cases that are short of your chamber and have exponentially more headspace. This happened to a friend with a 300 PRC. That load turned out to be way too hot and he wound up losing the brand new Atlas brass. So start with a middle load or a load 20% under max for fireforming then proceed to work up a load with the fireformed brass. And do this with a few pieces not all 100 pieces that you bought.

 

[charlie b]

I used to use the Sierra data for most of my loads (I mostly used SMK's). I'd duplicate theirs, including OAL, usually near max. It would get me a decent load most of the time.

Then I got a chronograph and found I was pretty far off vel from the book, 100fps or more. At one time I had the exact rifle and components in the Sierra manual for .308 (Savage BVSS). Even used the same cases and powder. The book loads were still off by a lot. FWIW, Hodgdon data showed at least 1gn more powder and was closer to my results.

Then I started playing with seat depth more. That changes things a lot more than you might think, even in medium size cases. Now I use book loads, set the data in GRT to determine how close the model is. Then use the model with my longer OAL to determine my loads. First time out I take my data and update the model. It is at least as close or closer than book data to my measurements. It allows a prediction of what happens with changes in seat depth as well as charge. The bonus is you can see how close you are to max before you see it in the rifle. I get predictions within 50fps of actual and sometimes better.

I don't shoot big cases (.223, 6BR, 6.5CM, etc) but I've never had a problem shooting higher level loads in new brass. Haven't fireformed a wildcat in many, many years.

 

[357Mag]

I've been reloading for many years & have followed the start low & work up to max on powder charges for safety. The rule use to be take the max & reduce it by 10% for a starter min load. Magnum cases are worked up to max in 1 gr increments. Med capacity cases ~.5 gr increments. Small cases in <.2 gr increments. Most load data is now specified in min/max numbers. Are there any adjustments for other factors to consider? What rules do most reloaders follow getting to max?

Pertnear -

Howdy !

My rifle re-loading has mainly been performed to provide dedicated ammo for rifles that
are/were chambered for “ wildcats “ of my own design. I have performed a lesser amount of reloading for a couple of .35 Remington, but for those ….. I develope accurate loads that feature “ reduced charge “ weights, and not loads that operate near max pressure.

My safe process:
To ensure I developed loads that operate w/ safe pressures, I first review case capacity and loads for known cartridges of the same caliber; that bracket the case capacity of my wildcat.

I’ll pre-load my wildcat test charges at home, then identify, label; and segregate them in separate storage containers. Focusing on one particular bullet/bullet wt….
I start my wildcat’s load development w/ a powder/charge that has shown to be safe in the smaller capacity case ( mentioned above ). This starting point charge wt is typically within * 2gr of the final charge wt I’ll finally adopt ( once range testing is completed ) for shooting that powder in my wildcat case. IMHO - a 2gr span for potential final powder charge wt to be adopted is already pretty close to the maximum point. For this reason,
* I approach max charge wt by going up in charge wt from the starting point in first in .2gr increments, and watch for pressure signs as I fire each test cartridge….. starting with the lowest charge test cartridge first; and then and go on to the next incremental charge.

Once ( or if ) I have advanced a total of 1gr in test cartridge charge wt and have not topped out on pressure, * I slow all remaining powder charge wt increases to just .1gr increments…. aiming to find the max, safe charge. I have often found ( while testing new powders out ) that I don’t even get to fire the last 4 or 5 pre-loaded test cartridges….
as I have crept up on the max charge carefully; and the max charge was soon determined.

After finding max charge wt:
For safety sake, and as an accommodation to my eventual use of these wildcat cartridges on groundhogs in warm/hot humid weather: I’ll write down the max charge wt for the powder & bullet in my loading book as being .1 or .2gr below the proven safe max charge wt shown in testing.

Accuracy:
* With the max charge wt for that caliber & bullet recorders, I thereafter assemble my next batch of test case charges… were I reduce charge wt down in .1gr increments…
until best accuracy is achieved, shooting 3 shot groups @ 100. When one of these charges gives the accuracy level I’m looking for, I verify by shooting a 5-shot group.

With my .224” cal and 6mm cal wildcats, the accuracy charge is often not very far below the max pressure charge. In my “ DEEP 6 “ wildcat, best accuracy was found ( for all bullet weights I tested ) to be right @ or very close to max charge wt, when shooting
s-l-o-w-e-r “ burn rate “ powders like RL-22, IMR7828 ( and 7828SC ); and RL-26.
( DEEP 6 has 51.2gr H2O capacity ). I also was using FED Magnum Rifle Match primers.

For the reduced loads in .35 Remington ( Marlin M-336XLR and CVA “ Hunter “ ) I first very thoroughly read up on “ Secondary Explosive Effects “.( S.E.E. ).
What I learned by reading magazine and book articles years ago, was greatly augmented by the wealth of information one can pull from the web; especially by conversing w/ those knowledgeable on the subject of S.E.E. @ this website.

YRMV


With regards,
357Mag