Reloading Components Question

[jbirdwell]

Please understand this question is being asked by someone new to reloading. Say you have load data for a specific bullet and powder but are using different brands brass or different primers. How do you decide where to start for your powder weight?

The opposite of that would be if you have, say a 140 grain 284 bullet but don’t have load data for that specific bullet in your caliber, how can you determine a safe starting point with the components you will be using?

Thanks ahead for any clarification provided.

Jaye

 

[SDPlinker]

Always start at the bottom of the ladder and watch for over pressure signs .

 

[375er]

Mostly, but not always you can use data a guide instead of an exact "recipe". 140 gr bullet is a 140 gr bullet. Always start at the low end of a particular load and work your way up. Check for pressure signs as you go. If you change any one component drop back down and work up again.

 

[USMA84DAB]

This situation is why one is wise to find many different reloading manuals.

I can offer my approach. YMMV. I am not a doctor, nor did I stay in a Holiday Inn Express last night.

As an example - I recently reloaded .45ACP. The 2003 Hornady manual gave a load of 6.8 (?) grains of International Clays for their FMJ 230 grain projo, yielding 900 FPS. I chose 6.1 grains to attain 850 FPS. This leaves me adequate space in charge/pressure for a clump of powder dumping into a case by mechanical error. It also is plenty of fudge room for the tiny bearing surface difference between old style Hornady FMJs, the current production FMJs, and the current production XTP hollow-points. I do not chase the maximum last few feet per second. Especially with pistols, the ranges are so short that trying to flatten their trajectory is meaningless.

Rifles are another level of power to respect. Some buddies here on AH have provided QuickLoad data to determine charges to load from. I like to take not the fastest harmonic node, but the next one down. This way I steer clear of the pressure limits, whilst providing for myself breathing room for things such as errant oil in the bore, a robust powder dump, a longer bearing surface on the Swift bullet vs. the data's numbers for the Barnes projectile, etc.. Then it becomes an exercise in testing the load to insure the rifle likes it, you like it/can tolerate the recoil, and then tweak it for the final few grains of powder up and down to find the absolute sweet spot harmonically.

Past these generalities, you would have to ask specific questions. There are a ton of hacks one accumulates from decades of reloading, so at some point, you need a live voice mentor via F2F or phone. Maybe this will get you started though.

 

[Firebird]

I don’t like that 140 grain bullet comment-a Barnes ttsx is a different bullet than a Sierra 140 pro hunter. Find the load data for the bullet you have chosen and work up from the bottom as previously stated. Seating depth is another consideration as well

 

[Hogpatrol]

Please understand this question is being asked by someone new to reloading. Say you have load data for a specific bullet and powder but are using different brands brass or different primers. How do you decide where to start for your powder weight?

The opposite of that would be if you have, say a 140 grain 284 bullet but don’t have load data for that specific bullet in your caliber, how can you determine a safe starting point with the components you will be using?

Thanks ahead for any clarification provided.

Jaye

Best practice, use bullet manufacturers' manuals, stick with one brand of brass, use primers shown in manual, change primers when one doesn't work.

 

[JimP]

When it comes down to it get a hard copy book manual for the bullets you plan to use and READ IT. Just don't skip to the recipes but start at the first page. All the manuals that I own have sections on everything that you need to know.

 

[Joker12]

Even using the exact components listed in a good Manual always remember that that data is only the gospel in the firearm or test barrel that they were using in exactly the conditions that that it was tested in. There are many variables, just considering manufacturing tolerances that always exist in any machined product can make 2 seemingly identical loads or rifles perform differently. That's why we "work up" safe accurate ammo for individual firearms. As others have advised start with listed starter loads and let your rifle tell you what it likes. Be safe and enjoy the process.

 

[Ray B]

Regardless of what the loading manuals say, when I start determining a starting load for a cartridge I get out my Powley Computer slide rule. measure the water capacity of the cartridge, measure the effective length of the barrel and process the calculation. I then compare the result with loading manual loads. I'll check the maximum loads listed for those that come closest to 100% load density. From those I'll pick a starting load and go from there.

 

[jbirdwell]

Thanks everyone for the tips

 

[Desperatezulu]

Some good advice above.

Short of employing a pressure strain gauge, none of us knows exactly what the pressure is of our reloads. Nobody wants to blows themselves up unwittingly. Therefore the best measure of pressure short of actually measuring pressure is muzzle velocity. In other words a chronograph of some sort is invaluable to the reloader.

Relying on 'pressure signs' presenting on the fired case to determine when you're in the danger zone is sketchy at best, particularly for the inexperienced reloader and/or a new calibre.

Manuals are somewhat useful but are generic at best and the apparatus used (powder batch, bullet, primer, case, case volume, trim length, barrel length and chamber dimensions) is unlikely to all match yours exactly. Not to mention ambient conditions between the test environment and yours. Any variation in one parameter can significantly change how your load performs.

Say you have load data for a specific bullet and powder but are using different brands brass or different primers. How do you decide where to start for your powder weight?

My answer to this is "Firstly, you take note of what the max prescribed muzzle velocity is (in your manual. Or ask someone with internal ballistics software to check for you). You back off the powder charge by at least 10% and shoot over a chrony and see where your velocity is. If it's above the max velocity, you back off the load even more, and repeat. Otherwise, build up in increments until you find your desired velocity and/or a load that groups very well"

The full fat version is to measure all of your components precisely, ensure consistency in your loading, including all components and processes, use GRT or QL to help model your load and then record your velocities meticulously. Rinse and repeat til you find your happy load/velocity/group.