How do you decide which max load is the real max load?

[guns are dumb]

So, new guy to reloading....

I've got Lyman and Hornady reloading manuals, reloading for .357 using 125gr HP-XTP bullets and Vihtavuori N110.

The Lyman manual shows the max load as 17.5gr (compressed) with a 38,500 CUP. The Hornady manual shows a max load of 16.1gr with no pressure stated and the Vihtavuori reloading guide on their site shows a max load of 18.4 grains with no pressure stated and a starting load of 16.8gr (above the Hornady max load).

I'm starting at 15.5gr, but how do I decide where to stop? Of course, this question isn't just directed at my particular problem, but how do you guys go about making a decision as to where the max load actually is?

 

[tyromeo55]

I take loads from multiple verified sources and come up with what I think is a good starting load ( not max ) If I think i need to go up from there I do gradually and watch for signs of pressure until I get where I want to be.

This applies to modern guns only. And until you get a lot more comfortable ( and maybe nor then even) I would not stray from the listed powders and loadsFrom my books or data directly from the powder mfg

 

[338Shooter]

Work up until you see pressure signs in your guns. The published max loads have lawyers attached to them.

 

[Blitzfike]

I look for pressure signs, flattened primers, cratered primers, and in extreme cases, loose primer pockets. I ALWAYS use a chronograph when working up loads and use the published velocities as a benchmark for my development. I usually stop when approaching factory velocities, except when working up loads for pistol caliber carbines with slower burning powder. I can usually exceed the published velocities by 2 or 3 hundred fps by using a slower powder in a carbine length barrel while still keeping pressure signs in the normal range. Pressure spikes can occurr with very small changes in powder charge or seating depth. Bullets with more bearing surface or harder jacket material can also boost pressures. If you have someone close to you who is an experienced reloader, get with them and have them show you what to look for in pressure signs. Good luck and be safe.. Blitzfike

 

[guns are dumb]

I like the data in the Lyman manual the best, I've started using it. My load is just just slightly over the suggested starting load. I don't have much interest in replicating the extreme max loads, but being that the max loads are substantially different, I'm just trying to figure out where I should be.

Interestingly, the max load for .44 mag seems to be relatively consistent, which is another caliber I'm loading in.

 

[streak]

Manuals as you see can disagree with each other all the time. Like the others have said, watch for pressure signs. Brass that is hard to extract is another overpressure sign that they didn't mention if the rounds don't easily fall back out of the revolver (i'm assuming thats what your shooting) after being shot. Also always inspect your brass, esp the first few load ups, for bulging and splits.

 

[Shadowrider]

I would lean towards the Vihtavuori data being a true max. They seem to not have the legal staff involved in their data publishing. Yet...

But you will have to work up to it gradually with your individual components and guns.

 

[jtischauser]

good stuff. Im listening intently as im just starting to pull the handle too.

 

[Rod Snell]

We often talk about max powder loads and forget to read the fine print about what primer, case, and specific bullet was used, as if none of this mattered. A change in primer can add 5,000 PSI.

If any component is changed from the original recipe, than the pressure produced will change, sometimes significantly.

In straight-walled pistol cases, particularly cartridges with low pressure SAAMI specs (like .38 special and .45 Colt) the first definitive pressure sign may be the topstrap hitting the ceiling. "Reading the cases" as is done in high-pressure rifle cartridges does not always work.

 

[Shifty]

Watching for pressure signs is obviously a good way to go, but if I have to go with what someone else has to say, I always follow the powder manufacturers specs.