Discrepancy between loading manuals

[dcali]

It has pretty much been proven that bolt lift, flat or cratered primersand enlarged cases are not a reliable source for pressures. More times than not way into the danger zone.
I watch the chrono and if there is no gain for powder added, that is a max.

I disagree strongly with this. No one pressure sign is reliable, but you can get a sense as you start to see them in combination with reloading manual data and a chronograph. You have to pay attention to everything. Even if your primers are lying to you (which I agree is common), you can wreck a match blowing them, which is another way of saying that the pressure is too high.

And I would *never* use a velocity “flat spot” as a pressure indicator- more powder means more velocity. You can keep increasing it until you blow the case apart before seeing a flat spot.

 

[Big Mc]

Why are the loads for the same bullet and powder different in different manuals? I understand barrel length is part of it but often there is a wide spread. I noticed the Hornady manual is way lower than Lee and Lyman is somewhere in between. Lee starting loads are often near max loads in Hornady. Hodgdon is usually somewhere in the middle. Sierra like Hornady is on the low end. Is it dangerous to use Lee?

From what I can tell. They all have different lawyers ....

 

[JSH]

I disagree strongly with this. No one pressure sign is reliable, but you can get a sense as you start to see them in combination with reloading manual data and a chronograph. You have to pay attention to everything. Even if your primers are lying to you (which I agree is common), you can wreck a match blowing them, which is another way of saying that the pressure is too high.

And I would *never* use a velocity “flat spot” as a pressure indicator- more powder means more velocity. You can keep increasing it until you blow the case apart before seeing a flat spot.

I think you missed the point?
Flat primers, cases swelling at the web and hard bolt lift.
Any of these you can well be WAY over and into high pressure.
I did not or do not mean to say a flat spot has anything to do with pressure.
And my comment on max loads with a flat spot. If I am working a ladder and I get the “flat” spot on the chrono with zero gain that is where I stop. Your just throwing powder out that has not burned.
I am referring to book loads. I have worked up loads in the past with combos that went “flat” before what published book data says.
I have seen it more in magnum pistol loads.
Bottom line on pressure, if you don’t have real equipment to actually measure, it is all guess work

Now if you want to talk wildcats or minimum chambers and throats, that’s another thing completely.

I am all ears here. If a body can’t learn something every day no matter what or how small, pretty bad off.
I think once again how it is typed and how it is interpreted can be two or more different things.

 

[dcali]

I think you missed the point?
Flat primers, cases swelling at the web and hard bolt lift.
Any of these you can well be WAY over and into high pressure.
I did not or do not mean to say a flat spot has anything to do with pressure.
And my comment on max loads with a flat spot. If I am working a ladder and I get the “flat” spot on the chrono with zero gain that is where I stop. Your just throwing powder out that has not burned.
I am referring to book loads. I have worked up loads in the past with combos that went “flat” before what published book data says.
I have seen it more in magnum pistol loads.
Bottom line on pressure, if you don’t have real equipment to actually measure, it is all guess work

Now if you want to talk wildcats or minimum chambers and throats, that’s another thing completely.

I am all ears here. If a body can’t learn something every day no matter what or how small, pretty bad off.
I think once again how it is typed and how it is interpreted can be two or more different things.

I see what you mean. I thought you meant “keep adding powder until velocity flattens out and ignore other things.” I see that’s not what you meant now.

I would add that in my experience, you can get primer issues well *below* max pressure. (Which indicates a problem - stuff shouldn’t be falling apart below spec max). I’ve shot an old Swede for example with factory ammo. The primers were absolutely trashed - flat as a pancake. But it wasn’t over pressure. The chamber was just too loose - certainly the headspace was too long. It might have been to big around as well (it was 100 years old, what can you do?). It’s very common for rifles to crater primers at any pressure - I’ve got a Rem 700 that does.

 

[IdahoSharpshooter]

different law firms representing the various companies...?

 

[dolek]

Take all the published data you can find for your bullet . Take the lowest charge and the highest charge,find the charge in the middle...go up and down from there,watch for signs of over/under pressure .Most of this stuff comes from experience ,which when we think back is really just common sense.

 

[Richard Coody]

It is scary to talk about load work up and pressure signs to a new reloader. The reloading manuals are just a guide. Help you pick a safe starting load. From there it just takes experience. I know i have no problem knowing when i am getting close to max. Don't need a chronograph, don't need quickloads, don't need pressure trace. I am looking for an accurate load that won't tear up my brass.

 

[divingin]

I figure the published "max loads" are something less than what the publisher finds as max due to legal liability. They're publishing data that will most likely be safe in *any* firearm out there. In other words, they're publishing a "max" as the load that will allow the weakest serviceable rifle around to survive. Kind of makes sense in a legal manner of thinking.

 

[Fast14riot]

I ran into a very large difference between manuals with 30-06 and Sierra 175smk, Hogdgon lists a starting load nearly 2 whole grains above Sierras max load. The Hogdgon data is dangerously wrong, my starting load was 3000fps using that, with nearly identical components to the listed. I just used a different primer.

 

[D-4297]

I've found when using Hodgden's data , I take the Min / Max numbers , do the calculations , and start my load work-up at 75% of Max Load . Seems to save a awful lot of bullets , cases , and range time . These manuals are nothing more than a "Guide" , as many have said . They are all based on SAAMI spec'd chambers and mostly shorter bullets with less bearing surface area . And almost always based on 24" or 26" barrels . Sounds like a Hunting rifle to me .... And most "Comp" shooters load longer than SAAMI because we have the chamber length built into our guns , and are going after higher velocities , while keeping chamber pressures at a manageable level .

 

[Fotheringill]

From what I can tell. They all have different lawyers ....

Yep.

 

[Fotheringill]

I do, as stated above. Take the highs and lows, go in the middle and work your way up and down from there.