Data discrepancy

Here is the one and only thing that you have to remember about these things.

THEY ARE NOT HARD FACTS. THEY DO NOT HAVE TO BE TRUTH. THERE IS NO LEGAL OR MORAL OBLIGATION TO PROVIDE DATA THAT THEY FEEL IS INAPPROPRIATE FOR THEIR PRODUCTS. THEY CAN PROVIDE ANYTHING AT ALL, AND NOT VIOLATE ANY LAWS OR BUSINESS ETHICS.

Got it? If sierra chooses not to provide data for their own bullets that might cause problems for them in the future, that is exactly what they should be doing.

Now, with the internet, any doofus with a modem can get a wild hair up his hind end (I.E can I load my .600 Nitro with Bullseye or Red Dot?) If he spends an hour online searching, no matter what the question is, somebody will tell him that it's just fine.

how much tequila can I drink and still pilot my plane?
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As much as you want to, as long as you're just the co-pilot.
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So here's the end of the story. You go among sources that you believe with all your heart are reliable. Then, from those sources, you choose whichever data set gets your gizzard all aflutter. If you follow this data to the letter and absolutely correct processing, you should be safe, and have good ammunition.

Should you do anything wrong, or even do everything right, you might have a problem. Just so you know, that part at the beginning of the books or web pages? It says that if you have a problem, well, it's your own problem. They provide the data as a service and that there are no guarantees.
 
"...their paid app..." Isn't a manual. It's, at best, a guess. So is Quickload, which does not verify anything, never mind pressures.
In any case, all manuals will be slightly different. The reflect averages of all the loads tested(computer programs do not test anything) using the exact components(Hodgdon tested with a 1 in 10, 24" barrel with Winchester primers) and conditions on the day of the test.
You'll also note that they used PSI vs CUP. There is no mathematical conversion between those different methods of measuring pressure.
Kind of surprised SAAMI Max for the .270 is 65,000 PSI. The IMR4955 Max load runs 62,900 PSI.
"...load was copied from a friend..." That load has nothing whatever to do with your rifle. You're basically using somebody else's reloads. And H414 does not require or demand magnum primers.
 
T. O'Heir said:
"...their paid app..." Isn't a manual. It's, at best, a guess. So is Quickload, which does not verify anything, never mind pressures.
In any case, all manuals will be slightly different. The reflect averages of all the loads tested(computer programs do not test anything) using the exact components(Hodgdon tested with a 1 in 10, 24" barrel with Winchester primers) and conditions on the day of the test.
You'll also note that they used PSI vs CUP. There is no mathematical conversion between those different methods of measuring pressure.
Kind of surprised SAAMI Max for the .270 is 65,000 PSI. The IMR4955 Max load runs 62,900 PSI.
"...load was copied from a friend..." That load has nothing whatever to do with your rifle. You're basically using somebody else's reloads. And H414 does not require or demand magnum primers.
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Their paid version of their app is a manual. Its the constantly updated version of their reloading manual. You have instant access to updates instead of waiting for the new book.
 
"...load was copied from a friend..." That load has nothing whatever to do with your rifle. You're basically using somebody else's reloads.
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No different from taking the Accuracy load out of Lyman, I was using a load proven by a Master class shooter. I had to start somewhere with a new rifle. It worked so I stayed right there.

And H414 does not require or demand magnum primers.
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It sure as hell does in MY Ruger M77V if I want it to shoot as accurately as W760... or any of the other powders that are satisfactory in THAT rifle. Did you read the long treatise on how every combination is different?
 
In a phone conversation with a ballistic engineer at Lake City arsenal back in the early 1970's about their 7.62 NATO M118 match ammo, I learned their various bulk production lots used near a 3 grain spread in average charge weights of IMR4895. They have to meet the maximum average pressure 50,000 cup, 2640 +/- 30 fps velocity and 3.5" mean radius (about 18" extreme spread with 3 or 4 different lots of 173-grain FMJBT bullets.

Commercial canistered powdered lots typically would have half that spread. They're made with blends of bulk production lots. Which makes load development easier for reloaders
 
CAUTION: The following post includes loading data beyond or not covered by currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assumes any liability for any damage or injury resulting from the use of this information.

I have shot in the same 7.62 NATO barrel, M60 proof loads with the same lot of primed cases and powder used in M80 service ammo shot for comparison. Most people looking for visible high pressure signs didn't think the fired proof load cases were too high in pressure.

Actual pressure differences are about 17,000 cup or 21,000 psi.
 
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Bart B. said:
CAUTION: The following post includes loading data beyond or not covered by currently published maximums for this cartridge. USE AT YOUR OWN RISK. Neither the writer, The Firing Line, nor the staff of TFL assumes any liability for any damage or injury resulting from the use of this information.

I have shot in the same 7.62 NATO barrel, M60 proof loads with the same lot of primed cases and powder used in M80 service ammo shot for comparison. Most people looking for visible high pressure signs didn't think the fired proof load cases were too high in pressure.

Actual pressure differences are about 17,000 cup or 21,000 psi.
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Not surprising. Imho anything, short of catastrophic, other than using a Mic on the brass is too subjective to be trusted. A guy I shoot with was still "working up" (literally up) his load way after the extractor flat spot was removing the writing from the case back. I will concede, the primers still looked good and the bolt was not "too sticky".

That stuff annoys the mess out of me. If you want a 7STW buy a stw, dont try to turn a WSM into one.
 
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