Posted: 3/9/2026 11:18:11 AM EDT
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I'm most concerned with listed max load values . . . If you have load data from a powder manufacturer for a specific bullet and data from a bullet company on that bullet that may be somewhat different for the specific powder, which do you go with? THANKS IN ADVANCE |
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Originally Posted By JKinAZ: I would work it up the same as any other load and let velocity and pressure signs tell me where the end of the safe loading envelope is. Load data needs to be verified this way no matter what the source is. Agreed, I generally start at the lower 3rd/sometimes middle of the load charge and work up the same way. I've noticed that older publications/books tend to have higher max charges vs stuff I've seen published in the last few years. It probably had something to do with reducing liability. A lot of those older max charges were probably pushing the safety envelope, depending on the gun being used 
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Originally Posted By Pennsilfaanisch: Agreed, I generally start at the lower 3rd/sometimes middle of the load charge and work up the same way. I've noticed that older publications/books tend to have higher max charges vs stuff I've seen published in the last few years. It probably had something to do with reducing liability. A lot of those older max charges were probably pushing the safety envelope, depending on the gun being used I have seen the same, older data seems to allow for a little higher charges and velocity than newer data with some powder/bullet combinations and I suspect you are correct regarding liability. It also helps to remember that load data is developed for the lowest common denominator (rifles with a tight chamber, short or tight freebore, barrels with excessive fouling, etc). |
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Reduced reloading data is the result of more accurate pressure testing equipment, not any liability. The powder and bullet manufacturers assume zero liability regarding our reloading decisions. The last I knew, Sierra doesn't even own basic pressure testing equipment, they use a micrometer to test case head expansion to publish maximum loads. Hornady on the other hand, uses piezoelectric transducer equipment which registers peak pressures more accurately than any other system. They run pressure tests, all day, every day, testing ammo as it comes off their production lines and storing the data for future reference. Hodgdon uses a mix of old school C.U.P. (copper units of pressure) which is useful for establishing average peak pressures and more modern PSI readings which record actual peak pressures like Hornady does. Anyone referencing Hodgdon's data can clearly see that C.U.P. peak readings are 10,000 +/- lower than their PSI readings. The peak pressures are interchangeable; it's the testing system that are different. There has been a huge misunderstanding regarding 7.62x51mm pressures vs. .308 simply because people a comparing 7.62x51mm C.U.P. pressures, which were used by the government, and cross-referencing that data against published PSI pressures associated with commercial .308. They are, in fact within 2,000 psi of each other if tested using the same equipment. Brass and primer selection causes way more pressure difference than most people are aware of. If you develop a maximum load in Winchester brand commercial .308 brass, then load that same charge in Federal commercial .308 brass or worse still, 7.62x51mm Lake City, you are going to experience "issues". This is an extreme example, but the pressure difference when changing components are real and have to be accounted for. I came across some FNM-79 headstamp surplus 5.56mm ammo at a gun show decades ago. The case walls and head were so thick that the empty unprimed cases weighed 107 to 109 grains. 13 to 15 grains higher than typical .223/5.56mm brass manufactured in the USA. Needless to say, a substantially reduced powder charge was used when I reloaded that brass, and I let those cases lay where they fell so as not to infect my stores of good brass. Again, this is an extreme example of what takes place when changing components. Bullets, even if they weight same, create different peak pressures based solely on design. I remember and old article that used identical powder charges, primers, and identical .30-06 cases loading close to twenty different 150 grain bullets seated to the same depth. The C.U.P. pressure reading spanned 15,000 C.U.P. from the highest to the lowest readings. To me, that was amazing. Try to look up some of the testing performed by Wm. C. Davis Jr., he spent his lifetime working as a ballistician for Uncle Sam. |
| in my experience, companies like berger and sierra have multiple reloading experts sitting around waiting for you to call so they can dispense ballistics advice. seriously, they have help lines for load data and the guys that answer are pretty awesome. Almost every time I call, I've spent 30-60 minutes and learned a ton. it's been a few years though, so ymmv |
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the how to for me is , the bullet and powder combo and what i do is choose the powder weight to push the bullet to the speed i want it to go , if it's a short range being 200 and end i don't need to push the bullet to the max charge or fps on the chart . if it's long range i want full charge weight to take as much drop and drift away for the shot . all of my loads are chrono put into Strelok pro , then i may shoot a different rifle but i have a good idea on bullet fps coming out of the rifle /bullet combo TS2 |
All Gave Some / Some Gave All
Maj. Richard Ayers
4-16-70
http://www.pownetwork.org/bios/a/a048.htm
Maj. Richard Ayers
4-16-70
http://www.pownetwork.org/bios/a/a048.htm
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One issue I have with loading manuals from powder or bullet manufacturers is the general absence of +P loads except in certain handgun loadings to replicate +P factory loads and for rifles like .45-70 where there are pressure tiers based on action strength. What I can't find readily is modern action load data for .280 Remington at .270 Win or .280 AI pressures. When Remington published its SAAMI data for the 280 it deliberately set pressure below that of the ,270 Winchester and many other similar cartridges. Presumably the early 740 Remington semi-auto action did not like higher pressure. Fast forward to the ,280 AI which has SAAMI spec 65000 psi. In the same rifle, such as a good Remington 700 action, there should be no reason not to load "full power" 65000 psi for the "regular" .280, as also with .270 Win. Published load data at 65000 psi for .280 Remington would close much of the gap between it and the AI variant, as the case capacity is really not much greater. I think the main difference is chamber pressure. I have an exceptionally accurate .280 Remington chambered Rem 700 Custom Shop rifle. I see no reason to chamber it to AI and possibly degrade both accuracy and collector value. Where might I find 65000 psi load data for .280 Remington? It could be considsred a safe "+P" load. Loads worked up to maximum for 140 and 150 grain bullets t show absolutely no pressure signs, no should they at the lower SAAMI pressures. |
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Originally Posted By borderpatrol: The last I knew, Sierra doesn't even own basic pressure testing equipment, they use a micrometer to test case head expansion to publish maximum loads.  Completely FALSE INFORMATION… I worked as a Quality Control Inspector for Sierra Bullets for 3 years, mid-2021 until mid-2024. The last 2 1/2 years of that period, I was actually their Ammunition Inspector. I know they had a dedicated Pressure Lab for at least several years prior to my employment there and they still have it as of now. |
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Originally Posted By bluezerosix: Completely FALSE INFORMATION… I worked as a Quality Control Inspector for Sierra Bullets for 3 years, mid-2021 until mid-2024. The last 2 1/2 years of that period, I was actually their Ammunition Inspector. I know they had a dedicated Pressure Lab for at least several years prior to my employment there and they still have it as of now. This is wonderful information. Knowing which bullet or powder makers use the same kind of data as everyone else helps in comparing published loads across different sources. Quite a while ago I noticed how many load data sources might list the same cartridge with the same (literally) bullet and powder, but publish very different velocities and (if they include these) pressures. That got me looking closely at other data in these manuals, specifically OAL and “test firearm”. When you see the same bullet/powder/cartridge combo listed with different velocities, look closely at the OAL, especially in pistol cartridges. A change of 0.10” in OAL (and thus seating depth - which changes available case volume) can make a huge difference in pressure, which will in turn change the bullet’s velocity. What you posted is critical information for someone who is trying to make sense of the differences between different sources for “the same load”. A load that came from fully tested - velocity and pressure - lab load can only vary by a very few mechanisms. Comparing data from a “full lab” source with data from a “we saw no pressure signs” source is far more likely to confuse a handloader without any real way to understand the differences. |
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Some here are not astute reloaders can not discern various details perusing load data sources. This is prime example of parsing out the details: Brass and primer selection causes way more pressure difference than most people are aware of. If you develop a maximum load in Winchester brand commercial .308 brass, then load that same charge in Federal commercial .308 brass or worse still, 7.62x51mm Lake City, you are going to experience "issues". This is an extreme example, but the pressure difference when changing components are real and have to be accounted for. The brass as mentioned above is one the biggest variables when load data generated. There hurdle is some here do not want to do a proper load work up using the components that they have observing for signs of pressure as you do your own leg work. So many of you chase the wrong thing, velocity. Accuracy is the end goal. No game animal is going to know if they were harvested with a round with a muzzle velocity of 2800 FPS or 2950 FPS. Ethical hunters are going to know the limits of their skill set, rifle, and preferred ammo. |
jme and I am a NRA Endowment Member
Don't be too timid and squeamish about your actions. All life is an experiment. The more experiments you make the better.
R W Emerson
Don't be too timid and squeamish about your actions. All life is an experiment. The more experiments you make the better.
R W Emerson
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As stated several times: Start lower and work up. Watch for signs of pressure. I always use a chronograph. It’s another tool in the process: keep velocity in the normal for that cartridge. I see too many people trying to squeeze another 50 FPS….. which is really not worth the squeeze if it puts you into dangerous pressures. |