Why the "hot loads"?

MackForce

MackForce

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I am continuing my research into getting started with reloading. I am starting with 308 and 338wm. Im still deciding on what equipment I should pick up first in order to be most cost effective. But on to my question...

Why do people mix up these hot loads? Depending on who you talk to or what you read, it means different things. As far as I can tell, a hot load is the most powerful load that is safe in your firearm? Possibly the most powerful load that your firearm can handle?

Does this not run the risk of damaging the firearm? Why would someone run the risk? Why not just move up calibers in order to facilitate the power you want in the round?

Having said that, I tend to stay away from used firearms mainly because of this very reason. When someone is selling a rifle I want and including reloading supplies I always move on. I don't want someone's science experiment that may have been loaded with hot loads and risk being stuck with a damaged or worn firearm.

How prevalent is the reloading of hot loads? Is it easy to make a mistake and load some hot loads for your firearm without realizing the damage being done?


Thanks for any help you can offer.

Is this ok? Or do the professional reloaders stay away from hot loads?


Mack
 
Always safe loads. Always arrive at a "hot load" by starting low and working up. Sometimes a max load is also the most
accurate in a firearm. I never start at max and only go there if I can't get satisfactory accuracy with lower power loads.
 
MackForce said:
Thanks.

So, as a rookie reloader, how does one arrive at a max load? Different barrels must make a huge difference?

Does each rifle have a max load?
Click to expand...

Say you are loading 308win and 165gr bullets look at the data for that caliber and a 150gr bullet and of the powder you want. Say varget so start at the min load and work your way up to the max listed charge or you see pressure signs. When you see pressure you are done. Back it off and go over everything you found out to find the most accurate load and load that. It may be right near the max charge or mid way. I have found you will have an accurate load in the mid range and another closer to max. I choose the higher velocity one because you need some speed behind it.

If you find a good accurate close to min you might only be getting slightly more speed then a 30-30 and are not getting what a 308 will give. So might as well have bought a 308. That said don't try make a 308 a 300 win mag that will cause some problems.
 
There is a maximum chamber pressure recommended for each chambering. If you exceed this, it is not the manufacturer's fault if it blows up. You have no way of knowing what the chamber pressure of your load is with any precision, but the powder manufacturer does, and gives a conservative maximum amount of powder for a bullet weight. So don't exceed that. Don't even start with it, give yourself leeway and start with the minimum. Don't go under the minimum. Be aware that how far the bullet sits in, what kind of primers you use, temperature, crimping, and probably other things will affect the chamber pressure. Mistakes are bad. You firearm may have a weak chamber or your brass may be weak. Hence the start low and work up.
Again, mistakes (such as the wrong powder) are the main sources of trouble. Follow the instructions carefully, don't make stuff up, and have fun!
 
The term"hot load" in itself doesn't mean a great deal. To some people it is a load that is still within the acceptable pressure for the cartridge, but is the maximum load that they use in their firearms. To other people, a " hot load" is one that produces pressure signs , and is obviously above the acceptable pressure for the cartridge. Some people use these loads for hunting, with the excuse that they don't use enough of them to do any damage to the firearm. Personally, I don't use the term at all, and I won't use any loads that produce obvious pressure signs. The maximum load for a particular firearm, varies not only with the firearm, but with the specific lot of components that are used. For that reason, no loading manual can provide a maximum load for all firearms, with all lots of components, regardless of what some people choose to believe. Some loads listed in a manual will produce more than the design pressure for the cartridge in some firearms, and some loads will produce significantly less pressure in other firearms, using other lots of components.
 
How high is up?
You may never know.
Using a chronograph is a fairly simple way to guess at the pressure your loads develop.
Reloads that duplicate factory .308 or .338 will produce +- 60000 psi .
Ejector marks, primer shape and hard to open bolts may only show themselves after you exceed the limit.
 
I will agree, a "hot load" is a completely meaningless term.
When you are starting out reloading, pick out a load from a reputable loading manual, or Hodgdon's on line. start at their minimum load and work up. It is a bit difficult to explain pressure to one not experienced in knowing what they are looking for.
For starters, forget about seeing how much the primers are flattened. There is too much variation in primers for this to be effective, but in particular, every ones idea of a flattened primer varies too much.
Get very used to the pressure it takes to raise the bolt on your rifle, after it is in the uncocked position. The bolts on most sporting rifles #### on raising the bolt handle and this can vary with rifles.
With a normally loaded cartridge shot, the bolt handle should raise with no more pressure than it took with nothing in the chamber.
The minimum loads shown in the modern manuals will be fine, so go up about a half grain and fire another one or two, and so on until you reach the maximum load, as shown in the modern manual or on line chart you are using.
There is about a 99.9% chance that the maximum load shown in your manual will be perfectly fine to shoot in your bolt action rifle and the bolt will open with complete ease.
DO NOT EXCEED THIS MAXIMUM LOAD.
I would highly recommend that you shoot this exact load for a year, without changing the charge up or down. Just get used to it and the trajectory it gives. You may want to alter the seating depth, in or out a bit, to see if that changes the accuracy, but most likely you will notice no difference.
After a year of this type hand loading, if you want to get more out of your rifle, get a chronograph and we will go from there.
Bruce
 
MackForce said:
Thanks.

So, as a rookie reloader, (1) how does one arrive at a max load? (2) Different barrels must make a huge difference?

(3) Does each rifle have a max load?
Click to expand...

You start with the START load in the book, and load 5 rounds in 0.5 gr increments, up to the MAX in the book.


(1) You shoot them off a bench at 100 yards, letting the barrel cool between strings. You watch for signs of high pressure, such as an extractor mark, stiffness of the bolt lift or a flat primer. prepare to bring some ammo home, because it is too hot. Look at the targets for a group that looks better than the others, and then do some more testing in that region with a bit more or less powder and some variation is seating depth.

(2) Each gun is different. I saw a Swedish Mauser that was much too hot with a Start load. barrels with worn throats will often take a grain or more powder than other rifles.

(3) Yes. The big variation is in throat diameter and depth.
 
Don't worry about used firearms. It's not like buying a car. Takes a great deal of abuse to damage any modern firearm.
Look into an RCBS Beginner's Kit. Gives you everything you need less dies and shell holder. And buy a Lyman manual too. RCBS kits come with a manual, but the Lyman book is more versatile.
Max loads are given in your manual. Isn't something you arrive at. Max or near max loads are called hot. It's about velocity, but none will damage your rifle. Above Max loads or below minimum loads can though. Above Max is kind of obvious, but below minimum can cause weird pressures from the powder detonating vs burning. Both are sort of speculative as there's no way of telling if an above max or below minimum load will do anything. Isn't just one or even a few grains either way. Don't worry about one manual saying one thing and another saying something else as Max or Min. Manuals will vary a bit, both brand new books and older ones.
One or two of each load isn't enough. A mag load or 5 is better. And for group only.
60,000 PSI with either a .308 or .338 Win is way over max or factory load. .338 max loads run less than 54,000 PSI.
 
sunray said:
60,000 PSI with either a .308 or .338 Win is way over max or factory load. .338 max loads run less than 54,000 PSI.
Click to expand...
Assuming we're talking about .308 Winchester, the max pressure as rated by SAAMI is 62,000 psi. CIP gives it a max of 60,191 psi (415 MPa converted).
.338 Winchester Magnum has a max pressure as set by SAAMI of 64,000 psi.
You're numbers aren't even close.
 
LUTNIT said:
Assuming we're talking about .308 Winchester, the max pressure as rated by SAAMI is 62,000 psi. CIP gives it a max of 60,191 psi (415 MPa converted).
.338 Winchester Magnum has a max pressure as set by SAAMI of 64,000 psi.
You're numbers aren't even close.
Click to expand...

X2!! As usual, Sunray spews forth erroneous information as if it were gospel.

Dave.
 
Ganderite said:
You start with the START load in the book, and load 5 rounds in 0.5 gr increments, up to the MAX in the book.


(1) You shoot them off a bench at 100 yards, letting the barrel cool between strings. You watch for signs of high pressure, such as an extractor mark, stiffness of the bolt lift or a flat primer. prepare to bring some ammo home, because it is too hot. Look at the targets for a group that looks better than the others, and then do some more testing in that region with a bit more or less powder and some variation is seating depth.

(2) Each gun is different. I saw a Swedish Mauser that was much too hot with a Start load. barrels with worn throats will often take a grain or more powder than other rifles.

(3) Yes. The big variation is in throat diameter and depth.
Click to expand...

:agree: Very good advice.
 
sunray said:
Don't worry about used firearms. It's not like buying a car. Takes a great deal of abuse to damage any modern firearm.
Look into an RCBS Beginner's Kit. Gives you everything you need less dies and shell holder. And buy a Lyman manual too. RCBS kits come with a manual, but the Lyman book is more versatile.
Max loads are given in your manual. Isn't something you arrive at. Max or near max loads are called hot. It's about velocity, but none will damage your rifle. Above Max loads or below minimum loads can though. Above Max is kind of obvious, but below minimum can cause weird pressures from the powder detonating vs burning. Both are sort of speculative as there's no way of telling if an above max or below minimum load will do anything. Isn't just one or even a few grains either way. Don't worry about one manual saying one thing and another saying something else as Max or Min. Manuals will vary a bit, both brand new books and older ones.
One or two of each load isn't enough. A mag load or 5 is better. And for group only.
60,000 PSI with either a .308 or .338 Win is way over max or factory load. .338 max loads run less than 54,000 PSI.
Click to expand...

No. I have tested factory ammo in the lab (I might have the results in my files) that averaged over 60,000 psi. One lot of Winchester Supreme Match comes to mind. And it was within SAAMI limits, so I don't know where you get this stuff from.

If you have an active imagination, you should give writing science fiction a try. You might be good at it.
 
Reloading should be respected but not feared. If you are scared to reload stick to factory fodder. Read a good manual on the signs of pressure and watch for signs. As long as you aren't reloading subcals like the .17s or 20s your rifle will give you warning long before you have to worry about blowing your fingers off. Most of the guys I know that are serious about reloading don't worry about any savings by rolling your own they are trying to get the most they can from the load they are developing. The best accuracy and velocity will have a spot where the two lines cross. Whether your rifle will find it's node at A,V or X on your two lines is part of the fun of developing a load.
 
When you are quoting pressure numbers, dont get PSI and CUP mixed up, they are not the same.
h ttps://www.shootingsoftware.com/ftp/psicuparticle2.pdf
 
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