Pressure, how high is too high ?

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updatelee

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Im using the QuickLoad software and I have to say, Im really impressed. Ive got a brand new this year Rem 700 300wm 26" barrel.

using winchester brass and cci br2 primers, 208gr amax, COL is 3.646 thats seated right on the dot in the lands. I had R22 at home so thats what I was using, I realize its not perfect for this weight. 73.0gr

QuickLoad is putting my pressure at 60533 max is stated at 62366, quickload states my est fps at 2858 and my 10 test loads ranged from 2842 at the bottom to 2855 at the top. so im impressed with how close it got me.

now my question is my loads are not showing any signs of over pressure, they extract fine, no sticky bolt, primers look fine no flattening. goto 74.0gr and im over the max presure and only 40fps faster. what Im wondering is are these max pressures underrated ? to protect against people using cheaper made actions or older etc ?

Can I keep working the load up carefully, 0.5gr at a time, to see what my groups show ? or should I call it quits when quickload tells me to ? hehe.
 
It's not how much pressure you jack that thing too, its where it is the most accurate, backing them down a few grains some times helps more than hindering them, Had a Ruger 06 that I tried to load high and found out it shot better backed down 2 1/2 grains. Just my thoughts.
 
With the small spreads you are getting there I think that's the sweet spot, from there for more accuracy I would play with seatin gdepth.

BTW, I have found re22 is the best and most consistent powder in my 300 win.
 
It's not about thinking a computer program that gives you some numbers. The quickload program is an approximation of what should happen. It does not take into account lot to lot diffrences in powder burn rate, diffrences in primer lots, nor the varied and numerous things that could make your rifle of diffrent spec from the test barrel used to manufacture their program.
It's the same as relying on bolt lift and primer flatness as a pressure indicator. It is un reliable and dangerous. usually by the time the overt pressure signs often discussed are showing you have likely entered the relm of 25% or better over maximum design pressures.
Lets see. 65,000psi x 25% thats 81250fps.
Hmm a single proof load only does 72,000psi.
So after a few hundred loads of say 75,000psi, you have your action come apart because of cumulative metal fatigue.
Ya it was really worth it huh.
Think about it.
 
You cannot load to a specific pressure because when you are at a maximum load levels small increments of propellant make huge changes in pressure. A better plan is to work up your loads using a chronograph. Watch the velocity changes as you incrementally increase your loads. When the velocity plateaus you have gone as far as you should, and the next increment or so will result in a sticky bolt. Increments should be half a grain with small capacity cases and one grain for large capacity cases. Instead of getting 50 fps more velocity you might see that you only get a 20 fps increase - that is the plateau. It works with every cartridge I load in both rifles and handguns. Typically, I consider the load below the plateau as maximum rather than the load that plateaus.

Here is an example of how it works. The figures are from a load I worked up for a .308. Each subsequent round was loaded in 1 grain increments:

46 grs - 2528 fps
47 grs - 2566 fps (38 fps)
48 grs - 2603 fps (37 fps)
49 grs - 2644 fps (41 fps)
50 grs - 2662 fps (18 fps)

The velocity shows a similar increases with each increment of propellant but when maximum pressure is reached, the velocity increase drops off sharply.
 
Lefty #### said:
It's not about thinking a computer program that gives you some numbers. The quickload program is an approximation of what should happen. It does not take into account lot to lot diffrences in powder burn rate, diffrences in primer lots, nor the varied and numerous things that could make your rifle of diffrent spec from the test barrel used to manufacture their program.
It's the same as relying on bolt lift and primer flatness as a pressure indicator. It is un reliable and dangerous. usually by the time the overt pressure signs often discussed are showing you have likely entered the relm of 25% or better over maximum design pressures.
Lets see. 65,000psi x 25% thats 81250fps.
Hmm a single proof load only does 72,000psi.
So after a few hundred loads of say 75,000psi, you have your action come apart because of cumulative metal fatigue.
Ya it was really worth it huh.
Think about it.
Click to expand...
ok thats what I was wondering about.

Im more concerned about accuracy then presure as I think anyone is. Basically what quickload was telling me was different then I had been reading elsewhere. seems much of what im reading states if you hit signs up pressure in your cases then back it off a little.

but I was playing with some load data I had done myself on 178 amax and was quite surprised to see my pressures.

75 gr of r22 on a 178 was where I was getting my best accuracy but that was at 59430 moving higher to 76 and 76.5 my accuracy quickly opened up, and quickload shows these loads in the red at over pressure. but my brass wasnt showing any signs, primers were fine, none were flattening or loose. Brass wasnt fine, no cracking, no sticky bolt.

So basically what Im reading out of these reply's is if your getting pressure signs on brass/primer then you are WAY too hot.

btw Ive got a crono, one of the chrony beta masters, I really enjoy the remote lcd, Id recommend that (master version) to anyone using a larger shell like the 300wm. I gota put that thing 15-20ft away or it blows over. at that distance I couldnt read the lcd on the non-master lol.
 
The program and what you read cannot address any variables resulting from your equipment. May be reasonably accurate guesstimates, but I don't think that you should expect any better, or place absolute faith in them. Rather than depending on primer appearance, bolt lift, etc, use a good micrometer (not a caliper) to measure the diameter of the solid head of a brand new case. Fire it, measure the same spot again. If the solid head is showing anything more than slight enlargement, the pressure is too high - high enough that it is causing the solid brass to flow.
 
Your obviosly approcahing it from a target shooting perspective given the bullets your listing, and if that indeed is the case, use your chrony, stick with the most accurate load, then determine your come ups for the various distances.
A few feet per second, is'nt gonna amount to a hill of beans. Go for accuracy first and if it's 100fps slower than expected, or wanted well that's the hand your delt. Do the math write it down and practice with it.
 
tiriaq said:
The program and what you read cannot address any variables resulting from your equipment. May be reasonably accurate guesstimates, but I don't think that you should expect any better, or place absolute faith in them. Rather than depending on primer appearance, bolt lift, etc, use a good micrometer (not a caliper) to measure the diameter of the solid head of a brand new case. Fire it, measure the same spot again. If the solid head is showing anything more than slight enlargement, the pressure is too high - high enough that it is causing the solid brass to flow.
Click to expand...
thats an excellent idea, I'll look into getting one of those, thanks for the tip.
 
Lefty #### said:
Your obviosly approcahing it from a target shooting perspective given the bullets your listing, and if that indeed is the case, use your chrony, stick with the most accurate load, then determine your come ups for the various distances.
A few feet per second, is'nt gonna amount to a hill of beans. Go for accuracy first and if it's 100fps slower than expected, or wanted well that's the hand your delt. Do the math write it down and practice with it.
Click to expand...
Ive been keeping logs of all my reloading, and its interesting to compare to quickload, on general my results have been slightly lower then what the computer estimates, im still impressed with how close they are though. but as tiriaq stated, its variations in my hardware that are allways going to make the difference, the software cant account for everything.
 
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