Stats Shooter
New member
I have posted several bits of mostly useless info on this forum in the last couple weeks but here is something that is useful to everyone. All the experienced guys know this fact, and folks who do not know it but follow good safe fundamental handloading practices won't be adversely affected. However the ignorant (like me) and reckless (not me) could have a serious issue.
We all know that a cardinal rule of handloading is to use manuals, software, and online load data as a guide, but the load must be worked up in your rifle. Then, another rule is that you must re-work any load if you change a component such as powder, bullet, primer and brass...Or if you change the jump, and anything else I'm leaving out.
But since I have gotten Quickload I am shocked to find out some information about a cartridge I have been loading for years. The .300 win mag.
First, let me state that SAAMI volume of water in a .300 wm is 92.2 gr. In my old .300 wm hunting rifle I used to use RP brass and always had to stop well short of published max loads because I was seeing pressure signs. I also couldn't get velocities as high as the book said,or even close. Well, RP brass has a case capacity of 88.5 gr water....3 less than SAAMI.
Later on, as I have gained more experience I began checking case capacity but never did a comparison, and I never checked the Remington brass I used before which is long gone now.
I now use Norma brass in .300 wm and if Remington is a studio apartment, Norma is a mansion. Norma holds 95.5 gr water as per QL. I checked several of my own cases and found an average of 95.4.
That is an 8 grain difference in Volume!!! You see countless load recepies on the internet where people are meticulous about their jump, powder, primer etc and gloss over the case part. But this should illustrate, at least in some cartridges, how important it is.
Just a quick example, my load I have settled on is 79 gr H1000, around 2900-2910 fps. 58,204 psi. MAP is 64k
In a Remington case,all else equal, that load would hit 78,153 psi and 3031 fps.... Not good.
As I said, not knowing the pressures isn't that important, provided you rework your loads when changing components and back off when things tell you too. But this illustrates just how important that rule is. While other cartridges may not have such extreme differences like the .300 wm, even a 2-3% difference in capacity can have a dangerous difference in pressure.
Hopefully someone new to hand loading will read this and avoid a catastrophic mistake.
We all know that a cardinal rule of handloading is to use manuals, software, and online load data as a guide, but the load must be worked up in your rifle. Then, another rule is that you must re-work any load if you change a component such as powder, bullet, primer and brass...Or if you change the jump, and anything else I'm leaving out.
But since I have gotten Quickload I am shocked to find out some information about a cartridge I have been loading for years. The .300 win mag.
First, let me state that SAAMI volume of water in a .300 wm is 92.2 gr. In my old .300 wm hunting rifle I used to use RP brass and always had to stop well short of published max loads because I was seeing pressure signs. I also couldn't get velocities as high as the book said,or even close. Well, RP brass has a case capacity of 88.5 gr water....3 less than SAAMI.
Later on, as I have gained more experience I began checking case capacity but never did a comparison, and I never checked the Remington brass I used before which is long gone now.
I now use Norma brass in .300 wm and if Remington is a studio apartment, Norma is a mansion. Norma holds 95.5 gr water as per QL. I checked several of my own cases and found an average of 95.4.
That is an 8 grain difference in Volume!!! You see countless load recepies on the internet where people are meticulous about their jump, powder, primer etc and gloss over the case part. But this should illustrate, at least in some cartridges, how important it is.
Just a quick example, my load I have settled on is 79 gr H1000, around 2900-2910 fps. 58,204 psi. MAP is 64k
In a Remington case,all else equal, that load would hit 78,153 psi and 3031 fps.... Not good.
As I said, not knowing the pressures isn't that important, provided you rework your loads when changing components and back off when things tell you too. But this illustrates just how important that rule is. While other cartridges may not have such extreme differences like the .300 wm, even a 2-3% difference in capacity can have a dangerous difference in pressure.
Hopefully someone new to hand loading will read this and avoid a catastrophic mistake.
although i did understand my brain farted on what i read