The Firing Line Forums - View Single Post - reloading 308 confused on bullets, powders and load data

KillThe9Ball · February 2, 2013, 12:28 PM

Alesix,

I'm new to reloading myself and am worried about 'kabooms' also!

Regarding everything I've read, if the bullet type/style/weight are the same, most load data will be close and can be used.

I'm sure you're working-up so you should be fine. From what I've read, the main differences in pressure and velocity you'll find when using the same type of bullet (from different manufactures) will be:

1. Jacket Thickness
2. Jacket Alloy/hardness
3. Dimensions and length of your chamber/throat
4. Bore wear (applicable firearm)
5. Bullet neck tension/crimp if used
6. Case wall thickness (case volume) + Length
7. Primer type/brand
8. Barrel Length
9. Ambient Temperature (30C to 100C I have read can create 4-10% pressure difference depending upon powder type).

All of the variables above are what makes some load manuals hotter or lighter than others because of the difference in test equipment (and legal liability fears). From my understanding, the brand of the bullet is the least significant characteristic assuming all else is the same (for example, Two different 168 Gr. FMJ BT from different manufactures). Furthermore, from my understanding each company puts their own manual out basically for extra revenue even though it's not necessary. If Nosler can make you think you need a Nosler manual to load Nosler bullets, well, they can then sell you two products (the bullets and their book).

Also, keep in mind that a JHP and FMJ can have different bullet lengths which will result in different levels of case volume once seated - which will affect pressure.

I'm sure someone later today that has a little more experience will chime in on this subject. I'm certainly not an expert and hope you don't take anything I say seriously... If I'm wrong on something, or perhaps worded something wrong, I would hope to be corrected... Seriously!

Good Luck

February 2, 2013, 12:28 PM	#2
KillThe9Ball Member Join Date: January 27, 2013 Location: DFW Posts: 33	Alesix, I'm new to reloading myself and am worried about 'kabooms' also! Regarding everything I've read, if the bullet type/style/weight are the same, most load data will be close and can be used. I'm sure you're working-up so you should be fine. From what I've read, the main differences in pressure and velocity you'll find when using the same type of bullet (from different manufactures) will be: 1. Jacket Thickness 2. Jacket Alloy/hardness 3. Dimensions and length of your chamber/throat 4. Bore wear (applicable firearm) 5. Bullet neck tension/crimp if used 6. Case wall thickness (case volume) + Length 7. Primer type/brand 8. Barrel Length 9. Ambient Temperature (30C to 100C I have read can create 4-10% pressure difference depending upon powder type). All of the variables above are what makes some load manuals hotter or lighter than others because of the difference in test equipment (and legal liability fears). From my understanding, the brand of the bullet is the least significant characteristic assuming all else is the same (for example, Two different 168 Gr. FMJ BT from different manufactures). Furthermore, from my understanding each company puts their own manual out basically for extra revenue even though it's not necessary. If Nosler can make you think you need a Nosler manual to load Nosler bullets, well, they can then sell you two products (the bullets and their book). Also, keep in mind that a JHP and FMJ can have different bullet lengths which will result in different levels of case volume once seated - which will affect pressure. I'm sure someone later today that has a little more experience will chime in on this subject. I'm certainly not an expert and hope you don't take anything I say seriously... If I'm wrong on something, or perhaps worded something wrong, I would hope to be corrected... Seriously! Good Luck