You are right that the weight of the whole bullet goes up, I would say it would be with the same amount of powder. Because you see ballistic charts that say the heavier bullets are a bit slower, but they pack a harder punch than the lighter bullets.
Bullet weight and powder weight are both measured in grains but are separate weights. Since you refer to 165 and 180 grains I figure you are talking about a .30 caliber for an example. So, on the side of a box of factory ammo the weight given is for bullet weight only. Factory ammo will never list powder weight due to so many types of powder.
As far as the relation of bullet weight to powder weight, as bullet weight is increased for a given cartridge powder weight is decreased. Say for a .30-06 you use 62 gr. of H4350 for a 150 gr. bullet yet 58 gr. for a 180 gr. bullet. (Example Only). Lighter bullet, more powder, more velocity. Heavier bullet, less powder, less velocity. Why? Because you are limited by pressure. Both of these loads would produce the same pressure. If you stuffed the same powder for a 150 gr. bullet under a 180 gr. you would be risking excessive pressure.
If you ever start reloading you will see this right away in the manuals. To get a better handle on the idea, go to your local reloading supply and pick up the free manuals from the various powder makers. Or get your hands on a complete manual from one of the bullet makers. Even if you do not plan to reload these manuals will give you a better understanding of your cartridge.
Wow! That is interesting. Thanks for the info. Turns out that my buddy and I were both wrong. My buddy thought that the number on the box 180gr was referring to the amount of powder. I knew it was refering to the weight of the lead but I thought the amount of powder would remain the same.
Thanks for the info.
Tom
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I have come to understand that I really enjoy learning things the hard way.
There's a MAX amount of pressure that the bullet/primer/powder can meet, and NEVER exceed. The mfg's have to juggle things around to stay below this standard!! Changeing even the brands of primers can change the load, so everything has to be checked, and rechecked!!
Look on the box of ammo you bought, there's a lot number on it. It's usually on the flap, and it's on every box sold. That number changes every time something changes in the load they use. SO, if you buy Remington 30-06, 180 grain, every time ANYTHING changes when Rem. is loading them, that lot number also changes.
As was said above, there's many brands and burning rates of powder. Each brand and size of primer has it's own charge to do it's job, ect.. ect...
As stated earlier 165g. or 180g. only refers to the weight of the projectile. As for powder weight their is no direct relation. A 165g. bullet by the same manufacture may use a completely different powder than thier 180g. load. Also as stated earlier they load to certian pressure. Also for example not all 180g. 30-06 loads will be loaded to the same pressures. This can vary between manufacturers or different loads from the same manufacturers. For each round there is an excepted max. pressure (determined to be safe in all good conditioned guns that shoot that round) but some rounds are loaded to lower pressures. Also some are loaded to higher pressures and are called +P.
Thanks to Drilling Man and the others who posted on this subject. Very interesting stuff. I might even become a reloader in a future life when I can start shading my life more towards new hobbies as parenting and work obligations recede! A couple more questions follow:
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ORIGINAL: DM
There's a MAX amount of pressure that the bullet/primer/powder can meet, and NEVER exceed. The mfg's have to juggle things around to stay below this standard!! Changeing even the brands of primers can change the load, so everything has to be checked, and rechecked!!
Do you (or anyone else?) know how the Hornaday "light magnum" factory load works? The ballistics are obviously significantly different for a given grain of bullet - implying more force behind it. Do they just creep up closer to the maximum? If so, why don't all factory loads do this?
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Look on the box of ammo you bought, there's a lot number on it. It's usually on the flap, and it's on every box sold. That number changes every time something changes in the load they use. SO, if you buy Remington 30-06, 180 grain, every time ANYTHING changes when Rem. is loading them, that lot number also changes.
At some point early in my shooting career, I was told that those numbers referred to factory runs and, for sighting purposes, boxes with identical numbers should shoot the same. I guess this might be entirely consistent with what you're saying, but I could also read what you said to mean that, for a given number, the formula stays the same, but they could be different factory runs. Therefore, if there's any little inconsistency from one run to the next, even though the formula stays the same, the cartridges could be inconsistent.
On the other hand - I really haven't seen any significant differences among any boxes of the same factory load, say Rem 180 PSP, regardless of number, so this is question, for me is very much on the margin. But I'm curious.
Hornady and Federal each use some kind of secret voodoo powder to obtain their results without exceeding pressure limits. I can say that Hornady's 30-06 Light Magnum is not B.S. It is definitely a stouter load than what I can handload.
About powders, unless you see what can the powder comes out of you cannot tell what type it is or the composition. All you can see is physical shape difference (flake, ball, extruded,etc.). Just because two powders look alike does not mean they perform the same. Disassembling a loaded round and inspecting powder will tell you nothing unless you know exactly what type it is. Look through some reload manuals and see how many different powders there are and the differences in charge weights among them.
As far as lot numbers, same lot numbers are assembled with the same batch of components. If you find an unusually accurate factory load, you can stock up on this lot number and keep things the same. Lot numbers are more importantly for the manufacturer to isolate problems with production for recall purposes.
Do yourself a big favor if you are getting into firearms and hunting. Buy a good reloading manual such as the Speer or Nosler manual and read it through good. Nothing will give you more information on all types of ammo and components. Do this even if you don't plan to reload. Good info. All Of the major bullet makers offet a reloading manual. I like the Hornady but it come as a two book set and if you don't reload you may not wish to invest in it.
Grain Question
