Posted: 5/18/2016 1:32:40 PM EDT
[#6]
Quote History Quoted:
Thanks for the input, but I have to disagree with some of your assumptions. First, momentum is mass x velocity, and with an increase in weight, velocity goes down. I don't know the relationship between the rates of change, but I suspect that with the +/- 10% changes in weights involved that momentum might not change that much, but probably does increase for heavier rounds by some amount. Second, most talk about bullet energy, not momentum. Kinetic energy is proportional to mass x (velocity)^2, so lighter and faster bullets generally have more energy at the muzzle, and transfer of kinetic energy is what knocks down plates. Higher momentum does causes energy to be retained longer, as velocity will fall less over distance with a heavier projectile, so at some distance the heavier bullet may retain greater energy than a lighter one. Have to do the math for specific loads and distances to see who wins.
As for cast - I'm forever jaded from a lead bullet experience I had about 25 years ago where I ended up with a severely leaded barrel after shooting a box of lead reloads...I think it might've been in a 38/357 revolver, but I don't exactly remember. What I do remember is spending 3 days and an entire bottle of Hoppes 9 getting all of the lead out of the barrel. I have shot lead out of my 45s since, however, and there is no problem at 45-type velocities. OTOH, cost for buying plated bullets is very close to hard cast lead, and you get the advantage of no lead smoke while shooting indoors (if you worry about that sort of thing). I shoot the HP only because the plating is 50% thicker than on the RN and SWC bullets (HP = 9mils) and additional cost for the HP is negligible. View Quote View All Quotes View All Quotes Quote History Quoted:
Quoted:
Conventional wisdom holds that momentum is important when knocking down steel plates and bowling pins. While "weight = momentum" is something of an oversimplification, increasing bullet weight is the easiest way to increase momentum.
Standard bullet weight in .45ACP has been 230 gr for a century. Your 1911s are designed around it.
If you're shooting enough that a penny / round makes a difference, you're shooting enough to take up casting and reloading. No need for any sort of jacket or plating (let alone a hollowpoint) in practice ammo.
230 gr. RN cast.
Thanks for the input, but I have to disagree with some of your assumptions. First, momentum is mass x velocity, and with an increase in weight, velocity goes down. I don't know the relationship between the rates of change, but I suspect that with the +/- 10% changes in weights involved that momentum might not change that much, but probably does increase for heavier rounds by some amount. Second, most talk about bullet energy, not momentum. Kinetic energy is proportional to mass x (velocity)^2, so lighter and faster bullets generally have more energy at the muzzle, and transfer of kinetic energy is what knocks down plates. Higher momentum does causes energy to be retained longer, as velocity will fall less over distance with a heavier projectile, so at some distance the heavier bullet may retain greater energy than a lighter one. Have to do the math for specific loads and distances to see who wins.
As for cast - I'm forever jaded from a lead bullet experience I had about 25 years ago where I ended up with a severely leaded barrel after shooting a box of lead reloads...I think it might've been in a 38/357 revolver, but I don't exactly remember. What I do remember is spending 3 days and an entire bottle of Hoppes 9 getting all of the lead out of the barrel. I have shot lead out of my 45s since, however, and there is no problem at 45-type velocities. OTOH, cost for buying plated bullets is very close to hard cast lead, and you get the advantage of no lead smoke while shooting indoors (if you worry about that sort of thing). I shoot the HP only because the plating is 50% thicker than on the RN and SWC bullets (HP = 9mils) and additional cost for the HP is negligible.
As noted, the emphasis on momentum and heavy bullets for knocking down plates and pins is the conventional wisdom, i.e., what has been found to work best by those who do it a lot in competition, and have done so for years. You asked, I answered; you can decide whether you believe it or not. No worries.
As to leading, it's unfortunate that you had a bad experience with undersized bullets early on. At pistol velocities, leading is caused by undersized bullets; the hardness of the alloy has little to do with it, despite the oft-repeated emphasis on "hard-cast" bullets.
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