Tendency of heavier bullets to boost muzzle energy

[gotboostvr]

... As for a rifle in the real world muzzle energy is almost meaningless, how often is game taken at point blank range?...

At the muzzle, and point blank range are two vastly different things.

While I'll agree, muzzle energy is mostly a marketing yardstick. In the case of a "lowly" 270 Winchester maximum point blank range is about 300 yards.

 

[Howland937]

I've read the OP like 4 times and then this

The weighty bullet spends more time in barrel thus in theory it gets more push from the propellants

Just feels backward. My understanding is the longer "dwell" time of the heavier bullet in the barrel isn't a benefit in the regard that it's receiving "more push" so much as it's a result of being a heavier bullet, which needs more effort to overcome it's rested state and accelerate. Which also contributes to higher pressures with lower charges about as much as reduced case capacity.

If the goal is keeping the bullet in the barrel longer, without using a longer barrel, a reduced load at lower pressure and ultimately lower velocity would achieve that.

 

[Bfh_auto]

No it wasn't, you don't get one without the other.

That one made me laugh.

 

[Laphroaig]

The OP's hypothetical bullet weights were too extreme to be practical for the same powder weight, but I did find an example in the Hogdgon Online data.

.223 using H4895: 69 SMK starting load of 24.0 gr. results in 2870 fps. 80 gr. SMK max. load of 24.0 gr. results in 2825 fps.

Kinetic energy works out to 1262 ft. lbs. for the 69 and 1418 ft. lbs. for the 80.

That and $4 gets you a cup of coffee at Starbucks.

 

[CraigC]

At some point, we have to stop using kinetic energy as a measure of terminal effect. It ain't.

 

[Laphroaig]

Just obliging the OP (too much spare time on my hands). Terminal effect never entered into the equation.

 

[entropy]

Your posts reveal serious and, somewhat dangerous, misunderstanding. If you are thinking about loading your own ammunition, it is vital that you do some real work to find out about the physics of guns and projectiles before you actually load anything. There are lots of good sources, both books and on line, but you really need to educate yourself carefully so you can understand the relationships between powder charges and bullet weight, and a shooting forum is not a very good place to do the kind of research you need to do because whole volumes need to be understood. No one on a forum has the time to write those volumes for you, and there are many on forums that do not actually understand internal and external ballistics well enough to be sure you are getting facts and information rather than myths and legends. Please buy some (and I mean more than one) loading manuals, or go on line to read manufacturers (bullet or powder makers have lots of good information on line) load manuals to help you understand the physics you are trying to comprehend.

Pretty much all of his posts reveal that he has started to think about trying to improve or explore ideas way too advanced for what little knowledge he has on the subject. Several of us here, in several threads, have recommended he learn at the least the very basics before wading in and trying to do things that were done many years ago, often with disastrous results. I read these because it's like gawking at an accident as you pass by. I might start responding to him again if he shows he's done his due diligence and studied the basics and understands them. This thread shows the former (somewhat) , not yet the latter.

I'm not trying to discourage you, OP, I'm trying to steer you towards some proper education on the subjects involved with firearms, and they are many.