Basic understandings?? aka miss information.

[3Ackleys]

You are WAY overthinking this. Go to a shoot, see what the winners are shooting- get that cartridge. You don't have to start from scratch, all the advanced math has been done for you.

 

[CharlieNC]

For target shooting (at what distance) momentum and energy are or little importance. You need to consider the ballistic coefficient and velocity. Quick Load and Gordon Reloader Tool calculate those parameters you questioned in including recoil and trajectories, and are reasonably accurate. Especially much more than our ability to take a swag.

 

[old_heli_logger]

my understandings are such
momentum(impulse) = mass X velocity,
more velocity means faster time to target and less drop at the target.
more push / velocity (accelerarion) in the barrel equals more velocity after it leaves the barrel. so in some sense more powder should equal more push.
now this is where it gets tricky:
smaller bullet will go faster if they have enough barrel and the powder burns fast enough.
heavier bullets will go faster because they get more push by the powder longer and they have more mass. (feel free to argue this but only partially what I am looking for.)
lets assume for this case that we want faster bullets and the ultimate goal is really fast really heavy bullets or a max of mass x velocity.
we can assume that the barrel is a fixed length, or somewhat the same.
I am attempting to understand the .270 and the .308 rounds. I have both and reload and shoot both.
the case for the .308 is smaller than the .270 so less powder.

is powder expansion rate (not defined by the specific barrel) related to burn rate or is it fixed (1grn of x powder expands 10.3 times at a faster rate than powder B that also expands 10.3 times) or maybe powder x expands to 10.3x and powder B only expands to 9.3x and takes longer) I am looking for a measure of force over time by powder. with the assumption that i can guess at the same barrel length and or bullet weight what powder will give me a higher velocity.

which brings me to the last part. the .308 has more space inside the barrel before the muzzle than the .270 so I assume I need a faster burning powder despite having more of it, to apply the same force on the .270 projectile.
but having more in a smaller space may be equal???

heres the real question: does 1gn of powder A expand to the same size as 1gn of powder B. I am looking to simplify not expand on burn rates. is it true that more powder burning longer in a smaller tube gives the same punch a less powder burning faster in a bigger tube. or is my head in a dark tunnel looking backwards.

i am currently running a test; same powder volume(full case) same bullet mass, (150) and different powder speeds. unfortunately I do not as of yet have a velocity meter so until I get one it is subjective.

some of this seems a little counter intuitive, faster powder in the .270 may be too much.
so for me the word accurate is inversely equal to the size of the group, more accurate smaller group.
best round to date was a .90 grn nosler, with imr3031 powder @200m. 3/4" group - that is one fast soag. this point may not fit my understanding. i think fast powder heavy bullet should be max impulse. but maybe fast powder light bullet equals max velocity. I look forward to hearing all about this

"more velocity after it leaves the barrel"
I'm not sure this actually takes place...

 

[searcher]

"more velocity after it leaves the barrel"
I'm not sure this actually takes place...

When I was in the Marines in Quantico back in the 80's, I was told they were working on an "accelerating" bullet. I have thought about that concept ever since - and to what level of testing and concepts they had going. Imagine a guided, self-propelled bullet........ No different than a missile - just a heck of a lot smaller.

 

[old_heli_logger]

When I was in the Marines in Quantico back in the 80's, I was told they were working on an "accelerating" bullet. I have thought about that concept ever since - and to what level of testing and concepts they had going. Imagine a guided, self-propelled bullet........ No different than a missile - just a heck of a lot smaller.

Interesting, I would think you would have to hollow out the base of the bullet and fill it with very slow burning powder...not sure how you'd keep it in place. Fun to think about...

 

[searcher]

Interesting, I would think you would have to hollow out the base of the bullet and fill it with very slow burning powder...not sure how you'd keep it in place. Fun to think about...

Yeah. It is not out of the realm of possibility to get a microchip small enough to fit in there with micro fins that slightly protrude on exit - along with some propellant. Wish I had the smarts to figure that out. Maybe start with some BIG bullets...

 

[Mark W]

You might get a better response if you used the capitol on your keyboard. Us old people need all the help we can reading a post...lol

Exactly! There is no way that I would spend the time to read that gibberish.

 

[Lefty2506]

I am deciding what precision rifle I want to pay 2k for. not very many helpful answers, why would someone waste everyone's time commenting on the punctuation, and suggestions that a post is AI, if you have nothing to add just do that.

You should have started your post with that instead of asking a question for which understanding the answer requires at least a bachelor's of science level degree in chemistry, physics, or engineering.

Not to be a stickler, but you're trying do decide on which cartridge you want, not which rifle. In regards to which cartridge to use, what are your priorities in order? Off the top of my head I can think of cost, trajectory, wind deflection, energy at the target, and recoil.

FWIW, recoil is actually the result of the exhaust gasses exiting the muzzel of the rifle. It acts much like the thrust of a rocket engine. I used to think it was the result of moving the bullet down the barrel and I was willing to die on that hill. A good friend of mine scientifically proved me wrong. I didn't dig into his methodology, but he spent several years and hundreds of thousands of $$ researching this subject for Knight Armament, and used the research to design and build a recoiless full auto 556 for them, so I took him at his word. My understanding is that you could write your name on the wall with it.

 

[6.5 forever]

You should have started your post with that instead of asking a question for which understanding the answer requires at least a bachelor's of science level degree in chemistry, physics, or engineering.

I 100% agree.

 

[6.5 forever]

I will give this post the time it deserves.
Wrong.

Exactly

 

[Lefty2506]

Yeah. It is not out of the realm of possibility to get a microchip small enough to fit in there with micro fins that slightly protrude on exit - along with some propellant. Wish I had the smarts to figure that out. Maybe start with some BIG bullets...

IIRC it has been done with grenade launchers. My guess is that high volume production isn't financially feasible to do this for a rifle system.

 

[jelenko]

why would someone waste everyone's time commenting on the punctuation

Why would you write a post with no punctuation? Do you not understand it's difficult for others to understand what you are trying to communicate?

 

[jobhopper66]

To me this all seems like alot of BS as the OP has not been on here since Tuesday afternoon. Call me skeptical but this guy just seems like a troll playing everybody.

 

[6.5 forever]

To me this all seems like alot of BS as the OP has not been on here since Tuesday afternoon. Call me skeptical but this guy just seems like a troll playing everybody.

Probably sailing naked.

 

[Jonnyofalltrades]

I have read through this entire thread.....except for the OP's posts.
I honestly can not read them.

I'm sorry, but maybe you should try punctuation and sentence/paragraph structure just a little.
It really matters.

 

[c3d4b2]

After considering the post the following line of thought needs refinement.

"more velocity means faster time to target and less drop at the target."

Time to target is the important bullet drop factor. The initial velocity and the balistic coefficient are both important factors that impact the time of flight.

You may want to center your analysis around the time of flight considering both the velocity and balistic coeficient as a starting point.