115gr vs 147gr

[Miranda]

here is one-->

[JLeeCZ]

Well, they're still cool..

[RippinSVT]

I shoot both, both in minor Bianchi Cup loads. I like the 115's in my 6" Metallic 1911 (9mm) because it cycles especially soft with the added slide mass. In my comp'd Bianchi Open gun (38SC), I like the 147's because it is less "blasty" from the comp when I'm shooting barricades and it recoils insanely soft, almost like an airsoft gun. It also puts 6 shots into .68" at 50 yards.

Mind sharing your 147 load?

Starline .38SC brass, 3.5gr of Bullseye, 147 XTP seated 1.21 with a medium taper crimp and a Federal SPP. Takes a light spring to run it in a comp'd gun. Feels like a paintball gun to shoot.

[Garmil]

Interesting thanks. What fps do you get with that?

[JLeeCZ]

About a year ago, I emailed Bayou regarding 147s for 9mm asking about different powders to try. Donnie said to be sure I gave WSF a shot with the 147. It has become my go-to bullet/powder combination for the 147 and I really like it.

Edited December 13, 2015 by JLeeCZ

[yellowfin]

I tried 115's and 124's, then went to 147 plated, and now have found my favorite so far with 147gr FP Blue Bullets and Titegroup...just like hundreds of other guys on here. It feels good, offers more accuracy than I am capable of surpassing, and they're very economical.

[RippinSVT]

Interesting thanks. What fps do you get with that?

980fps from a cut-rifled 5" Lissner tube

[Bam Bam]

You guys forgot the Drag on the bullet. Velocity at the Muzzle does not equal the Velocity at impacted. Also the energy go into deforming the bullet as it hits the Plate. All energy is conserved and momentum, they can not be thought of as separate items, they are the same coupled equations.

did i make you head hurt yet

Force balance F=ma = drag + Pressure exit + impulse over

Velocity, Momentum m*v^2

[Miranda]

not really forgotten, it is a guess of what happens supported by equations.

the drag on the bullet over a 10 yard flight is not usually considered 'significant.'

ballistics books say the loss of energy can be of note over the flight of 100 yards...

and keep in mind the concept being chased is the transfer of energy.

so what is being sought is an acceleration (or what ever you want to call it when a bullet stops or deflects) at the target.

miranda

[phecksel]

bullet hitting a steel plate is in no way an inelastic collision.

It is definitely a partially inelastic collision.

Statement was it was an inelastic collision. I would contend it's not even a partial inelastic collision.

Inelastic collision in a simplified explanation, means the the masses bond together as one, turning momentum energy into molecular bonding. Bullets bounce off steel plates. The little bit that might "stick" is not bonded, it's stuck

Where the whole 1/2mv^2 argument I presented falls apart, is after the bullet strikes the plate. As the bullet begins to deform and often breaks apart, that energy is not transferred to the plate.

[busdriver02]

The deformation is what makes it a "partial" inelastic collision, kinetic energy is not conserved as a result.

Nerdery: http://hyperphysics.phy-astr.gsu.edu/hbase/inecol.html

[motosapiens]

Why not just put up some USPSA targets at 12 to 15 yards.... load 147s to PF.... load 115s to PF... and run double taps as fast as you can...

See what the timer & targets tell you. They don't lie... and they don't really care about Quantum Physics and that MV/2V/thingy. They just do the time and record the holes. Just like they do in a real match!

yeah, all this pretend physics is interesting to argue about, but i have found 147's not only more pleasant to shoot, but also faster and more accurate to shoot. There's just less movement of the gun.

i use 3.0 gr of red dot and a coated 147, but n320 or any other fast powder also shoots nice and soft.

Edited December 16, 2015 by motosapiens

[Alaskapopo]

Hello: yes there is a difference. The 147 will have more knock down power at the same power factor as the 115's. Inertia is the factor here. Just remember some of your high school physics. The weight difference is 32 grains so you can figure out what the difference will be. If you don't want to do the math load up some of each and shoot a steel popper and see which one knocks it down faster/harder. Hope this helps. Thanks, Eric

No it won't power factor is a measure of momentum (ie inertia) Muzzle velocity times mass or in actual terms the amount of force required to bring a moving object to rest. You are thinking of muzzle energy where the equation is 1/2 the mass times the velocity squared. Simply put a 147 grain bullet at 125 power factor will knock the steel down just the same as a 115 grain bullet at a 125 power factor. The recoil difference is perceived. with the 115 being a quick snap with the 147's being a slow push. I prefer the heavies myself.

Edited December 17, 2015 by Alaskapopo

[Miranda]

almost a complete circle again.

maybe we can get a thread pun or a helical joke going.

the energy in a bullet in flight we can agree about.

we call it power factor (it is a function of the amount of energy ... available.)

it may want for accuracy.

lets pick three outcomes ...

dead center of the target. --> we could assume all energy possible will transfer to the target.

a miss that shaves a sliver off the bullet --> no energy transferred.

and then the problem...

the bullet hits and deflects.

I am pretty sure the heavier bullet will transfer more energy than the lighter bullet in this case.

miranda

[Alaskapopo]

almost a complete circle again.

maybe we can get a thread pun or a helical joke going.

the energy in a bullet in flight we can agree about.

we call it power factor (it is a function of the amount of energy ... available.)

it may want for accuracy.

lets pick three outcomes ...

dead center of the target. --> we could assume all energy possible will transfer to the target.

a miss that shaves a sliver off the bullet --> no energy transferred.

and then the problem...

the bullet hits and deflects.

I am pretty sure the heavier bullet will transfer more energy than the lighter bullet in this case.

miranda

Its not energy but rather momentum we are talking about. Power factor is not an energy measurement its a momentum measurement. Again energy is 1/2 the mass times the velocity squared. Momentum is mass times velocity. http://physics.stackexchange.com/questions/141891/kinetic-energy-vs-momentum We don't have to try to figure this out again Einstein already did.

Edited December 18, 2015 by Alaskapopo

[imeyers78]

I know this Eistein guy, he's a GM in the "Open Division", right? I kid, I kid!

thanks for the clarification, Alaskapopo.

[Hi-Power Jack]

No, Einstein is the guy who feels that this entire discussion about 115 vs 147 is All Relative ....

[Miranda]

Alaskapopo,

you may call it anything you please.

the speed and mass of the energy transfer device

are both required if you want to calculate what happens.

As far as figuring it all out goes, clearly we must...

because when some one here says 'this is the accepted calculation'

there are a few others who state 'says WHO?'

As an example, there was at least one in this thread who told me pretty clearly

that I know nothing on the subject.

I can tell you I do not want to do the math and equations.

They are boring to walk through and even more boring to read.

so I have tried to state what happens in what I hoped was

easier to understand and far less intimidating.

There comes a point where mass is required to

shift an object like a steel target.

The light hitting it does not appear to cause it to fall.

miranda

[Hi-Power Jack]

The light hitting it does not appear to cause it to fall.

I've knocked over a LOT of STEEL with a 115 gr bullet at PF 127 (Remington

Green Box, from my BHP).

[Miranda]

hi Hi-Power Jack,

yup I'll also go so far as to say it can be done with even lighter bullets.

however... there are easier ways...

miranda

[Alaskapopo]

Alaskapopo,

you may call it anything you please.

the speed and mass of the energy transfer device

are both required if you want to calculate what happens.

As far as figuring it all out goes, clearly we must...

because when some one here says 'this is the accepted calculation'

there are a few others who state 'says WHO?'

As an example, there was at least one in this thread who told me pretty clearly

that I know nothing on the subject.

I can tell you I do not want to do the math and equations.

They are boring to walk through and even more boring to read.

so I have tried to state what happens in what I hoped was

easier to understand and far less intimidating.

There comes a point where mass is required to

shift an object like a steel target.

The light hitting it does not appear to cause it to fall.

miranda

Again this has already been figured out by smarter men than us and its in the laws of physics. 125 power factor is 125 powerfactor regardless of how you got there and the steel will go down the same regardless.

Pat

[peterthefish]

Alaskapopo,

you may call it anything you please.

the speed and mass of the energy transfer device

are both required if you want to calculate what happens.

As far as figuring it all out goes, clearly we must...

because when some one here says 'this is the accepted calculation'

there are a few others who state 'says WHO?'

As an example, there was at least one in this thread who told me pretty clearly

that I know nothing on the subject.

I can tell you I do not want to do the math and equations.

They are boring to walk through and even more boring to read.

so I have tried to state what happens in what I hoped was

easier to understand and far less intimidating.

There comes a point where mass is required to

shift an object like a steel target.

The light hitting it does not appear to cause it to fall.

miranda

Miranda - energy is energy and momentum is momentum. Calling a cup of tea a cup of coffee doesn't make it so, and calling momentum energy doesn't make things easier to understand. To the contrary, making things up to make them easier (for you) to understand just confuses what should be a clear issue.

You've stated that you don't want to do the math, and shown through your statements that you don't know how.

Continuing on with the rambling doesn't make things "easier to understand" or "less intimidating" - it confuses a pretty straightforward issue.

[njl]

Think of it like this...energy is not what knocks things down. Momentum is.

230gr @850fps (.45acp factory ammo) has about the same muzzle energy as a 115gr @1200fps, both are right around 368 ft*lbs. But, the momentum is way different. 230 * 850 = 195500. 115 * 1200 = 138000. So, these have about the same muzzle energy, but anyone who's shot knock down targets or bowling pins will likely say the .45acp hits way harder.

Now a 147gr @940fps has about the same momentum (PF) as the above 115gr, but less energy (288 ft*lbs). It should knock things down just as well as the 115gr (maybe better if less energy is "wasted" in bullet deformation), while feeling like considerably less recoil. It's not going to compete well with the slightly slower 230gr bullet though for moving pins because it's got far less momentum than the 230gr.

[Miranda]

Alaskapopo,

you may call it anything you please.

the speed and mass of the energy transfer device

are both required if you want to calculate what happens.

As far as figuring it all out goes, clearly we must...

because when some one here says 'this is the accepted calculation'

there are a few others who state 'says WHO?'

As an example, there was at least one in this thread who told me pretty clearly

that I know nothing on the subject.

I can tell you I do not want to do the math and equations.

They are boring to walk through and even more boring to read.

so I have tried to state what happens in what I hoped was

easier to understand and far less intimidating.

There comes a point where mass is required to

shift an object like a steel target.

The light hitting it does not appear to cause it to fall.

miranda

Miranda - energy is energy and momentum is momentum. Calling a cup of tea a cup of coffee doesn't make it so, and calling momentum energy doesn't make things easier to understand. To the contrary, making things up to make them easier (for you) to understand just confuses what should be a clear issue.

You've stated that you don't want to do the math, and shown through your statements that you don't know how.

Continuing on with the rambling doesn't make things "easier to understand" or "less intimidating" - it confuses a pretty straightforward issue.

'tis ok. I am still willing to let you be wrong.

[peterthefish]

'tis ok. I am still willing to let you be wrong.

I'd say that's mighty big of you, but you'd have to know right from wrong to do that, so the offer rings hollow.