THIS Is the Dedicated 65G Bullet I Want

[sneaky one]

ROS,.. we need to move this to a new thread- fire it up dude! Ignite the fire of these pills!

Less can be more.

[sneaky one]

stanc , I agree 100%, on our pills, yet John asked me of a tip design- these are quite cool. Bigfoot is in on this also.

Funny, I have a Bigfoot chasin after me! I may make a few solids for -fun- that can be tipped with theses longer units- for comparison sakes.

RoS , needs to move his orig post on here to a New thread- so we can fire it up.

[Variable]

Can any math whiz out there do some figuring on BC stuff?

Wiki gives some commonly used equations: http://en.m.wikipedia.org/wiki/Ballistic_coefficient


The Hornady 123 Amax has a BC of .510, and a sectional density of .252 according to their website: https://www.hornady.com/store/6.5mm-...del-LBC-Lapua/


IF you took that exact same bullet profile (identical exterior shape in every way), and only changed the weight, how would the BC change?

By knowing the answer to the BC calculation already (…510), is it possible to decipher the change in BC by only altering it's mass? I'm thinking someone who's a math whiz might be able to guestimate pretty well by using one of the BC formulas to backwards change the mass alone.

If anyone can, what would the BC be lowered to by altering it's mass to 100gr.? How about 90gr.?

We can just guess until the cows come home, but some savvy math would be pretty peachy to have.

ETA: I think Stan's guess (by comparing bullets of similar shape but different weights) is probably pretty good, but a way to do it mathematically (that a non-mathnik like me coud use) would be pretty cool.

[sneaky one]

Longer tips are cool, yet can only, mostly- be used as a single load scenario- it is only for the targets in the Ar mags.= 1 @ a time.

That cool black tip would be over AR mag length- in 6.5mm design. == Maybe 2.500. ----

Unless, a significant amount of the bullet was removed , on the frontal area to accept a cone like that, hmmmmmm, hmmmm, maybe I missed a something from this weeks beatching,,, Let's keep on this!

That's where corbin may come in handy !

[Bigfoot]

Sneaky I pmed you about this but Ill throw it out here. The nose cavity that works in a slow .308 Blackout bullet might be too large for a faster 6.5 bullet. An alternative might be the smaller nose/cavity of the 95g 6.8 TTSX. Testing will tell.

I'm not so sure we need separate threads, just a bit more civility. Either way we need to welcome Sneakys input on Hankas proposed bullet, he's in a position to explore and experiment than none of us can touch.

So... Peace, reconciliation and a little patience.

I've been a member of the many different versions of this forum for ten years. I can wait a few months for that 6.5G idealized mono bullet.

[Variable]

stanc , I agree 100%, on our pills, yet John asked me of a tip design- these are quite cool. Bigfoot is in on this also.

Funny, I have a Bigfoot chasin after me! I may make a few solids for -fun- that can be tipped with theses longer units- for comparison sakes.

RoS , needs to move his orig post on here to a New thread- so we can fire it up.

It may be because I've had the misfortune of being around too many Bureaucrats, but you guys should have project names.

John needs one too. His could be called the "Hanka Tactical-G" (or I like "Project X-Wing"), and you guys need a name as well. That would differentate between the two flavors. Two threads would work well too.

I'm pretty sure you could come up with a project name.

[stanc]

That cool black tip would be over AR mag length- in 6.5mm design. == Maybe 2.500. ----

Unless, a significant amount of the bullet was removed , on the frontal area to accept a cone like that, hmmmmmm, hmmmm, maybe I missed a something from this weeks beatching,,, Let's keep on this!

Unless I've screwed up on the math, scaling down the .308 TAC-TX bullet to .264 would result in cartridge OAL of ~2.30", so there would have to be a tiny bit of tweaking to the ogive to get 2.26" OAL.

As for fitting the .308 black tip to an existing .264 bullet, it'd require having precise, dimensioned drawings to determine OAL, or the actual polymer tip and sample bullets for cut-and-try.

I'm thinking that doing preliminary testing of Hanka's concept may require two different, 100gr, .264 bullets: one with the black tip and enlarged cavity for gel tests, and one as close as possible in shape to that of the concept picture for BC measurement. It's probably unrealistic to hope that one modified bullet would be adequate for both.

[Variable]

Longer tips are cool, yet can only, mostly- be used as a single load scenario- it is only for the targets in the Ar mags.= 1 @ a time.

That cool black tip would be over AR mag length- in 6.5mm design. == Maybe 2.500. ----

Unless, a significant amount of the bullet was removed , on the frontal area to accept a cone like that, hmmmmmm, hmmmm, maybe I missed a something from this weeks beatching,,, Let's keep on this!

That's where corbin may come in handy !

Yep, that's what we're talking about on John's bullet. By making the actual copper portion of the nose shorter and blunter (like the Barnes .300Blk Tac-TX), it allows the bullet to be at a somewhat normal length. It also allows the expansion threshold to be lowered significantly. The Barnes Tac-TX supposedly opens all the way down to 1375-1400fps.

I see bullet tips on Corbin's website (http://www.swagedies.com/mm5/merchan...gory_Code=Tips ), but I think those are aluminum? Maybe they have some other ones I'm missing though. I don't think those would allow expansion like a polymer tip would. Just guessing on that one.

[Variable]

Sneaky I pmed you about this but Ill throw it out here. The nose cavity that works in a slow .308 Blackout bullet might be too large for a faster 6.5 bullet. An alternative might be the smaller nose/cavity of the 95g 6.8 TTSX. Testing will tell.

I'm not so sure we need separate threads, just a bit more civility. Either way we need to welcome Sneakys input on Hankas proposed bullet, he's in a position to explore and experiment than none of us can touch.

So... Peace, reconciliation and a little patience.

I've been a member of the many different versions of this forum for ten years. I can wait a few months for that 6.5G idealized mono bullet.

If you want a higher BC (.400 or better), and an expansion threshold that is much lower than 2000fps, then no, this thread seems to be pretty much about that.

If you want a bullet that is different though (lower BC, conventional tip, easier to get), it would seem to be pretty much at odds with the gist of John's proposal and would seem like a different bullet to me. That's just my opinion...

[stanc]

The nose cavity that works in a slow .308 Blackout bullet might be too large for a faster 6.5 bullet. An alternative might be the smaller nose/cavity of the 95g 6.8 TTSX. Testing will tell.

I wholeheartedly agree on doing appropriate testing.

I'm not so sure we need separate threads, just a bit more civility. Either way we need to welcome Sneakys input on Hankas proposed bullet, he's in a position to explore and experiment than none of us can touch.

I'm sure Sneaky's input would be welcomed, provided it is on how to develop and evaluate Hanka's concept, rather than just saying such a design isn't needed.

I've been a member of the many different versions of this forum for ten years. I can wait a few months for that 6.5G idealized mono bullet.

Well, there is no one idealized mono bullet. Sneaky has his idea of what would be desirable for a new hunting bullet, while Variable wants a tactical projectile. Since Hanka apparently is also interested in a non-expanding, solid bullet, this thread is going to get verrrrrrrrrrry long and cumbersome if it is going to include every idea for monometal bullets.

To keep the various discussions manageable, I strongly urge a separate thread for each bullet design.

[stanc]

If you want a higher BC (.400 or better), and an expansion threshold that is much lower than 2000fps, then no, this thread seems to be pretty much about that.

If you want a bullet that is different though (lower BC, conventional tip, easier to get), it would seem to be pretty much at odds with the gist of John's proposal and would seem like a different bullet to me. That's just my opinion...

It's my opinion, too. Each really deserves its own dedicated thread.

[stanc]

...this thread is going to get verrrrrrrrrrry long and cumbersome if it is going to include every idea for monometal bullets.

To keep the various discussions manageable, I strongly urge a separate thread for each bullet design.

I just noticed this thread has already gone over 190 posts, and only a small percentage are actually relevant to the OP. Perhaps the mods should expunge all of the extraneous posts to get the thread size down?

[Variable]

Okay, my head really, REALLY, REALLY hurts now.


BC math (if I understand correctly).

The weight of the projectile in pounds multiplied by the square of the bullets diameter, then take that and multiply that by "I" (Ingalls Coefficient or "Correction Factor"), and it equals BC.

A Hornady 123gr. Amax has a mass of 0.0175714316 pounds

The square of it's diameter (.264") equals 0.069696

0.0175714316 pounds divided by 0.069696 = 0.252115352387511 (I believe that's the sectional density)


.510 divided by 0.252115352387511 = a correction factor of 2.022883553779424


So it appears the correct "Ingall's Coefficient" for the Hornady 123gr. Amax bullet shape is 2.022883553779424


Righty 'O.


Now let's change the mass....

If the identically shaped bullet weighed 100 grains instead---- .0142857167 pounds

Take .0142857167 pounds and divide by .069696 which equals = .20497183052112 (New sectional density)

.20497183052112 multiplied by the Ingall's Correction factor of 2.022883553779424 equals = .4146341449492

Head = boom. Very painful, but the answer is-----

New 100gr. bullet identical in exterior shape of Hornady 123gr. Amax would have a calculated BC of about .415 (rounded it Yo!)


That of course is just by guessing the weight would be around 100gr. if the Amax were made out of copper instead....


If I round the numbers up to a civil and far less painful realm:

123gr. = BC .510
100gr. = BC .415
90 gr. = BC .373


ETA: Frack. I forgot the grooves.... Fudge it. I quit for tonight.

[stanc]

Hee, hee, hee. Pardon me for laughing, but using my method from earlier in the week, estimated BC for your 100gr bullet figures out to 0.405, which also takes into account the drive bands.
Fast, easy, and avoids a headache, too...

[Variable]

Hee, hee, hee. Pardon me for laughing, but using my method from earlier in the week, estimated BC for your 100gr bullet figures out to 0.405, which also takes into account the drive bands.
Fast, easy, and avoids a headache, too...