Author Topic: can someone explain heavy, light for caliber  (Read 1666 times)

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Offline Siskiyou

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Re: can someone explain heavy, light for caliber
« Reply #30 on: March 29, 2010, 02:34:54 PM »

I think we had the same thoughts regarding the French Lebel. 

I remember an old B&W TV spy series and one or more plots delete with the Germans stealing the secrets regarding the French Infantry rifle and cartridge.
http://en.wikipedia.org/wiki/8_mm_Lebel
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Offline Dand

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Re: can someone explain heavy, light for caliber
« Reply #31 on: March 29, 2010, 02:43:04 PM »
Maybe Sci, you are also touching on a topic that leads to the "Hatcher Formula"??

I think that's the right name but maybe some one can correct me. At any rate there is / are formulas that with a given performance expected, bore diameter, twist, etc, you can calculate the "ideal" or nearly ideal bullet weight. Add some experimentation, politics, and changing technology, warfare tactics / philosophy, and you get the history Siskyou laid out.

Current technology from ammo to weapons design and manufacture makes it much easier to deal with a much wider range of projectile weights and retain performance.

Nearly everthing can be done with more precision now, chemistry is better etc. Powder has improved tremendously since the first smokeless propellants arrived. Bullets don't foul and can be made much more uniformly now, barrels and so on.



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Offline TXSPIKE

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Re: can someone explain heavy, light for caliber
« Reply #32 on: March 29, 2010, 03:26:22 PM »
I,like AtLaw,tend to chose a bullet with a sectional density at around .250 for deer size game.This chart http://www.chuckhawks.com/rifle_SD_list.htm   will give you an idea what we are taking about.Usually the most popular bullet weights for a given caliber is around .250 on the chart.

Offline Scibaer

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Re: can someone explain heavy, light for caliber
« Reply #33 on: March 30, 2010, 02:34:17 AM »
well i think the sectional density theory is something i need to educate myself on.
 maybe, the .250 sd is some sweet spot in bullet structure ?

Offline Scibaer

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Re: can someone explain heavy, light for caliber
« Reply #34 on: March 30, 2010, 02:56:47 AM »
ok here is what i have found on SD, so far.

  Sectional density is the ratio of an object's mass to its cross-sectional area.

 It conveys the ability for an object to overcome resistance. When a projectile is in flight or impacting an object, it is the sectional density of that projectile which will determine how efficiently it can overcome the resistance to air or object. The greater the sectional density is for a projectile the greater its efficiency is and therefore ability to overcome the resistance of air and object.

that ratio can be expressed as the weight of a bullet (in pounds) divided by the square of its diameter (in inches).
 in my lymans 48th edition maunal, shows the SD of the bullets used in the reciept's in the upper corner.

Offline AtlLaw

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Re: can someone explain heavy, light for caliber
« Reply #35 on: March 30, 2010, 08:16:52 AM »
ok here is what i have found on SD, so far. ... sectional density of that projectile which will determine how efficiently it can overcome the resistance to air...

Cool!  Now, look at the SD's and bullet weights for long range target shooting and compare them to the SD's and bullet weights for normal  ::)  hunting bullets and the entire range of bullets for the same caliber.  Are their any general observations you can make?   ;D

Quote
or object.

Like a PD, Bambi, Yogi, moose or Brown Bear!   :D

New thread!  "can someone explain SD"
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Offline Scibaer

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Re: can someone explain heavy, light for caliber
« Reply #36 on: March 30, 2010, 08:55:12 AM »
i already started to do just that..
 here is what i got far. ballistic cofficient is , to put it very basically the opposite of SD and the determining factor in a bullets flight path and long range behavior. so the general observation would be: the bullet with the higher BC is more stable for/at long range.

A bullet with a high(er)  BC will travel farther than one with a low(er) BC since it will retain its velocity better as it flies downrange from the muzzle, will resist the wind better, and will “shoot flatter”

and i  found this ( bolding is mine ) ... Heavy-for-caliber pointed (spitzer) bullets with a boattail design have the high BC's, whereas lighter bullets with square tails and blunt noses have lower BCs.

In ballistics, BC is a measure of its ability to overcome air resistance in flight. It is inversely proportional to the deceleration—a high number indicates a low deceleration.

so for penetration we measure the resistance in SD and  for wind resistance we measure BC, for the bullets ability to retain velocity

Offline necchi

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Re: can someone explain heavy, light for caliber
« Reply #37 on: March 30, 2010, 10:06:49 AM »
Ya but,,,
 Some of that is based on G-1 data that's near or over 100 years old now. Others are useing G-6 even newer G-7 mathmaticl formula' that borders OCD. Suffice to say that bullet design in the last decade alone HAS become rocket science. They still need to machine bullets within a given tolerance for marketing.
 Instead of delving into ALL the data produced by manufacturers, I use it as a guide and have found a simple solution.

Buy a box of bullets and shoot'm ;D 

 That in and of itself enters the quite human aspect of the equasion that can't be provided on paper or in a program. How easy are they to handle and load? How do they preform in my gun with me shooting it?
 Or I could bolt my gun to a vise and shoot it only that way and be amazed by the results. There comes a point when all the data is only that, and practical application needs to be wittnesed first hand.
found elsewhere

Offline Scibaer

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Re: can someone explain heavy, light for caliber
« Reply #38 on: March 30, 2010, 03:50:25 PM »
a short synopsis of the G tables ( drag curve models ) that refer to the drag a bullet encounters along its flight path...

    * G1 or Ingalls (by far the most popular)
    * G2 (Aberdeen J projectile)
    * G5 (short 7.5° boat-tail, 6.19 calibers long tangent ogive)
    * G6 (flatbase, 6 calibers long secant ogive)
    * G7 (long 7.5° boat-tail, 10 calibers tangent ogive, preferred by some manufacturers for very-low-drag bullets[10])
    * G8 (flatbase, 10 calibers long secant ogive)
    * GL (blunt lead nose)
i'm looking to see if i can find the actual models. this is way outside what is needed for hunting accuracy, but i do find it interesting and a foot over my head :o

the "buy a box of bullets and shoot them" is the best advice for sure, and this technical stuff is way to much information someone would need to select a bullet for hunting or punching paper for taking out a threat.

Offline AtlLaw

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Re: can someone explain heavy, light for caliber
« Reply #39 on: March 30, 2010, 04:01:33 PM »
this technical stuff is way to much information someone would need to select a bullet for hunting or punching paper for taking out a threat.

True,  :-\  but ain't it GRAND fun!?   ;D
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Offline dpe.ahoy

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Re: can someone explain heavy, light for caliber
« Reply #40 on: March 30, 2010, 04:35:14 PM »
OK, to answer the original question, ::) (Richard I thought you would answer this way), Think of it as a bra for the caliber.  Now, if you have a 36 caliber, (now think bra), light for the caliber would be an A, heavy for the caliber would be a DD. ;)  Richard, I do believe ya be needin more sleep to miss this un. ;D  DP
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Offline AtlLaw

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Re: can someone explain heavy, light for caliber
« Reply #41 on: March 30, 2010, 04:53:23 PM »
Richard I thought you would answer this way

I should have DP...  :-\  See what happens when I take something even a little seriously?   :-[

But your analogy is perfect!   ;D  'cause even though you have the range from light for caliber (36A), to heavy for caliber (36DD), the standard/normal/optimal size will still be in the ... um... eye of the beholder!   :D

And there will always be someone who thinks the 44AA is perfect...  ::)

BA DUMP BUMP!

 
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Offline dpe.ahoy

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Re: can someone explain heavy, light for caliber
« Reply #42 on: March 30, 2010, 04:58:59 PM »
Right you are Richard!  ;D ;D ;D  DP
RIP Oct 27, 2017

Handi's:22Shot, 22LR, 2-22Mag, 22Hornet, 5-223, 2-357Max, 44 mag, 2-45LC, 7-30 Waters, 7mm-08, 280, 25-06, 30-30, 30-30AI, 444Marlin, 45-70, AND 2-38-55s, 158 Topper 22 Hornet/20ga. combo;  Levers-Marlins:Two 357's, 44 mag, 4-30-30s, RC-Glenfields 36G-30A & XLR, 3-35 Rem, M-375, 2-444P's, 444SS, 308 MX, 338Marlin MXLR, 38-55 CB, 45-70 GS, XS7 22-250 and 7mm08;  BLR's:7mm08, 358Win;  Rossi: 3-357mag, 44mag, 2-454 Casull; Winchesters: 7-30 Waters, 45Colt Trapper; Bolt actions, too many;  22's, way too many.  Who says it's an addiction?

Offline drdougrx

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Re: can someone explain heavy, light for caliber
« Reply #43 on: March 30, 2010, 04:59:58 PM »
Bra???  What the.......I gotta check this thread more often!!!!
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Offline Smokin Joe

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Re: can someone explain heavy, light for caliber
« Reply #44 on: March 30, 2010, 05:20:55 PM »
Here's how my Gramps explained it to me:

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Offline Siskiyou

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Re: can someone explain heavy, light for caliber
« Reply #45 on: March 30, 2010, 05:38:09 PM »
I think I will avoid trouble and throw rocks!

When I was a kid tossing rocks that a good throwing rock had to have the right shape.  A brick had poor flight characteristics and quickly plunged to the ground.  A nicely round stream rock of the same weight travel bit a further and was a little more accurate.

In many ways I followed the “necchi program,” In short buy a box of cartridges or bullets and give them a try.  I was fortunate that in my younger years the Western deer herds were abundant.  The bottomline is that I have never found a standard factory cartridge that is considered adequate for deer a failure, but there are some I like more than others.  The result is called, “Lessons Learn.”

Earlier I mentioned the 150-grain bullet from the 30-30 and the 150-grain bullet designed for the .303 British.  I load the 150-grain RN made by Hornady for the 30-30 it has a B.C. of .186 and the Hornady 150-grain bullet for the .303 British has a B.C. of .361.

Comparing the two bullets loaded to a muzzle velocity of 2300 fps using Sierra Infinity Six software the 150-grain Round Nose fly’s like a brick.  It quickly sheds velocity and energy when compared to the higher B.C. bullet in the .303 British.

Earlier I described the circumstances, in which I would use the Jungle Carbine chambered for the .303 British, snow on the ground and of course there is snow on the vegetation.  It makes it tough to keep a scope clear of snow.  The thick vegetation which limits the shooting distance calls for a fast action rifle.  Both fit my needs because of the short barrels.  When the weather is nicer I select the 30-30.  When it comes to accuracy out two hundred yards the Jungle Carbine does not come close to my 30-30 Marlin.  A tight shot with the 30-30 will be easier than with the JC.  

This group is from my scope sighted 30-30, the upper two bullets are 150-grain Remington factory loads and the lower two are my handloaded 150-grain Hornady loads.  I am working on loads for the .303 British to tighten up results at 100-yards.  Because of my aged eyes the iron sights on the JC will be a limiting factor, but the flip side is the bad weather advantage.



Ballistic Coefficient (B.C.) represents the ability to overcome air resistance.  



I load 165-grain bullets in the .300 Savage and the 30-06.  I have been loading Hornady, Nosler, and Remington bullets.  The flat base Hornady bullet has a B.C. of .387 and the boattail version has a B.C. of .435.

The lessons began early, but the interpolation of the data continues.  The first buck I killed with the .270 Winchester was using a factory loaded 130-grain Bronze Point which has a B.C. of .372.  The bullet hit the buck behind the shoulder and fragmentized in the chest cavity.  Heart, lungs, and liver were destroyed.  On the far side there were two or three lacerations caused by bone or bullet fragments.  Only fragments from the bullet were recovered.  #2 brother got a .270 and we continued to use the Bronze Point with the same results.  I suspect the S.D. to be .242.

Sierra says that B.C.  has little effect out two 250 yards or so.  That means that it has had little effect on most of the deer I have killed in the last fifty years.  But it is import for those beyond 250 yards.  Fred the logger use to take my brother and I out hunting all the time.  Fred killed a lot of bucks with his M760 Remington in .270 Winchester.  Fred was teaching me a lesson regarding S.D. every season, but being a youngster it took time to sink in.  Fred used the 150-grain Remington C-L on deer.  At close range the bullet did not fragment like my speedy 130-grain bullets.  It made a hole going in and another going out.  If a little tracking was needed there was a good blood trail.  The bullet has a S.D. of approximately .269, and a B.C. of .261.  Field results tell the story; it is a very effective bullet.

A very similar bullet might have stagnated the .280 Remington when it was introduced.  Remington offered a 165-grain RN C-L at about 2820 fps.   In a head to head competition with the .270 Winchester and the flag ship 130-grain load the .280 failed to attract the following it deserved.  

In the world of cup and core bullets for use in 30 caliber other than the 30-30 I like a bullet that has a B.C. greater than .400 and a S.D. at or greater than .250.  In fact I use those as minimum standards for the 270 Winchester and 7MM Remington Magnum.  

One of my favorite bullets in the .270 Winchester is the 150-grain Hornady Spire Point with a B.C. of .462 and a S.D. of 279.  All three of my rifles like it.  Unlike the 130-grain bullets I started out with this bullet exits.  I shot this buck at 32.5 yards and the 150-grain load at 2870 fps from my rifle caused a lot of damage and created an exit about 2-inches.  At the range the high S.D. was a key factor.



Does it become a tossup and how much damage the hunter is willing to except when using the same cartridge.  The bullet that fragmentizes and kills the deer with little damage to the off side, and offers a limited blood trail; Or a bullet that does a lot of damage entering and exiting?

I do not understand how they killed as many deer as they did during my Dad’s generation.  Early on I can remember Dad having an octagon barrel 32-40 around the house, with some very terrible flat point Winchester bullets.  They must have flown like a brick, but they did not set off the rounds in the magazine.  I was more impressed with the different rounds he and his buddy had for the 32-Special and the 303 Savage, Sivertips, Remington C-L, and hollow points.  Things improve years later when they bought ammunition for the 300 Savage and 308.  The bullets were more pointed.

It would have been interesting to have and record a conversation with Dad regarding the “optimum bullet’ for his rifles, the first in 1940 and the second in 1980.  I am sure he had dreams and thoughts beyond his 300 Savage, what a surprise when he gave me a new M760 Remington in 270 Winchester for a birthday.
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Offline AtlLaw

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Re: can someone explain heavy, light for caliber
« Reply #46 on: March 31, 2010, 02:27:38 AM »
Perfect Joe!   :D  A picture is worth a thousand words!   ;D

See what you started DP!?   ::)   ;D

Here's how my Gramps explained it to me:


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Offline Scibaer

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Re: can someone explain heavy, light for caliber
« Reply #47 on: March 31, 2010, 03:03:18 AM »
siskiyou said " Sierra says that B.C.  has little effect out two 250 yards or so. "
and when i read a more detailed explaination of BC, in G models, they started thier data collection at or after 300 yards.
 this seems to imply that under 300 or so yards, that BC had very little effect on a bullet ? or that air resistances effects are so slight they are not as important as bullet construction or SD is ?
 
 by the way, i'm a wee bit scared of the really tall blonde :o
there is no way i want her man hands on my junk

Offline AtlLaw

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Re: can someone explain heavy, light for caliber
« Reply #48 on: March 31, 2010, 06:54:03 AM »
Now I wrote this yesterday and never hit the post button!   ::)  It's kinda outa date now; these discussions move fast don't they!  :D  But what the heck, I spent a long time writing it!   ;D

so for penetration we measure the resistance in SD and  for wind resistance we measure BC, for the bullets ability to retain velocity

Well, yes...  :-\  no... I mean your correct... but your not ... uh, you tryin to take one aspect and make it the full Monte again... I can tell you think the BC is a constant ... Wait!  How did we go from SD to BC!?   ::)
 
New thread!  "can someone explain BC"

I've got a headache...  :-[  I need a drink...   :'(

First time since I been a member her I get involved in a discussion where I state my opinions and look what happens!   ;D
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Offline AtlLaw

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Re: can someone explain heavy, light for caliber
« Reply #49 on: March 31, 2010, 07:27:16 AM »
Ya know, I really love talkin about this stuff!  It really makes you examine your opinions, long held beliefs, etc!    ;D

this seems to imply that under 300 or so yards, that BC had very little effect on a bullet?

Well let me say that the longest shot I've taken at game in the last 35 years or so was about 175 yards.  At those ranges, when I'm looking for a hunting bullet I don't really much consider BC at all.  On the other hand, shooting Hi-Power matches it's a top priority!  Believe me, I need all the help I can get!   :(

Quote
or that air resistances effects are so slight they are not as important as bullet construction or SD is?

Gee wizz!  I don't think you should be so myopic here!  most of this stuff is closely related if not intermingled!  You seem to try to make a black and white rule for things when most of it is shades of gray!  i.e., I think bullet construction plays a part in it's BC; which has a higher BC?  A flat based or a boat tail?

If I wasn't having so much fun I'd back off here!  I hate to make posative statements...  :-\  Somebody bound to come along and show me I'm wrong sooner or later... probably sooner...  then I'll look like a ig-or-ant blowhard...  :-[  My self image would be destroyed...  I'd probably take to strong drink and loose wimmins... and it would all be your fault Scibaer!  With one post you have ruined my life!   >:(  Oh the pain... the pain...   :'(

 ;D
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Offline Scibaer

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Re: can someone explain heavy, light for caliber
« Reply #50 on: March 31, 2010, 11:18:03 AM »
i like talking about this stuff too  ;) but i like to understand what im saying lol
meaning, it may read like im trying to take on aspect of this and make it a hard and fast rule, but im not.
i'm trying to isolate them, so i can better understand them as a whole.
  lol, i dont know how we went from SD to BC then to amazon looking loose women, it what else ya got ?
and your having fun, right ? thats what its all supposed to be about , i thinks.
and believe it or not , i think i understand this SD/BC stuff bit now.
at least now i have an idea of them, and can apply that somewhat when i make a bullet selection, i know i want the bullet with the higher SD.
your right again, all this talk does make you think or rethink your past selections, bullets i mean, not the wimmins.
i dont have many long held beliefs , so i'm ok there  8)
i dont mind being told i'm wrong, i cant learn nuthin other wise, and i have had more fun with this  thread then anything else so far ;)

bear tooth bullets has a ballistic calculator , you plug in numbers and it spits out stats. i fiddled around with it some. although i'm not sure what its really telling me or what i'm learning from it, i do know that SD and BC do matter, but at hunting distances i'm not sure i will worry about them too much other then to try and pick bullets with a higher SD then i have been previously using.