I look on the GS custom website and see both 270gn and 300gn .375cal FN solids.
Would like to know, does one get more penetration with 270gn going faster or 300gn going slower? assume we have a 375ruger with twist that handles those weights.
Interesting I also see a long .338-250FN, how would those things penetrate compared to say the heavier,larger dia 270gnFN.375cal?
How stable would such a long slender .338cal250FN pill be while going through an animal?
Does a simlar weight in a larger diameter thats shorter in length, offer advantage?
Does penetration & stability vary that much between say the .338cal250FN and .375cal270FN ?

Trax, from what Gerard has told me the 270's out penetrate and 300's, for a 416 the 370's (380's?) out penetrate the 400's, etc. etc. Because of the overall length and some other balistic factors that is what they have found with their penetration tests. I used the 540grain FN's (instead of the 570's in my 500) on ele and they worked just fine although my suspicions are that the 570's would have done the same on brain shots, all things relative with the same velocities which for my 500 are 2115fps. As far as the 338 and 250's compared to 270's of the 375 my choice would be the 375, again there is a certain over-all length of GS bullets that produce the best penetration.


Dirk

In the IWBB, for what it is worth,
.375/300-grain GSC FN's (at either 2500 fps or 2700 fps) will out-penetrate the .375/270-grain GSC FN's at any velocity up to 2900 fps.

That is a fact.

I think that any 1:12" twist .375 will penetrate any game better with the 300-grainers than the 270-grainers.

Confusion about this comes from those using .375-caliber rifles with 1:14" twists, like the CZ. Those may do better with 270-grainers than 300-grainers.

I certainly have had excellent results on game with 300-grain Barnes-X bullets in my .375 H&H with 1:12" twist. Those bullets are longer than a GSC .375/300-grain FN.

Gerard should not tell such guff about his .375/300-grainers.

The .416/380-grain FN is a good choice over the .416/400-grain (or 410-grain) FN in any rifle with either 14" or 16.5" twist. No guff from Gerard there.

Study these sectional densities:
.375/270-grain: .274
.375/300-grain: .305
.416/380-grain: .313
.416/400-grain: .330
.416/410-grain: .338

quote:

The .416/380-grain FN is a good choice over the .416/400-grain (or 410-grain) FN in any rifle with either 14" or 16.5" twist. No guff from Gerard there.

RIP!

Why the difference between the two calibers?

465H&H

/

quote:

Originally posted by 465H&H:

quote:

The .416/380-grain FN is a good choice over the .416/400-grain (or 410-grain) FN in any rifle with either 14" or 16.5" twist. No guff from Gerard there.

RIP!

Why the difference between the two calibers?

465H&H

The .416/380-grain at SD = .313 is well past .300. Anything more is excessively long for the monometal.
Either the 14" or 16.5" twist is adequate for that .416/380-grain bullet, but 1:12" would be better of course!

The .375/300-grain FN with .305 SD is adequate and needs the 12" twist, 14" is too slow.

It would be fun to calculate some gyro-stability factors at various velocities and twists,eh? Anyone?

quote:

Originally posted by ALF:
RIP:

Can you please explain how twist rate influences penetration of a bullet?

Alf, how many times must we beat this horse?

You know dang well that the extra spin aids the transition from air to inside the critter.

Some times the transition from air through hair and hide is not perfectly normal and the extra spin keeps it stable until shoulder-stabilized-darting-supercavitation takes over inside the critter.

quote:

Originally posted by ALF:
RIP:

Can you please explain how twist rate influences penetration of a bullet?

BECAUSE IT DOES.

Andy

/

Good God Alf! Use the search button to find the 50 previous answers to this question.

Alf,

I guess you are the only guy in the world who shoots cylindrical monolithic .30 caliber bullets.

The rest of us shoot real bullets that do better when they are stable!

Pictured 500 grain Hornady FMJ at 2,400 fps with 1-14 inch twist in a solid (3/4 inch thick pine boards).



Andy

I'm beginning to understand that these Africans are bored Tinkerers stranded in the Bush.

Great things can come of boredom - usually creativity or insanity or occassionally both.

Remember when Tom Hanks lost his Soccer Ball at sea??

I am in such a rotational spin I hope I have not lost the thrust of this thread. I use the 500g GSFN in my 458 win mag, and the 300g GSFN in my 375 H&H, both in pre64 mod 70's and I guess penetration is ok as all but one has been thru and thru's. the lone 458 recovered was from my first elephants skull after a behind the ear brain shot.

quote:

Originally posted by Bryan Chick:
I am in such a rotational spin I hope I have not lost the thrust of this thread. I use the 500g GSFN in my 458 win mag, and the 300g GSFN in my 375 H&H, both in pre64 mod 70's and I guess penetration is ok as all but one has been thru and thru's. the lone 458 recovered was from my first elephants skull after a behind the ear brain shot.

Bryan, thanks for the proof in the pudding on the .375/300gr GSC FN (SD = .305).

Maybe you ought to switch to the .458/450-grain GSC FN that has an SD = 0.306 afterall, and you can even make that one go faster than the 500-grainer. .

For Alf:
Bullets don't stop spinning once inside the 800 to 1000-fold denser-than-air medium of a game critter. Witness the petals folded back and twisted in the direction of the rifling spin on the recovered softs of any make.

Supercavitation occurs in any of the "aqueous-liquid-plastico-visco-elastico-semi-soft-solid" tissues where a temporary wound channel occurs, even to a lesser degree in bone that has some elasticity. The bullet may be in a bubble of gas with only the nose "wetted." Gyro stability may be helping inside the game too.
More than enough twist is better than barely enough twist in a hunting rifle.

/

Why wouldn't a minute amount of bone, muscle, tendon, and shit remain "vaporized", or perhaps "pulverized" or "crushed" for a better term? There does remain a cavity behind the bullet's passage and the tissue that was once there is permanently transformed.

Why wouldn't that minute amount of crushed solid be flung aside momentarily with a "supercavitatory" effect aiding bullet stability? Even gross amounts of super(temporary, stretch,...)cavitation may not contribute appreciably to direct tissue damage but can you affirm that it has NO effect on the penetration/wounding equation?

Alf is correct in defining "Supercavitation" You guy's are have a problem with the proper terminology

quote:

Originally posted by PWS:
Why wouldn't a minute amount of bone, muscle, tendon, and shit remain "vaporized", or perhaps "pulverized" or "crushed" for a better term? There does remain a cavity behind the bullet's passage and the tissue that was once there is permanently transformed.

Why wouldn't that minute amount of crushed solid be flung aside momentarily with a "supercavitatory" effect aiding bullet stability? Even gross amounts of super(temporary, stretch,...)cavitation may not contribute appreciably to direct tissue damage but can you affirm that it has NO effect on the penetration/wounding equation?

Well put.
Alf is feeling shitty about it all, eh?

Well excuse me please. Temporary wound channel is cavitation, even if not the thumb sucking precisely defined SUPERCAVITATION of Alf's FLUID MECHANICS "dynamics" 101 (that is actually a 200 level engineering course that I had once upon a time "at university").
The cavitation does involve vapor filled space as tissue is forced radially away from the path of the bullet.

Who shat in Alf's corn flakes?

hi
very intresting . does all cz and brno 375s have the same 1/14 inch twist? what about 9,3x62 with the same twist2? does 9,3x62 has problen to stabilise long heavy bullets? like 286 grain and 340 grain WL solids?
regards
yes

quote:

Originally posted by yes:
hi
very intresting . does all cz and brno 375s have the same 1/14 inch twist? what about 9,3x62 with the same twist2? does 9,3x62 has problen to stabilise long heavy bullets? like 286 grain and 340 grain WL solids?
regards
yes

CZ advertizing says they make the 9.3x62 with a 1:9.5" twist. I measured mine and it had a 1:14" twist. CZ speak with forked tongue in advertizing. I was disappointed, but it is extremely accurate with the 230-ish grain Norma factory loads, a bugholer.

I have measured several CZ .375 H&H rifles, and they are all 1:14". All other brands of factory .375-caliber rifles and custom rifles I have measured (many) are 1:12".

does 1/14 twist stabilise 300 fmj or solid monolithic bullets in 375H&H?
regards
yes

I suspect the yelping about 300-grain monometals being second-rate to 270-grainers has come about due to the 1:14" twist.

I would stick to Woodleigh, Swift and Nosler 300-grainers in the 1:14" twist. Not bad company to keep.
270-grain copper or brass monometals might be safe in a 1:14" twist.

Just my twisted point of view: 1:12" is better and allows you to use any 300-grainer to better advantage than any 270-grainer.

1:14 works but barely....

/

If the earth immediately surrounding me is functionally flat but I cannot drive far enough to fall off, does that detract from the fact that it behaves flat to a degree?

By default, when a bullet strikes tissue it strikes a complex media that is best modeled as a solid but due to that very complexity, shares some of the characteristics of fluids. I have no problem acknowledging - and recognizing the limitations of - the effect of "temporary/stretch/super/_____" cavitation anymore than I have acknowledging the fact that tissue is a "viscoelastic" solid.

Ok, which has the best/most likely stable direct path and exit stradegy;

A. 250gnFN.338cal 2700fps impact vel.
B. 270gnFN.375cal 2700fps
C. 300gnFN.375cal 2500pfs
D. US in Iraq.

Like taking the GRE

BCAD in that order...

quote:

Originally posted by ALF:
One may wonder why I am so anal on the issue of supercavities and tissues being fluids?

Just for the record, this is probably the first time the words "anal" and "supercavities" have been used in the same sentence on a hunting forum.

quote:

Originally posted by Macifej:
Like taking the GRE

BCAD in that order...

Mad Mac,
You flunked!

Correct answer is: ACBD

Jim "The Wit" Manion,
You slay me ...

Are you sure Dr. RIP-n-stein??

My WOPPR 2000 says otherwise....

I posted on the thread that Yes had started cocerning BRNO ZKK without reading this one and I answered 1 in 14 inches. But I'm with Rip as I would much more prefer a 1 in 10 or even 12 could be tolerated. Just my preference, Rodney. P.S. Macifej, I'm gonna need some more bullets!

quote:

I'm gonna need some more bullets!

Already handled check your PM's

That was fast, talk about service! Rodney.

so I'm just curious, which solids are in everyone's rifles?

Alf,

quote:

You can fire a ball, cilinder, ogival bullet into fluid and as long as boundry flow conditions are evoked that satisfy cavitation criteria a supercavity is going to form

The different shapes you mention evoke the boundary flow conditions at different speeds. Cylinder shapes will cause cavitation at lower speeds than long ogives or balls where higher speeds are required for cavitation to occur.

There is a limit to the speed that can be achieved with large caliber rifles, therefore shapes that cause cavitation at lower speeds are more desireable.

quote:

The second premise would be that the supercavity will close behind the projectile

Under the right conditions the cavity (or supercavity if you want to call it that) does not close behind the bullet.

Baxter,

I shoot the 450 grain North Fork Flat Nose (far left).



The FN had 60-64 inches penetration in elephant skull vs 32-34 inches for the RN.

Gerard,

I'm sure you have seen this many times with your FN bullets. A larger than diameter wound, most likely from a temporary cavity where the pressure of the TC exceeds the elastic strength of the bone, blood and tissue surrounding it, even in an elephant skull (pictured) with a FN solid.



Pink square is FN that missed the brain which is outlined in blue.

I was covered with a thousand tiny red dots of blood splatter when I made this shot.



You can see the large diameter or greater entrance hole from the FN solid between the eyes.

Trax, You may be interested in the following.

quote:

Posted 22 July 2008 21:32 Hide Post Post
Ok, which has the best/most likely stable direct path and exit stradegy;

A. 250gnFN.338cal 2700fps impact vel.
B. 270gnFN.375cal 2700fps
C. 300gnFN.375cal 2500pfs
D. US in Iraq.

The .338 has a 1-10 twist but a bullet with a lower SD than the 300 grain .375.

Bullet weight and SD matters with FMJ's and solids.

The 300 grain .375 will probably out penetrate the other two.

From my article on FMJ penetration in a La Grange stop box:

EFFECT OF INCREASED ROTATIONAL VELOCITY.

A faster than normal rate of twist in both .375 and .458 caliber rifles at both standard and “improved†velocity levels resulted in 3-4 more plywood boards being perforated than at standard 1-14 or 1-12 rates of twist.

Rotational velocity was not as important as increased velocity (which simultaneously increases RV). The .458 wildcats (2,400 fps) penetrated 10-12 more boards than the standard 458 Winchester. The 375 improved (2,800 fps) penetrated 6 more boards than the 375 H & H.

A very high rate of twist (1-8) resulted in a penetration gain of 4 more boards over a standard 1-12 twist in the standard velocity 375 H & H. Once a bullet has been adequately stabilized to remain point forward in the test medium, it does not appear to benefit from even more RV. For instance, the 375’s 1-8 twist did not significantly improve penetration over the .458’s 1-10 twist with bullets of similar SD.

Rotational velocity of greater than 1-10 twist may still be necessary to stabilize monometal bullets of high SD, like the 500 grain Barnes X (SD .341). The Barnes X is a spitzer HP that measures 1.63 inches long. It turned over 180 degrees even after expanding to a one inch long copper wadcutter. The 500 grain A-Square and Barnes monolithic solid RN are nearly as long as the Barnes X (>1.55 inches). These unusually long bullets may also benefit from careful design, closely coinciding the bullet’s center of gravity to it’s center of form. (A parallel sided blunt RN or truncated cone FN may be more inherently stable than a bullet with more streamlined ogive).

There does not appear to be such a thing as a “magic†velocity threshold of 2,400 fps as some observers, including LaGrange, have suggested. The 375 improved at 2,800 fps penetrated 9-10 more boards than at 2,570 fps. The 465 grain A-Square perforated 13 more boards with just a 200 fps increase of velocity from 2,467 fps to 2,563 fps.

No increase in penetration was noted using contemporary versus vintage 458 Winchester ammo. Circa 1980 Remington .458 Winchester ammo loaded with what appeared to be Hornady copper clad steel jacketed FMJ-RN actually penetrated one more board than higher velocity Federal premium ammo loaded in 2001. This may have been due to the profile of the Federal and Remington FMJ, or is normal shot to shot variation of an unstable FMJ fired from a standard 1-14 inch twist barrel.

Most bullets could be de-stabilized by an edge hit on the 12 x 12 inch boards, or an overlapping hit on previous shots.

The quicker twist bullets appeared to be more consistent than ones fired from a slower twist but not enough shots were made to verify this with absolute certainty.

The 300 grain .375 destabilized more often than the heavier bullets.

When heavier FMJ bullets did exit the side of the stop box, the ones with quicker twist did so 10-13 boards later than the standard twist. This improved consistency may be the most significant finding of the evaluation.

A 458 Winchester could have the same rotational velocity as a 450 Ackley by just using a 1-12 twist.

The 450 Ackley with standard 1-14 inch twist destabilized on one out of three shots and penetrated only 36 boards. Even in a high velocity .458, a 1-14 inch twist is not capable of consistent straight line penetration.

The 450 gr RN had 11% less penetration than a 500 gr RN.

The 400 gr RN had 23% less penetration than a 500 gr. RN

The Flat Nose had 16-23% less penetration than a comparable RN in this hard, non-aqueous test medium.

When Sectional Density and velocity are similar, .375, .416, and .458 caliber cartridges have similar penetration.. For instance, the 375 H and H with 300 gr RN (SD .305) and 450 Dakota with 450 gr RN (SD .307) at the same velocity had similar penetration (61-62 boards). The 410 gr .416 (SD .338) and 500 gr .458 (SD .341) at 2,400 fps in 1-10 twist also had identical penetration.

Andy

quote:

Originally posted by Andy: ...

A. 250gnFN.338cal 2700fps impact vel.
B. 270gnFN.375cal 2700fps
C. 300gnFN.375cal 2500pfs
D. US in Iraq.

The .338 has a 1-10 twist but a bullet with a lower SD than the 300 grain .375.
Andy[/QUOTE]

Andy, you need to make a correction.

.338/250gr bullet SD = 0.313, which is greater than the 0.305 SD of the .375/300gr bullet.

In this trio the .338 has the high mark for SD and velocity.

GRE answer is still ACBD.

Will have to get me to a different puter to see all the neato pictures.

The IWBB and real game both penalize excessive velocity with resistance that increases exponentially with velocity. Mere wood has merely constant resistance for all velocities or some nearly linear/first-order function.

A 270-grain .375 FN will never beat a 300-grain .375 FN on penetration at the usual velocities between 2000 fps and 3000 fps. If both are loaded to the same momentum, it is especially true that the 300-grainer will always win in real world or IWBB.

Velocity cannot make up for lack of SD in the real world.

quote:

Velocity cannot make up for lack of SD in the real world.

The HAL 9000 and the WOPPR 2000 agree with each other....

quote:

Velocity cannot make up for lack of SD in the real world.

Well, I thought that SD was just someone's macabre sense of humour? And nothing but a practical joke.

Warrior