anybody got info on performance on tissue/gellatin sierra says hunting and mk is a nono is the jacket to thin/thick jacket core separations would like
DATA
DATA
DATA

The bullet fragments but the hunting rounds are soft points designed to penetrate and expand and save meat.  The 69 SMK is certainly lethal but you will have lead and jacket fragments everywhere.  Go do a search on [url]www.tacticalforums.com[/url] on the subject in the terminal effects forum but please dont just start asking questions before searching for something that has already been posted.  They dont like that much there.

If you are interested in hunting something larger, such as whitetail deer, I would recommend the Winchester Supreme Power Point Plus 64 gr SP. As Dev_L points out, an expanding bullet does less damage to meat while still being effective.

If your question is geared toward smaller critters, i.e. varmint hunting, then any of the lightweight polymer tipped bullets will suffice.

For two-legged critters, the 75 gr Hornady OTM and 68/69 gr OTM loads from Black Hills and Federal are hard to beat. But first test to be sure whatever bullet weight you choose is compatible with the twist rate of your rifle. People sometimes have accuracy problems using the heavier 75 gr or heavier bullets in 1/9 twist rifles.

-Charging Handle

thanks folks. its for a 1/8 twst 4 yotes, not really concerned about 2 legged varmints.

Federal 69gr SMK MV: 2646  Pentration: 14.7"  Avg Temporary Cavity: 3.9"  Avg Recovered Diameter: .40"  Avg Recovered Length: .19"  Avg Retained Weight: 27.5  Avg Fragmentation: 60.2%

[i]Data as published in "Law Enforcement General Purpose Shoulder Fired Weapons -- The Wounding Effects of 5.56mm/.223 Carbines Compared with 12 Ga Shotguns and Pistol Caliber Weapons using 10% Ordnance Gelatin as a Tissue Simulant." by Gary K. Roberts, D.D.S."[/i]

Now thats what I'm talkin' bout Forest!!!! thanks fellas!!!

Is there any info as to what velocity/range this kind of fragmentation and penitration can be relied on?  The FAQ has a great little chart plotting barrel lenght vs frag range for m193 and m855.  A simmilar chart for 69grn otms and 75/77 grn otms would be real cool.

I could do a chart for 75 gr.  I don't have the floor fragmentation velocity for the 69gr or 77gr (though I suspect the 77gr's floor is a bit lower than the 75gr).

Forest
It would be real cool of you to do a chart for the 75s.  I would really like to know how many yards difference between 69s and 77s/75s before I go to all the trouble and expense of rebarreling to a 1 in 7.  I know you have had adequate accuracy with 75s from a 1in 9. However, if I were to go to the heavy bullets I know it would not be long untill I felt compelled to rebarrel.

Thanks
Kris

Forest,

What makes you think the 77 has a lower fragmentation floor than the 75?  I assume you mean the 77 grain Nosler, not the Sierra since the neck  before fragmenting is shorter on the Nosler.  To my knowledge the 75 grain round is longer than the 77.  Would this not make it less stable and more likely to yaw quickly and fragment?

In the end I expect the difference would be so small as to be statistically insignificant.

More of a gut feeling based on my reading and the designe of the rounds.  I'm thinking the 77 gr probably has a slightly thinner jacket (partly based on it being shorter & heavier)


Yes Sir!


You are probably right - the *performance* difference would be insignificant.

Here is a chart I made back when the 68-69 grain rounds were being discussed on [url]www.tacticalforums.com[/url].

[url]www.mcw-tech.com/hiperform/68-69GrData.htm[/url]

JCraig
[url]www.mcw-tech.com/TargetExpress[/url]

Ok here is a chart of the 75gr.  Blue line represents Hornady's published expected max performance range (based on their experimental data), the fuscia line represents the 2200fps threshold in each barrel length (again based on their published test results).

Ammo was 75gr TAP - which is pretty much the same as Black Hills 75gr OTM.

[img]http://groups.msn.com/_Secure/0XQDnAh0dInIZTQe!G1ZE2g2R5A4IZ*LgRGPJPMOt0HZyQcdnE6N3ECdigD5dw*4wDeVLocd*GTiUpunwjjawOB2TkU9d7lizuczvqQRMsOJUZVc1s9hg3n*NHI36Pg6UqAX9TCI7BNM/Hornady-75gr.jpg?dc=4675425972357797164[/img]

(if the image isn't working click here: [url]http://groups.msn.com/TheMarylandAR15ShootersSite/webpagephotosii.msnw?action=ShowPhoto&PhotoID=1004[/url])
That little note in red indicates the lowest data point comes from some comments Dr G.K. Roberts made on another forum.  Hornady says at 8.5"(and I quote)"Not recommended, bullet velocity is to low for reliable expansion and fragmentation."  (and yes that typo of 'to low' is how they have it - it should read 'too low').

MSN photo hosting really reduces the resolution of the orginal chart.  Troy if you want to post the Hi-Res version contact me and I'll e-mail it to you for hosting elsewhere.

What kind of strings were used to determine the muzzle velocity?  I have a hard time believing the 16" has the same performance as the 20" but the 24" gets much better performance.  I also think the 14.5" is a bit low too.  I have seen shot to shot variances of up to 90 fps in Black Hills ammo so you need a LONG string to accurately gauge frag range on the average.

What was the muzzle velocity of the rounds fired from those barrels to give you those figures?

DevL,
You'll have to wait till tomorrow for that data (I don't have it with me).  As noted the charts represent the data as Hornady has published it.  Thought their MV does correlate closely to what I've observed with the BH.

Value taken at 21'

MV for 8.38" was not listed
MV for 11.5" was 2361fps (1:7 twist) SD 17
MV for 14.5" was 2518fps (1:7 twist) SD 22
MV for 16"   was 2616 fps (1:9 twist) SD 11
MV for 18.25" was 2641 fps (1:7 twist)
MV for 20" was 2653 fps (1:9 twist) SD 9
MV for 20" was 2663 fps (1:7 twist) SD 28
mv for 24" was 2822 fps (1:9 twist) SD 18

The 'plateau' in the data does look suspect.  And I talked with the Hornady rep about it.  There were 2 issues brought up:
1) Varinaces in manufacturing (so the 2200fps isn't a 'hard line').
2) Spin does help these critters fragment.  The data as charted by hornady covers 1:9 and 1:7 twist rates.

Edited previous posting to reflect the numbers as Hornady published them.