quote:

Originally posted by pepsiblue:

quote:

Originally posted by sigfreund:
“Gold Dot rifle bullets are optimized to ensure expansion out of barrels down to 10" at a wide variety of velocities out to 200 yards.”

Would this also hold true for a 7.5" barrel you think?

It’s difficult to find short barrel ballistics information, but based on what I could locate and some interpolation, from a 10 inch barrel I would expect the 55 grain Gold Dot bullet to be traveling about 2280 fps at 200 yards based on a muzzle velocity of 2740 fps. Reducing the barrel length from 10 to 7.5 inches would have a significant effect on MV, perhaps as much as 300-400 fps. Even with the higher value, though, the muzzle velocity of the 55 grain GD load from 7.5" should be at least 2350 fps, and that’s faster than what it would be doing at 200 yards from 10 inches.

So, I suspect that at room-clearing distances the 55 grain Gold Dot bullet would still expand from 7.5 inches. Of course, it’s necessary to consider what “expand” means. In one YouTube video I saw about firing the 64 grain Gold Dot from a 7.5 inch barrel, the bullet expanded pretty well, but only after penetrating about 8 inches, and that’s very slow. Such testing demonstrates the fallacy of only comparing recovered bullets rather than analyzing the entire ballistics signature.

And the other thing to keep in mind about the above quote is that it refers to the 55 grain Gold Dot, not any other weights.

There is some great info in this thread. I'm gonna have to look into the fusion more but my situation fortunately allows for and in my mind requires 55gr .223. I don't need to worry too much about neighbors. What I'm more concerned about is ne'er-do-wells with effective but cheap plate armor. Solid 55gr .223 will penetrate level III plate at close-ish ranges. M855 and others that drop under 3000fps won't. I think the chances of running into someone armored is greater than hitting a neighbors place, at least in my neck of the woods.

quote:

Originally posted by thunderson:
What I'm more concerned about is ne'er-do-wells with effective but cheap plate armor. Solid 55gr .223 will penetrate level III plate at close-ish ranges. M855 and others that drop under 3000fps won't.

Interesting.

You then believe that there is a significant likelihood of an attacker’s wearing armor that can be defeated by M193 but not lower velocity ammunition and that he won’t be wearing something like level III+ or IV that would stop M193—? Do you have any information or data supporting your concerns that attackers these days are more likely to be wearing a variety of level III armor rather than something higher? The reason I ask is because the National Institute of Justice specifically recommends level IV for M855 type ammunition and in my personal testing Lake City M855 averages right at 3000 fps from a 16 inch barrel.

quote:

Originally posted by sigfreund:

...It’s difficult to find short barrel ballistics information...

This site may help, although they did not test Gold Dots.

http://www.ballisticsbytheinch.com/223rifle.html

quote:

Originally posted by sigfreund:

quote:

Originally posted by IndianaBoy:
Recoil will walk the top round out of a magazine that is coupled to the one in the magazine well.

Hmm …. Useful information that I have never seen anyone report before. Many people are enamored with coupled magazines, but now I must wonder how many ever actually shoot their rifles with that setup.

I've seen it multiple times at 3-gun matches, and experienced it myself.

Usually the round will walk partially forward, and prevent insertion of the magazine until the offending top round is stripped away. Usually after two or three tries to seat the magazine with the cartridge in the way.


It might have differing rates of occurring depending on type of magazine.

quote:

Originally posted by Sigmund:

quote:

Originally posted by sigfreund:

...It’s difficult to find short barrel ballistics information...

This site may help, although they did not test Gold Dots.

I’ve seen that site but it’s frustrating because every time I go back there I can only sit in wonder at the types of ammunition chosen for the tests: 45 and 50 grain UMC—really? I’ve never even seen those loads for sale. It would also have been nice to have all the test loads identified by manufacturer item/SKU number so we knew exactly what was involved. All that expense and effort and they couldn’t have included some more common types, especially some heavy bullet loads?

quote:

Originally posted by IndianaBoy:
I've seen it multiple times at 3-gun matches, and experienced it myself.

Thanks: Another demonstration of real world experience rather than something that seems like a good idea in theory.

quote:

Originally posted by sigfreund:

quote:

Originally posted by thunderson:
What I'm more concerned about is ne'er-do-wells with effective but cheap plate armor. Solid 55gr .223 will penetrate level III plate at close-ish ranges. M855 and others that drop under 3000fps won't.

Interesting.

You then believe that there is a significant likelihood of an attacker’s wearing armor that can be defeated by M193 but not lower velocity ammunition and that he won’t be wearing something like level III+ or IV that would stop M193—? Do you have any information or data supporting your concerns that attackers these days are more likely to be wearing a variety of level III armor rather than something higher? The reason I ask is because the National Institute of Justice specifically recommends level IV for M855 type ammunition and in my personal testing Lake City M855 averages right at 3000 fps from a 16 inch barrel.

Not exactly. I don't just believe, but know, that I am rural enough that I could use any round I own and have no fear of causing damage to anyone else's property or self. So over penetration of walls isn't a concern.

While I have not personally tried it, there are plenty of examples of m855 being defeated by level III armor and m193 not being defeated. For instance, I have seen video of AR500 being defeated by m193 but stopping multiple hits from m855.

The odds of an armored attacker are slim granted, but chances are even slimmer that they would be in III+ or IV as opposed to anything else.

So the point was, not being limited by circumstance, I don't feel the need to use something that "may" penetrate up through level III in place of something that I know will and has the added bonus of being something I regularly use.

Perhaps you know a reason why I should look at something else? Do you believe that m193 is poor enough in effectiveness that the ability to penetrate an additional level of armor is outweighed?

quote:

Originally posted by thunderson:
Perhaps you know a reason why I should look at something else? Do you believe that m193 is poor enough in effectiveness that the ability to penetrate an additional level of armor is outweighed?

No. As I’ve often said, shoot someone with any load from any AR type rifle and he will probably stop being a nuisance. I’ve also pointed out many times that every self-defense decision we make involves compromises. The best we can do is to analyze our options and choose the best. It never occurred to me that I should choose a load that’s marginal in some common ways because it might be better in the scenario that you describe, so that’s why I asked: If that scenario is more likely than I believe, I’d like to know the reasons why. Based on what you told us, however, you have answered my question.

quote:

Originally posted by szuppo:
Have you looked at the Federal Lake City 5.56mm 62 Grain MK318 MOD 0 SOST ammunition?

Designated as MK318 MOD-0 the round was designed as a barrier defeating round with superior penetration and better ballistic stability when shooting through glass, car doors and other barriers where other rounds simply bounce off. It was engineered after the Marine Corp identified issues with the M855 round. MK318 utilizes a 62 grain open tip boattail match bullet with a lead core and reverse copper jacket creating the open tip.

This is what I use.

quote:

Originally posted by thunderson:
For instance, I have seen video of AR500 being defeated by m193 but stopping multiple hits from m855.

I finally got around to looking for such videos and didn’t have much luck.

There is one that shows up over and over in searches that involves firing one round of M193 at AR500 level III armor and that clearly shows what you’re describing. Unfortunately, though, it does not show M855 being tested and, more important, the gun has a 22 inch barrel that drives the bullet at well over 3300 fps. The narrator mentions another video someplace that reportedly shows M193 being stopped by the level III armor when fired from a 16 inch barrel.

Do you have a link to the video you mention above? I’m specifically curious about the barrel length in that test. Not to keep flogging the same point, but barrel length has a significant effect on 223/5.56 velocities and velocity is the key factor in all this.

Thanks.

Careful on the Mk318. Most AR barrels out there are twisted 1:7 but there's plenty of 1:9 or slower out there, too. The Mk318 lacks gyroscopic stability in 1:9 twist barrels. Also, I'd be careful of using it inside a dwelling, since it's designed to defeat barriers.

quote:

Originally posted by parabellum:
I've long been a proponent of M193 for 16" carbines. I have some ARs which have never seen anything but Federal M193.
After many years of feeling comfortable with the wounding mechanism of the cannelured 55 grain fmj projectile, I have begun to wonder if I would be better off with some of the newer generation "tactical" projectiles, such as the Hornady TAP.

The 62 grain version of the TAP looks great, and I found some chrono results online for this round out of a 16" barrel. They clocked right at 2700 fps, which is fine, although I wonder how much more velocity I'll lose out of my pet 14.5" AR. I wouldn't mind staying with the 55 grain slugs, although a slightly heavier softpoint in the 60 to 62 grain range is appealing to me. I won't be shooting any of the very heavy stuff, which I know has its fans.

Federal Tactical Bonded looks great, too, although there is no way I'm paying 2 bucks a round for .223 ammo. The TRU stuff- I'm avoiding it, based upon comments I found online about it.

Primarily, my use would be home defense, but there is a possibility I may have to use this ammo to punch through auto glass. A crimped/staked primer is a must. Just one less thing to worry about.

Your thoughts/experience/ammo recommendation are welcome.

The problem with the M193 variants is that they can work great, or they can make a clean icepick hole through the body. Vietnam was one such proving ground for the load, and Dr. Fackler commented in several of his books that he had personally seen M193 cause these icepick holes about 25% of the time, particularly after passing through heavy clothing or a canvas magazine pouch.

There are many great .223/5.56 loads out there, and they have been working so well that the 6.8 SPC project along with many of its variants designed to replace the 5.56 is dead. Naturally, these great 5.56 loads are not going to be as cheap as military surplus M193s or M855s.

I find Dr. Robert's research into it with the Naval Special Weapons Division to be the most concrete. There are several nice loads on this link:
https://pistol-forum.com/showt...4-5-56-mm-Duty-Loads

quote:

Originally posted by sigfreund:

quote:

Originally posted by thunderson:
For instance, I have seen video of AR500 being defeated by m193 but stopping multiple hits from m855.

I finally got around to looking for such videos and didn’t have much luck.

There is one that shows up over and over in searches that involves firing one round of M193 at AR500 level III armor and that clearly shows what you’re describing. Unfortunately, though, it does not show M855 being tested and, more important, the gun has a 22 inch barrel that drives the bullet at well over 3300 fps. The narrator mentions another video someplace that reportedly shows M193 being stopped by the level III armor when fired from a 16 inch barrel.

Do you have a link to the video you mention above? I’m specifically curious about the barrel length in that test. Not to keep flogging the same point, but barrel length has a significant effect on 223/5.56 velocities and velocity is the key factor in all this.

Thanks.

I'll try to link some vids here. Just for clarification, AR500 level III is rated for 7.62 at 2800fps. Obviously it's rated slightly low, which one would expect. From what I've seen it would appear that you need to be hitting above 3100fps to penetrate AR500 level III.

This vid shows m193 fired from a 16in barrel with a 1:7 twist. Average velocity at various distances(up to 25 yards) are tested. Penetration is achieved up through 20 yards. Interestingly the first shot at 20yds did not penetrate but the m193 evidently had a deviation of around 80fps in the testing.

https://www.youtube.com/watch?v=TWk3KducJNI




This vid shows M855 being defeated by AR500. Unfortunately the vid doesn't state the barrel length but it would appear to be a 16in barrel. Unknown twist rate. The M855 does eventually penetrate but it takes more than 60 rounds to do so. Also the distance seems to be around 20 yds. M855 being slower, there is no real surprise here.

https://www.youtube.com/watch?v=d2TBoP9Aoow





Here is a vid showing M855 being defeated by AR500 Level III out of a 16in barrel at close range. The vid also shows M855A1 which is supposed to be hotter and of different construction. It has no problem penetrating at close range. Construction played a part as well I believe because it penetrated at slightly above 2900fps.

https://www.youtube.com/watch?v=e0gxeSpjdSk



There is another vid that I found interesting that I'll try to find. I didn't include it here because it involved Winchester Varmit which if I recall correctly, was a 44gr bullet traveling above 3100fps. What made the vid interesting was that several barrel lengths were tested. All penetrated, 20inch down through 14.5inch. A 11.5 inch was tested but did not penetrate, obviously dropping in velocity that simply wasn't fast enough.

This message has been edited. Last edited by: thunderson,

Here's the other vid I mentioned. The ammo is Winchester 145gr Varmit which is a JHP round. It's a good example of velocity being king here. I would have expected less of a JHP but 3200+fps really makes a difference. This is all done at very close range and I would like to see this round tested at various distances. It is a fast round. Out of a 20in barrel it exceeds 3500fps.



After the .223 testing, .308 is used to show the plate stopping what it is rated for.

Those were very informative videos. I was obviously not using the right search terms.

Thank you.

AR500 is not rated by the manufacturer for M193. Velocity is key here, so if you're close enough M193 is pretty lethal.

Third party testing has been performed with calibers up to 5.56 XM193, 7.62x54R, 30.06, 6.5 Creedmore, and .338 Lapua Magnum. Results with higher calibers may vary as they are typically over the threshold of Level III rated armor.


The full AR500 FAQ.

http://palmettostatearmory.com...content=5%3a00+Email

Just ordered this, it's a really good deal. The Speer 64gr Gold Dot was mentioned earlier in this thread, and they love it over on m4carbine too. There's a good thread detailing the terminal performance of the round.

Anyway, just wanted to share. If you figure $10/mag, the Gold Dot is $0.42/rd shipped.

quote:

Originally posted by thunderson:
What I'm more concerned about is ne'er-do-wells with effective but cheap plate armor. Solid 55gr .223 will penetrate level III plate at close-ish ranges. M855 and others that drop under 3000fps won't. I think the chances of running into someone armored is greater than hitting a neighbors place, at least in my neck of the woods.

It's worth pointing out that while run of the mill steel armor will generally stop M855 but not M193, run of the mill polyethylene armor will generally stop M193 but not M855.

Both can be level III rated plates. Level III means rated to stop 6 rounds of .308 FMJ at 2750 FPS and doesn't mean anything else. You could conceivably have a level III plate that wouldn't stop M193 OR M855.

quote:

Originally posted by IndianaBoy:

quote:

Originally posted by sigfreund:

quote:

Originally posted by IndianaBoy:
Recoil will walk the top round out of a magazine that is coupled to the one in the magazine well.

Hmm …. Useful information that I have never seen anyone report before. Many people are enamored with coupled magazines, but now I must wonder how many ever actually shoot their rifles with that setup.

I've seen it multiple times at 3-gun matches, and experienced it myself.

Usually the round will walk partially forward, and prevent insertion of the magazine until the offending top round is stripped away. Usually after two or three tries to seat the magazine with the cartridge in the way.


It might have differing rates of occurring depending on type of magazine.

This has happened to me when using Polymer mags & older metal USGI mags.
It stopped occurring on my 10.5" after I installed an ALG Single Chamber muzzle break.
But that's another can of worms for folks on here.