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Posted: 5/19/2004 1:58:02 PM EDT
[Last Edit: 1/25/2006 5:53:30 PM EDT by MaverickMkii]
Hello folks.

I was fiddling with ballistics calculator and I just wanted to condense the M16/16" AR15/M4 fragmentation range data that I've gathered by reading AR15.com forums in past 2 years. Most of the MV came from manufacturers and distributors. For the ones I could not find, I estimated the number based on other people's experiments, so it should be close enough.

This is just a quick reference intended to give you a general idea of what you should expect. I ignored all the minor details. Also, I only listed the ammunition I'm interested in.


The sheet has three columns; M16 (20" barrel), 16" (16" barrel) and finally M4 (14.5" barrel).








Notes:

1.All MVs are now confirmed except: all of 75gr MV, 20" & 16" 68gr MV ETA: Q3131A and BH 75gr's MV for M4 barrel

2.Q3131A's BC is from Winchester's LE catalog. They listed MV from 24" barrel, so I took some off. ETA: It appears the MV is for 20" barrel.

3.All ammunition is zeroed at 50 yards.

4.Assumed no wind drift.

5.Used information (eg. BC of M193 and M855, etc) from MD/PA AR15 shooter's site.

6.Mk262's MV and BC confirmed, thanks to Brouhaha

7.BH 68gr OTM MV from 14.5" barrel confirmed, thanks to Kreutzberg

8.M193,M855 MV are from Bushmaster website

9.Thanks to all the "usual suspects" for helping me compile this chart
Link Posted: 5/19/2004 2:08:58 PM EDT
Great info. I just happened to test the 68gr. load today from my M4. Your velocity for the 68 gr. OTM estimate agrees very well with my experimental average of 2672, which could be slighly higher because I was testing today when it was 90 degrees here in phoenix (see my post, Test Results: BH 68 gr. OTM from 14.5 inch BBL).
Link Posted: 5/19/2004 2:18:35 PM EDT
MMKII,

That great stuff! If you get a chance it would be nie to see the same data for a 16" barrels!
Link Posted: 5/19/2004 2:18:44 PM EDT
MMKII,

That great stuff! If you get a chance it would be nice to see the same data for a 16" barrels!
Link Posted: 5/19/2004 3:25:53 PM EDT
Link Posted: 5/19/2004 3:45:03 PM EDT
[Last Edit: 5/19/2004 4:11:55 PM EDT by MaverickMkii]
Updated with 16" info and corrected 77gr Nosler's BC to .340 (thanks to brouhaha)


BTW, editing this in word is a royal PITA. I will use excel next time
Link Posted: 5/19/2004 10:21:14 PM EDT
[Last Edit: 5/19/2004 10:22:58 PM EDT by Troy]
Link Posted: 5/20/2004 4:55:58 PM EDT
Isn't a BC of .355 for the 68 gr. Hornady just a little optimistic? Seeing as how Sierra lists their 69 gr. @.305.
Link Posted: 5/20/2004 9:06:14 PM EDT
[Last Edit: 5/20/2004 9:19:02 PM EDT by MaverickMkii]
Updated again with more "realistic/reliable" fragmentation threshold. Thanks to Troy and Brouhaha again. Also recalculated the whole list using correct BC (had minor error there before)

Also, IIRC BC of BH 68gr is indeed .355.

(and yes I have verified the chart for 75 gr again and again since I thought the difference between 16" and M4 is way too big... but it turns out that way. If someone is going to use 75gr extensively he'd better make sure he gets 16" instead of 14.5")
Link Posted: 5/21/2004 5:26:05 AM EDT
Also, IIRC BC of BH 68gr is indeed .355.

So; the BC of the 77 gr. Nosler is 0.340, the 69 gr. Sierra MK is 0.305, and the BC of the 68 gr. hornady is 0.355?

I'm not trying to be a smarty-pants here but something just ain't right unless Hornady is using rocket-boosted bullets.

Anybody know where to get reliable BC's for Hornady?

SD
Link Posted: 5/21/2004 6:42:48 AM EDT
[Last Edit: 5/21/2004 6:47:58 AM EDT by MaverickMkii]
Edit : Found a website listing all hornady .22 caliber BC membres.lycos.fr/shooter/rechargt/bullets.htm

Look at 75gr A-MAX! BC of .435!


(I will correct the BC of BH 75gr to .393 when I get back)
Link Posted: 5/21/2004 7:09:48 AM EDT
The 68's BC is so high because it is a boat-tail bullet, so it's longer than I more orthodox bullet of the same weight. (I think...)
Link Posted: 5/21/2004 7:54:20 AM EDT
Link Posted: 5/21/2004 8:00:28 AM EDT
Hey! You forgot the LeMas Super Ninja Killer Round!
Link Posted: 5/21/2004 9:16:43 AM EDT
[Last Edit: 5/21/2004 9:17:13 AM EDT by Cato]
Thanks a lot!!
Ballistically speaking, how close is the Black Hills 75gr. OTM to the Hornady 75gr. TAP??
Link Posted: 5/21/2004 10:37:44 AM EDT

Originally Posted By Cato:
Thanks a lot!!
Ballistically speaking, how close is the Black Hills 75gr. OTM to the Hornady 75gr. TAP??



I think I saw somewhere that these two loadings use same bullet and Hornady 75gr is loaded a little bit hotter.
Link Posted: 5/21/2004 1:09:57 PM EDT
Updated with correct BH 75gr BC (.393 instead of .395)

Also, used more reliable fragmentation thresholds (thanks to Troy) for OTMs.
Link Posted: 5/21/2004 8:07:46 PM EDT
Very nice work, thanks for posting.

BC's are voodoo. Each mfg publishes what they want, and they may be true for the conditions they tested in, but there are many variables. Drag model, bbl twist, temp/altitude, you name it. If you want to figure out your BC, buy a chrono. Shoot a bunch of rounds near the muzzle and chrono the velocities. Using same load, move chrono out to 200 yds. Shoot again through the skyscreens (careful, careful, careful). Record those velociites. Then use a manual or ballistics program to calculate the BC for that bullet in your barrel based on the velocity loss. Otherwise, just just shoot and practice and don't worry.
Link Posted: 5/21/2004 8:14:23 PM EDT
Link Posted: 5/21/2004 8:20:59 PM EDT
Link Posted: 5/22/2004 4:15:28 AM EDT
Great work, thanks for adding the 16" data!
Link Posted: 5/22/2004 8:23:00 AM EDT
Maverick:

Just fantastic information....we all really appreciate it. The presentation format was concise, and easy to read. Don't blame you for going to "spreadsheet" form the next round!

Kudos to you!!
Link Posted: 5/22/2004 8:34:30 AM EDT

Originally Posted By Troy:
And the 75/77gr ammo's threshold is more like 2300 fps.



Cool! Thanks for that info, Troy; I was a little insecure about the 77gr loads I was making.

Thanks for putting the chart together, Maverick!
Link Posted: 5/22/2004 11:17:24 AM EDT
BHH: Thanks for filling in the details on the 69 SMK which I wasn't dilligent enough to specify. Is there a course on authoring concise and complete website posts that I guy can take at the local community college? Seems like I, and most folks, are always taking something for granted in the reader's understanding.

Jmart is right, of course. BC's, much like decibels, are very contextual measures. I've learned to have a good amount of faith in Sierra's published numbers as, when tested on the range against the computer-predicted outcome, the results have always been very, very close.

That having been said, the notion of the Hornady 68 gr having a BC of .355 against the Sierra 69 gr. of 0.305 is simply beyond the reasonably acceptable. The claim of a 77 gr. hpbt having approximately the same BC as Sierra's 150 gr. hpbt is simply beyond the pale.

SD
Link Posted: 5/22/2004 11:16:31 PM EDT
So you mean that my FED XM193 will only fragment out to 105 yards??? I thought it was more like 150 yds, or so? I thought that's what the AMMO ORACLE stated. I gotta recheck.
Link Posted: 5/23/2004 12:12:20 AM EDT
Link Posted: 5/23/2004 9:42:06 AM EDT
[Last Edit: 5/23/2004 9:47:53 AM EDT by urbankaos04]
Tell me it isn't so, Troy! That's why I picked the 16" barrel over the 20" because I thought I wasn't losing much in the ballistics department over the 20" barrel (when using M193 spec ammo). So, it looks like 68 gr Black Hills load is the way to go when using a 16" barrel (based on cost over the 77 gr Nosler).

105 yds, huh? Wow.



Link Posted: 5/23/2004 9:55:29 AM EDT
Link Posted: 5/23/2004 10:26:03 AM EDT
[Last Edit: 5/23/2004 10:27:55 AM EDT by KevinB]
Tat,

I was going to offer to do some longer range chrono work for you - but we had a simialr incident to what you had the other day and now I have to tell a buddy I shot his chrono to bits.
Link Posted: 5/23/2004 10:43:26 AM EDT
Link Posted: 5/23/2004 11:02:12 AM EDT
Link Posted: 5/23/2004 11:14:37 AM EDT

Originally Posted By tatjana:
A few things.

First: Excellent work. May we reproduce your chart in the Ammo Oracle?

Second, BC numbers are expressed in strange ways. BCs change based on velocity. Often you will get a BC that is an average of the BCs over a wide range of velocities. I would suggest for this chart that we try to find consistent BC measures across all the ammo types. For example, if we can find the BC numbers for each ammo type that represent the average from 0-300 meters then we have a good consistent measure. Since we are mixing and matching BCs here we might be shortchanging (or overestimating) a given round's performance.

On the M193 range, the question is the velocity at which they consistently fragment. Today I'll cook up a chart with Red Green and Yellow bands. M193 will PROBABLY fragment down to around 2500. But it will MORE PROBABLY fragment above 2700.

150 meters is in the "caution" range for M193 from a 16" based on this data. Other data I have seen puts it more solidly in the "green" range. Getting consistent BC data might help here.



That is the ultimate compliment, good work!
Tat,
The GREEN YELLOW RED charts look great, they're very easy to use and understand.
Link Posted: 5/23/2004 12:44:39 PM EDT
Link Posted: 5/23/2004 1:03:09 PM EDT
[Last Edit: 5/23/2004 1:10:57 PM EDT by brouhaha]
Link Posted: 5/23/2004 1:56:02 PM EDT
[Last Edit: 5/23/2004 1:58:23 PM EDT by MaverickMkii]
Thanks for compliments folks. I really didn't do anything other than fiddling with calculator and ms word. I could do it because all of you folks made your experiments and the information public.

I originally put down the maximum frag. range but Troy reminded me of many variables that would work against the it if something went wrong. Hence the change to "reliable fragmentation range".

After using this "reliable range", I see now why there are complaints coming from M4 and M855.

Oh and yes...you 16" folks have nothing to complain. Just look at BH 75gr frag chart and see how M4 does

(oh yes and...in case my IM didn't get to you, you are welcome to reproduce this in Ammo oracle, and I thank you for that . Let me know if you would like to see any changes made beforehand)
Link Posted: 5/23/2004 7:59:09 PM EDT
Tat,

Chart rocks (maybe a wee bit bigger?)

Link Posted: 5/28/2004 6:15:02 PM EDT
Folks; we're on the very verge here of formulating the "unified field theory" of what the AR platform and combinations of the 5.56 / 223 round can really do in terms of stopping fights. Simple as it may appear on set of charts and graphs, this represents a quantum leap in terms of APPLIED, USEFUL ballistics knowledge. Think about it: if you are thinking about an X length barrel and Y ammunition; no more running all over the net and buying every available book on ballistics trying to piece together information to formulate a guess as to what range your proposed combo will be good out to. Just a simple, uniform set of charts and graphs such as Tajana whipped together.

And we're almost there. Tatjana, Brouhaha, Troy, Fackler, Roberts, et al have done all of the heavy lifting so far; getting us fragmentation speeds. Now it seems that those us who are facinated with calculations should take the next step on the path MaverickMkii started us down. That will require determining a set of relible ballistic coefficients for the various bullets out there. As jmart has made clear, there is no sense comparing Sierra's BC's to Hornady's BC's to Nosler's BC's. All you end up with is a bag of smoke and pointless disagreements. We're just going to have to experiment ourselves.

I'm ready to attempt the 69 SMK's and Hornady 68's. I Intend to try first at 200 yards. That is; my Oehler 3-window @ 10 feet from the muzzle and my PACT @ 200 yards. Backing the actual recorded velocities into my Pejsa ballistics program will yield some sort of average BC over that distance. If the results seem sane, I'll locate somebody with a long range varmint gun appropriately chambered to try at 300 yards.

I'm thinking this will require handloads as the velocity consistencies of the factory stuff, including the very good manufacturers such as Fed and BH, has never impressed me much.

My experiment will be conducted in the Phoenix area; about 1,500 feet msl and about 100deg. F. This is a density altitude of about 4,500 feet or so. It might be useful if somebody were conducting an identical experiment in the cooler climes, just for comparison.

Once we have a set of BC's we can reasonably agree on, we plug into the models Maverick and Tat built for us and voila! We have really good numerical shit. No, it won't be perfect in detrmining effective fight-stopping range as 1: ballistic jell is an imperfect predictor of real life terminal billistics and 2: the experimental results keep rolling in. But look at the very cool platform we have to plug new data in to.

Gentlemen/ladies; let's have at it.

SD
Link Posted: 5/28/2004 11:58:42 PM EDT
SD,

I've got a Dillion and access to a bunch of rounds - problem is no time till next Feb...
But in that time I should be able to buy a chrono to replac emy buddies and one for me.



Derek - if you find a force protection mod for the chrono's I am all ears
Link Posted: 5/29/2004 5:26:35 AM EDT
[Last Edit: 6/1/2004 12:15:34 PM EDT by SionapRhys]
deleted
Link Posted: 5/29/2004 6:47:48 AM EDT
I've got a Dillion and access to a bunch of rounds - problem is no time till next Feb...

Canada in February..... Well, that's gonna provide a pretty good counter-point to Phoenix in June.

Did you shoot your main chrono unit or just the screens? If you need em', I've got a butt-load of spare screens; because I'm not nearly as stupid as my momma used to tell me I was.

Best,

SD

P.S. Please tell your bro's in Patty's Party Animals thanks for the very high quality work in Stan Land. Your snipers saved a lot of asses.
Link Posted: 5/29/2004 9:02:51 AM EDT
Link Posted: 5/29/2004 6:48:15 PM EDT
I would strongly suggest the Pejsa ballistic program. It's a simple DOS-based program that will run fine under Windows ("Winders" to you guys from Texas). It's purely an external ballistics calculator; does not maintain load data or anything else. Developed by a stark, raving genius named, of all things, Dr. Pejsa; who devloped the algorythms used for the Army and Marines artillery direction system; along with the Navy's gun control systems.

It's cheap, simple, and so damned accurate in it's predictions that it's freightening. I have an aquaintance who's a pretty fair distance shooter. He's been on the US Palma team a couple of times. He was looking to find a 308 load that would actually track the Shepherd Scope BDC reticle. After a couple of hours of noodling around with the Pejsa program (starting with Sierra's published BC's) and a quick trip to the range to make sure his rifle liked the loads at 100 yards; I made up 100 rounds for him and told him to go try them at various distances with his Shepherd scope. He came back muttering something about "evil black magic, unnatural, can't be real..." and threatened to burn my house down if I didn't give him the load data. It worked so well I used the program to develop a load for my 20" SR-25 and a Sheperd BDC scope.

My point in all this blather is that I've had great luck with this program; and by great luck I mean it works in the real world.

Mi dos centavos.

SD
Link Posted: 5/29/2004 11:48:32 PM EDT
Someone should tack this.
Link Posted: 5/30/2004 4:34:57 AM EDT
Link Posted: 5/30/2004 9:19:34 AM EDT
[Last Edit: 5/30/2004 9:25:23 AM EDT by MaverickMkii]
Yay, my post on ar15.com got tacked!

Updated again, now with 25-yard interval down to 300 yards. I thought working with 25 yard interval beyond 300 yards was not very useful, at least when you look at it from fragmentation perspective (or it was an excuse because I was lazy )

Anyway, it is now easier to defer from the chart where your fragmentation envelope ends.


and..I got rid of "by MaverickMkii" on the title because people helped me a lot to make this chart (both experimental data and corrections) that I deserved no credit other than punching and typing numbers, which everybody on this board can do.
Link Posted: 5/30/2004 5:34:57 PM EDT
OK: (Pant, wheeze) I've taken the first small baby step to getting us some believable BC's.

Bullet: 69 gr. SMK. Altitude: 1,550 ft. msl. Temp: 89 deg Far. Humidity: What's that?

Average (5 rounds) Velocity @:

Muzzle (10 feet, really): 2,880 fps (SD=14.7)
50 yards: 2,741 fps (SD=18.9)
100 yards 2,618 fps (SD= 20.1)
150 yards 2,498 fps (SD=24.3)
200 yards 2,342 fps (SD=26.4)
250 yards 2,222 fps (SD=31.8)

According to my handy-dandy Pejsa ballistics program, at each 50 yard increment, this works out to BC's betwen .304 and .307. this agrees nicely with Sierra's claim of .305 for speeds between 2,800 and 2,200 fps.

I've always suspected that Sierra's advertised BC's were the most realistic as, compared to the other manufacturers, they are generally the lowest. Capitalism and marketing being what they are, one can generally be confident that the most modest claim is probably the most accurate.

Now I get back and somebody wants this done in 25 yard increments?

FUCK THAT!! I'm old. I'm tired. I 've been hoofing around the goddam fucking desert all goddam fucking day, back and forth, back and forth, lugging a goddam fucking chrongraph and range finder! I'm a vet and tomorrow's Memorial day for shit sake!

Sorry...... got a little carried away with the po, po, pitiful me schtick there.....

In any event; here is one small drop in the bucket of data we need to amass.

And MaverickMkii: Yes; you did do something very cool. Like most really nifty breakthrough's, what you came up with is so simple and so obvious in retrospect, that the rest of us are going "Now why the hell didn't I think of that".

One valuable side effect from today's romp in the goddam fucking desert: My appreciation for all the work Tatjana, BrewHarHar, and others have done to get us the frag data is way up there!

Luck to all,

SD

PS. Kevin: Is it February up there yet?
Link Posted: 5/30/2004 7:13:44 PM EDT
Barrel length? Twist rate?
Link Posted: 5/31/2004 7:03:45 AM EDT
Barrel length? Twist rate?

20", 1/9, chrome, 5.56 chamber.

I'm happy to add the info but, none of that affects the bullets ballistic coeffecients (that I'm aware of).

SD
Link Posted: 5/31/2004 7:06:01 AM EDT
Link Posted: 5/31/2004 9:06:45 AM EDT
[Last Edit: 5/31/2004 9:10:45 AM EDT by SailorDude]
Nonono, I just want to calculate the CHARTS in 25 yard/meter increments.

Oh... Thank God. If I went out and re-did all that in 25 yard increments I'd end up in the cardiac unit with a divorce lawyer standing beside my bed with papers for me to sign. I'm old. I'm tired. Well, never mind.... You've heard all that.

How on earth do you people do that all day lugging gel blocks around?

Reconsideration of prior posts: Some have suggested that, instead of shooting up the chrono at long distance, why not just chrono at the muzzle and measure bullet drop at distance? While it is mathematically true that you should be able to back-compute the BC from this data, the method has some practical limitations as an experimental application.

For instance; let us suppose that:

A: You have a really swell rifle that will hold 0.50 MOA at 300 yards.
B: Your bench, bags, etc. are absolutely perfect.
C: You are an absolutely perfect shot and that every round will depart the muzzle with the cross-hairs precisely on the center of the target. (I've never met anyone who could do this and, last time I talked to him before his death, neither had Carlos Hathcock.)
D: God has informed us that the BC of the bullet in question is in fact 0.305.

Now, that 0.50 MOA group translates into 0.75" above or below the POA at 300 yards. If you measured the one that was in fact 0.75" high, you would back-compute the BC as 0.360 instead of 0.305. Re-computing that BC into velocities at various distances would result in some overly-optimistic estimates of max frag range.

I suppose you COULD chrono each round, walk out to the target after each round and meaure where it hit, walk back, fire and chrono another round, walk back to the target.... FUCK THAT!!! I'm old. I'm tired. And even then you'd still have a bunch of real-life variables floating around loose. Now, if you could find some ammo that parted company with the muzzle at exactly the same velocity every time... (Group buy, anyone?)

So, I'm thinking we're pretty well stuck with the two-chrono method. Anybody interested in a group buy for chrono screens?

Best to all.

SD
Link Posted: 6/1/2004 12:11:38 PM EDT
[Last Edit: 6/1/2004 12:15:10 PM EDT by SionapRhys]
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