So what are some good match-grade 5.56 rounds to use for precision shooting? Noveske 16" stainless barrel, 1:7 polygonal.

I'm hoping to get some specific recommendations, not just "try some 69gr..."

And when I see Remington, Winchester, PMC, and Prvi all offering 223 OTM Sierra Matchking rounds with the same weight, are they all the same or are they manufacturing their own ammo but using the same bullet?

So far, I've had good, accurate results from Black Hills 77gr OTM. But it isn't "match grade" ammo. Was wondering if there was something out there I could try that's even better?

Typically, every rifle likes different ammo.    

Best place to go would be try 3-5 proven products and see what your rifle shoots the best.

So what are some proven products then? What should I be looking at? That's what I'm asking. Only ammo I've used is Black Hills and XM193. Like I said in my OP, I'd appreciate some concrete suggestions. When I'm sitting here looking at my the inventory at my online ammo supplier and there are literally 200 different types of ammo to choose from, which ones would be a good bet to try that are considered TRUE match-grade?

See these links for specifics:

http://www.ar15.com/forums/t_3_16/500993_.html

http://www.ar15.com/forums/t_3_16/490278_.html

Black hills and hornady come to mind, I've heard good things about gorilla ammo too.....but yeah try a few and see what the gun likes if you can't hand load.

Black hills blue box shoots 1 ragged hole for me
77 gr's as well

This is what I'm talking about. Hornady makes a lot of different ammo in 223 or 556. Which ones are "match" grade?

A few months ago I purchases some Superformance Match 75gr and come to find I can't actually use it in my rifle and it's not actually "match grade." So when you say "Hornady," what are you referring to, specifically?

Asym

It will be .223 but Federal Gold Medal Match

Hornady 223 Rem 75 gr BTHP Match, 223 Rem 75 gr TAP® FPD and Black Hills Blue box 77's (the once fired case prep seems to be more consistent than the red box stuff)
I have also had shockingly good results with Privi 75's.

If you don't have 1:7 then [Nevermind, RIF] If you want to limit yourself to 69's, in which I have had good experiences with both Privi and Fiocci.  I have always thought FGMM was slightly overpriced for the accuracy you get, and I HATE trying to reload the brass.  Oddly enough, the Privi seems to be one of the best for reloading.

Try the Fiocchi 77gr HPBT Match or Hornady 75 BTHP Match. Both of these shoot well in any AR that I've tried.
Both will cost you about $1/round but that the price you pay to hit exactly what you are aiming for every time.



LINK: Fiocchi 77gr




LINK: Hornady 75gr Match HPBT

-Cody

Awesome, thanks everyone.

Also, those two links posted above were very helpful.

Seems like I will try some Fiocchi 77gr MK and some Hornady Interlock (?) 75gr BTHP.

The Black Hills 5.56mm 77 grain OTM load is a proven load.  The 10-shot group pictured below was fired from a semi-automatic AR-15 from a distance of 100 yards using the Black Hills 5.56mm 77 grain OTM load.  The group has an extreme spread of 0.98".



.....











Do you even know what that term means?



....

Like I said in my OP, I already have BH 77gr. I'm looking for some other suggestions.

I've only shot about 200 rounds of the Black Hills 77gr OTM. But I do like it. And my results are about the same as what you posted. My best group was 5 shots, 100 yards. About 0.75 MOA. But I averaged around 1.5" with 10-shot groups. I'm simply looking for other types of ammo to try as well. I was experiencing some slight pressure signs with the ammo. So until BH tests the batch I was using and reports back to me, I wanted to try some other high quality rounds. I think I know what "match" means.

To me, it means something that's been manufactured with a higher level of precision and tighter tolerances with less deviation and variation from round to round. Better quality control. That way, your shots are more consistent. Better for competition or "match" use.

A while ago some people suggested I try "Hornady 75gr". But I bought the wrong type I guess—Superformance Match—and it turns out that this ammo isn't "match" just because it says "match" on the box, and the Superformance can't be used safely in my rifle (a fact Hornady burries in fine print on their website). So that's why I'm asking about specific recommendations. I could go out and buy a bunch of random ammo to try. But that seems like an exercise in futility considering there are hundreds of types to choose from. But I will be trying some Fiocchi 77gr and the regular Hornady 75gr Match (not the Superformance).

Also, this link was pretty helpful: http://www.thetruthaboutguns.com/2011/04/foghorn/ammunition-consistency-testing-round-2-hornaday-match-and-federal-xm193f/

Unlike caliber .30 and caliber 7.62mm ammunition, there has never been a National Match standard for caliber 5.56mm/.223 Remington ammunition.  

In 1965, the caliber 7.62mm Match ammunition was standardized as M118 .  The 1965 lot of 7.62mm M118 National Match ammunition had an acceptance testing mean radius of 1.9” for 10-shot groups fired at 600 yards.  At that time, this was the smallest acceptance mean radius ever achieved for National Match ammunition since records were kept, starting in the year 1919.  Naturally, the ammunition was tested from machine-rested, bolt-actioned test barrels.  The composite target pictured below shows the twenty-seven, 10-shot acceptance groups (that’s 270 rounds!) of the 1965, M118 National Match ammunition fired from the test barrels at 600 yards.  The small circle has a diameter of 6” and the large circle has a diameter of 12”.





From American Rifleman, September 1965





From American Rifleman, August 1962.



Everything else being equal, (which of course, it seldom is) a mean radius of 1.9” at 600 yards would have a mathematical equivalent of a mean radius of 0.32” at 100 yards.  Now, 100 yards is not 600 yards, but then, a semi-automatic AR-15 is not a machine-rested, bolt-actioned test barrel either.  For this reason, I like to use the mean radius of 0.32” for 10-shot groups fired at 100 yards as the benchmark for match-grade ammunition, when fired from a semi-automatic AR-15.  

I personally prefer that my match-grade hand-loads have a mean radius “in the twos,” i.e. a mean radius of 0.2x”.  My best hand-loads fired from a semi-automatic AR-15 at 100 yards have had mean radii “in the ones,” i.e. a mean radius 0.1x”.  The 10-shot group pictured below has a mean radius of  0.138”.





....


MEAN RADIUS

Mean radius is a method of measurement of the dispersion of shot-groups that takes into account every shot in the group.  It provides a more useful analysis of the consistency of ammunition and firearms (accuracy/precision) than the commonly used method of extreme spread.

The typical method used to measure a group consists of measuring the distance between the centers of the two most outlying shots of a group.  This would be the “extreme spread” of the group.  We are essentially measuring the distance between the two worst shots  of a group.  Take a look at the two targets below.  



Most people would intuitively conclude that the second target shown is the “better” group. Measuring the two groups using the extreme spread method, we find that both groups measure 2.1”.  Once again with the typical method of measuring groups we are measuring the distance between the two worst shots of the group.  This method tells us nothing about the other eight shots in the group.  So how can we quantitatively show that the second group is better than the first?  (Yes,  we could score the groups using “X-ring” count, but this does not give us any differential information about all those shots in the X-ring.)  This is were the mean radius method comes in.  It will give us that extra information we need to better analyze our groups, rifles and ammuntion.  If I just reported the measurements of the two groups above using the extreme spread meathod, without a picture, you would assume that the two groups were very much the same.  Using the mean radius method shows that the second group is much more consistent.  It has a mean radius of 0.43” compared to 0.78” for the first group.




Mean radius as defined in Hatcher's Notebook “is the average distance of all the shots from the center of the group. It is usually about one third the group diameter (extreme spread).”

To obtain the mean radius of a shot group, measure the heights of all shots above an arbitrarily chosen horizontal line. Average these measurements. The result is the height of the center of the group above the chosen line. Then in the same way get the horizontal distance of the center from some vertical line, such as for instance, the left edge of the target. These two measurements will locate the group center.

Now measure the distance of each shot from this center. The average of these measures is the mean radius.

Once you get the hang of measuring groups using the mean radius it becomes very simple to do. While being very simple to do, it is also very time consuming. Modern software programs such as RSI Shooting Lab make determining the mean radius a snap.

The picture below is a screen snapshot from RSI Shooting Lab. The red cross is the center of the group (a little high and right of the aiming point). The long red line shows the two shots forming the extreme spread or group size. The yellow line from the red cross to one of the shots is a radius. Measure all the radii and take the average to obtain the mean radius.





Mean Radius Demonstration

Let’s say you fired a 5-shot group from 100 yards and the resulting target looks like this.  (The X-ring measures 1.5” and the 10-ring measures 3.5”.)  



The extreme spread of the group measures 2.83”, but we want to find the mean radius (or average group radius.)  In order to find the mean radius we must first find the center of the group.  By “eye-balling”  the target most people would see that the group is centered to the left of the “X-ring” and probably a little high, but we need to find the exact location of the center of the group.

Locating the Center of the Group

The first step in finding the center of the group is to find the lowest shot of the group and draw a horizontal line through the center of that shot.  



Next, find the left-most shot of the group and draw a vertical line through the center of that shot.



Now measure the distance from the horizontal line to the other four shots of the group that are above that line.  Add those numbers together and divide by the total number of shots in the group (5).



2.50” + 1.03” + 2.01” + 1.30” = 6.84”

Divide by 5 to get 1.37”.  This number is the elevation component of the center of the group.

Next we need to find the windage component  of the center of the group.  From the vertical line, measure the distance to the other four shots of the group that are to the right of the line.  Add those numbers together and again divide by the total number of shots in the group (5).



1.76” + 2.54” + 0.45” + 1.19” = 5.94”

Divide by 5 to get 1.19”  This is the windage component  of the center of the group.

Finding the windage and elevation components of the center of the group is the most difficult part of this process.  Once that is done the rest of the process is a piece of cake.

Using the windage and elevation components, locate the position on the target that is 1.37” (elevation component) above the horizontal line and 1.19” (windage component) to the right of the vertical line.  This location is the center of the group!




Determining the Mean Radius

Now that we have located the position of the center of the group, the first step in determining the mean radius is to measure the distance from the center of the group to the center of one of the shots.  This line is a single “radius”.




Now measure the distance from the center of the group to the center of each of the rest of the shots in the group.  Add the measurements of all the radii together and then divide by the total number of shots in the group (5).



0.85” + 1.35” + 1.38” + 0.84” + 1.61” = 6.03”

Divide by 5 to get 1.21”.   This is the mean radius (or average group radius) of the group!

Using the mean radius measurement to scribe a circle around the center of the group gives you a graphic representation of the mean radius.  This shows the average accuracy of all the shots in the group. This demonstrates why the mean radius is much more useful than the extreme spread in evaluating the accuracy of our rifles and ammunition.





The table below will give you an idea of the relationship between the mean radius and extreme spread.





....

IMI Razor Core. It's a clone of the 5.56 pressure MK262 round that Black Hills loads for the military.

It's available at Wideners for about $0.75/round when bought by the 500-round case.

I've also had surprisingly good luck with PRVI-Partizan .223 75gr. Match. It's available for about $0.50/round if you look around a little.

The Prvi load makes for a good "poor mans"  75 grain TAP.

....

100 Yard Accuracy Evaluation of Prvi Partizan 75 grain Match Ammunition.





The Prvi Partizan 75 grain match ammunition uses an open-tip-match bullet very similar in configuration to Hornady’s 75 grain BTHP bullet used in Hornady’s TAP line of ammunition and in Black Hills’ 75 grain MHP line of ammunition.  The Prvi Partizan (PPU) bullet has a nominal length that runs approximately 0.010” – 0.015” shorter than the Hornady bullet.  The PPU 75 grain bullet does not have a cannelure, but the case mouth on this load does have a slight collet crimp on it which puts a slight crease in the bullet.















The PPU 75 grain match load uses Boxer primed brass cases and is charged with “ball” powder.  Neither the primer nor the case mouth have sealant and the primer is not crimped.  Previous chronographing of this load through multiple barrel lengths shows it to run an average of 127 fps slower than the Black Hills 75 grain MHP load.

















I have read some statements recently that claim the PPU 75 grain bullet was designed to shoot well through 1:9” twist barrels, yet none of those making these statements have provided any scientific evidence to support this claim.  According to the Greenhill formula, the optimal twist for the PPU 75 grain bullet is 1:7.6”.  

From a 1:9” twist barrel, the PPU 75 grain match bullet has a gyroscopic stability factor (GSF) of less than 1.25 for all velocities.  It is generally accepted that a rifle bullet should have a GSF of 1.5 to 2, with 1.25 being the least acceptable GSF.  




Gyroscopc stability factor from a 1:9" twist barrel.






Gyroscopic stability factor from a 1:7.7" twist barrel.






The test-vehicle for this evaluation was an AR-15 with a 24” stainless-steel Kreiger VarMatch barrel, with a 1:7.7” twist, installed on a LaRue Tactical Stealth upper receiver. A Leupold Competition Series Scope was used for sighting. No malfunctions of any kind were experienced during testing.









Following my usual protocol for accuracy evaluation, shooting was done from a bench-rest at 100 yards.  Three 10-shot groups were obtained using the PPU 75 grain match load.  Those three groups had extreme spreads that measured:

0.66”
0.92”
1.14”

for an average extreme spread of 0.91”.



The best 10-shot group from 100 yards.






The three groups from above were overlayd on each other using RSI Shooting Lab to obtain a 30-shot composite group.  The mean radius of this composite group was 0.29”.  For comparison, this composite group is pictured below next to a composite group of the Black Hills 75 grain red box MHP load as well as a composite group of one of my handloads.









Here is a repost of some of the chronograph data for the Prvi Partizan 75 grain Match load.






.....


Prvi Partizan 75 grain Match; Velocity Update


Here's a little update on the velocity aspect of the PPU 75 grain Match load.  One can't help but wonder if Prvi Partizan has been listening to its customers.  About the only complaint anyone has had with this load is that it has a lower muzzle velocity than the Hornady or Black Hills 75 grain loads.  I recently chronographed the latest lot of the PPU 75 grain Match load that I have on hand and from a 20" Colt A2 barrel it is running approximately 117 fps faster than the original lots of this ammo that I chronographed!






....


Prvi Partizan 75 grain OTM Ballistic Gel Test Results



Thanks to the efforts of the esteemed Dr. G.K. Roberts, we now have some excellent information on the terminal ballistic properties of the Prvi Partizan 75 grain OTM load.


Privi Partizan 75 gr OTM

Velocity:  2468 fps from a 16" 1:7” twist barrel

penetration in bare ballistic gel: 12.6"

neck length:  0.8”

maximum temporary cavity: 3.2” at a depth of 4.7”

recovered diameter:  0.36”

recovered length:  0.15”

recovered weight:  30.1gr

percentage of fragmentation:  60%



The same lot of Prvi Partizan 75 grain OTM ammunition that Dr. Roberts used in testing had a nearly identical velocity when I chronographed it from a 16" Colt barrel.



atmospheric conditions:

Average temperature- 83 degrees F
Humidity - 64%
Barometric pressure – 30.04
Elevation- 960 feet above sea level[/span]

Indeed!


Hornady 75 grain 223 TAP versus 75 grain MATCH





Hornady’s 75 grain BTHP Match ammunition (part #8026) is loaded with the same 75 grain boat-tail hollow point bullet that is available from Hornady as a reloading component (part #2279).  The case mouth of the Match load has a slight taper crimp on it which puts a small crease in the bullet itself.  The Hornady 75 grain 223 TAP load (part #80265) uses the same 75 grain BTHP bullet as the Match load with the addition of a cannelure.  Unfortunately, the cannelured version of this bullet is not available (to the general public) as a reloading component.












Previous lots of both the Match and 223 TAP load have been charged with a short-cut, charcoal colored extruded powder, while the most recent lots that I have purchased (including the ones used in this test session) are charged with a greenish/yellowish colored short cut, extruded powder resembling those powders found in the Hodgdon lineup of powders.  Both loads use traditional brass cases and the caseheads from both loads are head-stamped “Hornady 223-REM” and neither load appears to have sealed nor crimped primers.  The case mouth of the 223 TAP load is crimped into the cannelure of the bullet.














previous powder





recent powder





Chronograph testing was done using an Oehler 35-P chronograph with "proof-screen" technology.  All strings of fire consisted of 10-shots each.  All velocities listed below are muzzle velocities, as calculated from the instrumental velocities using Oehler’s Ballistic Explorer software program.














Accuracy testing was performed using my 24” Krieger barreled AR-15.  Shooting was done from a bench-rest at 100 yards.  All groups were 10-shot groups.  Prior to testing the Hornady ammunition, I fired a 10-shot control group using handloaded 55 grain Sierra BlitzKings. That group had an extreme spread of 0.63”.










Starting with the Hornady 75 grain 223 TAP load, I fired five, 10-shot groups from 100 yards and used the best three groups for analysis.  Those three groups had extreme spreads that measured:

1.17”
0.87”
1.05”

for a 10-shot group grand average of 1.03”.  The three 10-shot groups were over-layed on each other using RSI Shooting Lab to form a 30-shot composite group that had a composite mean radius of 0.32”.


best 10-shot group of 75 grain 223 TAP







In the same manner described above, I obtained three 10-shot groups of the Hornady 75 grain Match load.  The extreme spreads of those groups measured:

0.89”
1.03”
1.16”

for a 10-shot group grand average of 1.03”!  Over-laying those three groups on each other using RSI Shooting Lab yielded a 30-shot composite group with a mean radius of 0.36”.



best 10-shot group of 75 grain MATCH






For additional comparison, I obtained three 10-shot groups from 100 yards using hand-loaded Hornady 75 grain BTHP bullets.  The extreme spreads of those groups measured:

0.78”
0.71”
0.52”

for a 10-shot grand average of 0.67”.  The mean radius formed from over-laying those three groups on each other was 0.23”.


best 10-shot group of hand-loaded 75 grain BTHP






Here’s a pic of the composite groups side by side for comparison.






Lastly, in a tribute to the Internet Commando, I fired two, 3-shot groups in a row from 100 yards using the control load.  Both groups were sub-QUARTER-minute-of-angle.





.....











....

Thanks for the recommendations, folks. I have a few options to look at now :)

And while all very interesting information, a how-to on measuring extreme spread and mean radius is bit off topic.

But here is my best group I got with the BH 77gr OTM @ 100 yards. Noveske Recon barrel.

I dont think that was off topic at all. Not only did he thoroughly explain what the term "match ammo" is, which you so loosely use, but Molon also gave an in depth analysis on each bramd and itteration of match ammo that he mentioned.

My comment was only referring to one of those three different topics. ;) Explaining what "match" actually means and giving an analysis of some different brands is great. Very helpful info.

And if I understand and believe what I'm reading, there is no such thing as "match" ammo when it comes to .223 or 5.56. If that's the case, then I'm using the term in its more colloquial form. For example, I doubt anybody would consider Wolf ammo to be "match grade." I was simply looking for some suggestions for high-quality ammo to try. I didn't think it would be such a controversial question...

I will look into some Fiochhi 77gr, Hornady 75gr, and some loads from Southwest Ammo and Asym.

THATs what I'm talking about - these folks that call a 1" group "match quality"...pfft - not for me it isn't.  Both my LAR-8 X-1 and Ruger 77 MKII Target (308) can print groups like that with FGMM or a good handload, but I have yet to find something that will make my LAR15 X-1 perform acceptably, though it is supposed to be capable of it.  I'm trying Privi 69gr match (not expecting much there based on 308 performance), BH 77gr, some similar velocity 77gr handloads, and Australian Outback 69gr match next time out.  I've read good things about the Australian Outback stuff, and I just bought it for just over 50 cpr, so I'm keeping my fingers crossed with that one.

Molon gave you an exact answer to your question about specific ammo, and further explained why mean radius is a more accurate way to determine "match" quality 5.56 ammo than simply average group size, which would be relevant because, as was stated, there is no "standard" for 5.56 match ammo.

Thanks Molon, I never fail to learn something from your posts.

Molon, welcome back!  I've always admired your generosity with your data.

Winning match-grade ammo in a factory box?  The USAMU shot Federal 69 GMMs for a long time and took everybody's lunch money.  They settled on Black Hills and Atlanta Arms loaded with Sierra 77s for 200, 300, and Infantry Trophy Match shooting to haul just one magazine-length ammo in the trailer.  Their coach still says the 69s had a higher X-count.

We shot HSM at the Navy Fleet Matches (both Atlantic and Pacific Fleet) and the All-Navy Matches in 1999, then Black Hills in 2001 and 2002.  Everyone shoots issued ammo only.  

The Marines issue Black Hills moly-coated MK 294 Mod 0 77-grainers.



There are LOTS of other good loads available, as Molon pointed out.  What shoots best in YOUR rifle might not be the same as that shot in a weapon built at Quantico, Crane, Benning, and a few other military shops.

Match grade and 5.56 don't go together. It's like oil and water.

Black Hills is "match grade" ammo. Not sure why you would think it isn't.

BTW, "match grade" is not a standard term in the industry. LIterally any ammunition can be "match grade"

I'd go with the 77gr TMKs.

Which BH 77gr OTM? The .223 or the 5.56? New or reloaded?

Molon happens to be one of the greats when it comes to firearms forums.  The effort he puts into actually explaining what is going on makes it so your question is answered in full.   The reason we get crap answers and run people out is that he put time into answering your question and rather than thanking him and trying to understand you act as if it is off topic because you don't understand how they are related.

Thank you Molon. That was very educational and spot on as always.

So here's an update. I went out today and shot some Hornady 75gr Match (not the superformance). Here are the results at 100 yards through a Noveske Recon, 1:7 twist stainless barrel.

Black Hills 77gr 5.56 SMK:









Hornady 75gr .223. I shot a few boxes. But this was the best group. Seems like my rifle just doesn't like it. So far out of all the ammo I've tried, Black Hills shoots the best. I'll keep looking for different brands/types to try. But I don't think I'll get my groups any smaller than 0.75 - 1.00 MOA with this gun.

Depending on your requirements to reach out you might try lighter rounds.  I have had extremely good groups at 100 yards with the 53gr superformances from hornady through the factory noveske recon I had.  

Every barrel is different but those things really shot well for me.  Back when the moa all day challenge was a big thing I put down an almost 1moa 5x5 group using those rounds with IRON SIGHTS.

Can't shoot Hornady Superformance through my rifle. Hornady themselves warn against it. Longest range I have access to is 200 yards. So I don't really have a need for super long distances. But so far 77gr is giving me the best results. Though I haven't tried anything lighter than 55gr. Won't a 1:7 twist barrel spin a light bullet too fast?

can you share the through my rifle part?  What rifle do you have that you can't shoot it and where did you see that?

I was also impressed with the 53 grain Superformance load.

From Hornady.




....

I tested about 8-10 different 75 and 77 gr loads last year and posted the results here, I'll try and dig them up.

I found none of the Hornady's shot great, but the Superformance was horrible.  The Black Hills I used wasn't all that special either.

Biggest surprise out of the group was the economical PRVI 77gr and the Nosler Match ammo.  The Nosler was simply amazing.

The factory Nosler load is good stuff for sure.




But then, so are the Black Hills loads.


100 yard Accuracy Evaluation of Black Hills 75 grain MHP:  red box versus blue box.





As previously discussed in this thread, the primary difference between Black Hills' red box and blue box ammunition lies with the brass case.  Red box ammunition uses virgin brass, while blue box ammunition uses once fired brass that has been resized.  

Both the red box and blue box 75 grain Match hollow point loads use the Hornady 75 grain BTHP bullet with a cannelure and both have crimped case necks.  Both loads are charged with “ball” powder and with the two lots of this ammunition that I chronographed the blue box load ran an average of 50 fps faster than the red box.

Accuracy testing of both loads was done from a bench-rest at 100 yards.  The test-vehicle was an AR-15 with a 24” stainless-steel Kreiger VarMatch barrel, with a 1:7.7” twist, installed on a LaRue Tactical Stealth upper receiver.  A Leupold Competition Series Scope was used for sighting.  No malfunctions of any kind were experienced during testing.









Prior to testing the Black Hills ammunition, I obtained three 10-shot groups of a control load consisting of hand-loaded Sierra 55 grain BlitzKings (at a distance of 100 yards of course.)  Those three groups had extreme spreads of:

0.537”
0.57”
0.69”

for an average extreme spread of 0.599”.

The three 10-shot groups were overlayed on each using RSI Shooting Lab to obtain a 30-shot composite group that had a mean radius of 0.19”.



Best 10-shot group of the control load.






Following the same procedures used with the control load, three 10-shot groups of the Black Hills red box 75 grain MHP fired from 100 yards were obtained.  Their extreme spreads measured:

0.96”
1.00”
1.04”

for an average extreme spread of 1.00”.

As with the control load, the three 10-shot groups from the red box ammunition were overlayed on each other to obtain a 30-shot composite group with a mean radius of 0.32”.

In the same manner as above, three 10-shot groups of the blue box 75 grain MHP were obtained from 100 yards with extreme spreads of:

1.11”
1.16”
1.16”

for an average extreme spread of 1.14”.

Those three 10-shot groups overlayed on each other had a mean radius of 0.37”.   Here are the 30-shot composite groups side-by-side for comparison.









The best 10-shot groups from the Black Hills 75 grain MHP loads.






Lastly, for the Internet Commandos in our audience, I fired a 3-shot group of the red box 75 grain MHP from 100 yards.  That group measured 0.276”.






Here’s a repost of some of the chronograph data for the Black Hills loads.

Yep, that's it. I don't know if it's effectively safe or not in the real world. But I don't want to chance it with an expensive rifle.

No.




By definition, an “unstable” bullet will have a gyroscopic stability factor of less than 1.0 at the muzzle.  A typical 55 grain FMJ bullet will have a gyroscopic stability factor of approximately 3.7 when fired from a 20” barrel with a 1:7” twist.  [CaptainObvious] 3.7 is not less than 1.0. [/CaptainObvious].


The following demonstration compares the results of firing four 10-shot groups of the same lot of 55 grain Prvi Partizan M193 ammunition from two different barrels; one barrel with a 1:9” twist, the other barrel with a 1:7” twist. The first barrel used in testing was 16” Colt HBAR with chrome lining, a NATO chamber and a 1:9” twist. The second barrel used in testing was a 20” Colt HBAR, also with chrome lining, a NATO chamber and of course a 1:7” twist. The longer barrel with the 1:7” twist was purposely chosen for the increased muzzle velocity coupled with the 1:7” twist. Both barrels had free-float handguards.

Accuracy (technically, precision) testing was conducted from a distance of 100 yards following my usual protocol. The fore-ends of the weapons rested in a Sinclair Windage Benchrest and the butt-stock rode in a Protektor rear-bag. Sighting was accomplished via a Leupold VARI-X III set at 25X magnification and adjusted to be parallax-free at 100 yards. A mirage shade was attached to the objective-bell of the scope. Naturally, the wind conditions were monitored using a Wind Probe. The set-up was very similar to that pictured below.





Four 10-shot groups of the PPU M193 were fired from the 1:9” twist barrel. Those groups were over-layed on each other using RSI Shooting Lab to form a 40-shot composite group. The mean radius of that composite group was 1.08”.

As with the 1:9” twist, four 10-shot groups were fired from the 1:7” twist barrel.  Those groups were also also over-layed on each other to form a 40-shot composite group; the results were nearly identical to those obtained from the 1:9” twist barrel.   The composite group had a mean radius of 1.01”. The two composite groups are shown side by side for comparison.






Testing performed by C.E. Harris at Aberdeen Proving Ground and later at Sturm-Ruger has shown that the “overstabilization” claim is largely nonsense. The testing showed that “overspinning” quality light-weight bullets from a fast twist barrel does not become an issue unless you have a gyroscopic stability factor greater than 5.0 (which would require something along the lines of a 1:6” twist barrel launching a 55 grain bullet at over 3500 fps) or unless firing at an angle greater than 85 degrees.

After the U.S. Military adopted the 1:7” twist for the M16A2, C.E. Harris did extensive testing comparing the accuracy of light-weight bullets fired from 1:10” twist barrels and 1:7” twist barrels using 52 grain Sierra MatchKings. The accuracy testing was done from 200 yards, (well into the downward slope of the trajectory where the Internet Commando claims that all manner of evil befalls the “overstabilzied” bullet), and the accuracy results from the two different twist barrels were also nearly identical.





Quality, modern lightweight bullets (40 to 55 grain) of typical copper-jacket/lead-core construction can shoot superbly from fast twist barrels.   Typical 55 FMJ bullets do not fall into the quality category.


The group pictured below was fired from a 1:7" twist Noveske barrel using 40 grain V-MAX bullets.






The 10-shot group pictured below was fired from a distance of 100 yards from a Noveske barreled AR-15 with a 1:7” twist using 55 grain BlitzKings.





The 3-shot group pictured below was fired from the same 1:7” twist barrel for the Internet Commandos in our viewing audience also using the 55 grain BlitzKings.







The next 10-shot group pictured was fired from a Krieger barreled AR-15 with a 1:7.7” twist using 55 grain BlitzKings.





Here's another example of just how well a 1:7" twist barrel can shoot light weight bullets. While the group pictured below was fired from a distance of only 50 yards, it's a 10-shot group fired from a chrome lined, NATO chambered Colt barrel with a 1:7" twist using 52 grain Sierra MatchKings.








A 14.5" Colt M4A1 SOCOM  barrel,with its NATO chamber, chrome lining and 1:7" twist can shoot quality 55 grain bullets quite well.






A 1:7”  twist rate does not have a negative effect on the terminal ballistic properties of M193 and M855.  From Dr. G.K. Roberts . . .

"The U.S. Army Wound Ballistic Research Laboratory conducted terminal performance testing using 5.56 mm 55 gr M193 FMJ ammunition fired in 20” barrels of 1/14, 1/12, 1/9, and 1/7 twist rates. No difference in terminal performance was noted between shots made with the different twists. Similar testing was conducted with 5.56 mm 62 gr M855 FMJ ammunition fired in 1/9 and 1/7 twist barrels. Again, no difference in terminal performance was noted."











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Interesting.  I have used it without issue in my recon and use it now with a 13.7 inch noveske midlength barrel for coyote hunting with great effect.  I look for the same pressure signs I would generally look for on my handloads and find no issues.  I guess I should get a fancy kreiger set up in 5.56.

I might try some lighter rounds. But the Hornady stuff hasn't been good for me thus far.

Thanks for that, Molon. I will look into some lighter rounds then. :) But were any of those from factory loads? Or hand loads? I don't load my own ammo. I don't have the space nor the equipment. Not the know-how. So I will have to stick with factory ammo.

Start with some of the factory loadings that use a 52 grain BTHP (Sierra MatchKing, Nosler Custom Competition, Hornady BTHP).

I have a lw profile 16" noveske stsinkess barrel and have found the 55gr Sierra blitzking to be the most accurate and consistent bullet out of everything I've tried. Specifically the Australian outback 55gr blitzkking .223 load. It can be had for relatively cheap and is while I have shot great groups with other brands, Ive found the a.o. ammunition to be untouchable in consistency. They also make a 69gr match king load which is also extremely consistent and the most accurate 69gr smk load I've found. I shot groups back to back with fgmmk and it blew the federal gold medal load out of the water. Of course every barrel is different and it's possible the next barrel that came off the line after mine hates the stuff but I havent found a single negative post regarding the Aussie outback ammo.

I haven't been able to find any factory ammo with the Sierra 52gr MK bullet. I did pick up a few boxes of Nosler Custom Comp to try though.



When you say "out of everything I've tried..." what other ammo have you tried? Where can I buy AO ammo? I clicked on their US retailer link on the website but it takes me to an importer's website. Haven't found any places to buy it though...

I'm also in San Francisco, so ordering ammo online is tricky because a lot of retailers refuse to ship here. Cabelas ships here, as does TargetSports USA, and BulkAmmo.com. But a lot of other places won't.

Mostly i agree with you, but BH MK262 is pretty damn accurate ammo.

http://www.sgammo.com/manufacturer/adi-outback

Sam is a good guy, and a site sponsor too. He's the only place I've seen selling it.

Only if it ends up ripping itself apart in the air.  Otherwise, no.

Gorilla 77gr SMK rounds have performed very well for me from an 18" 1/8tw and a 14.5"&16" 1/7tw.

I have never been able to get the 75 Black Hills to shoot well in any rifle.

The 75 grain Hornady Match load, on the other hand, always seems to be pretty accurate.

I have been buying Fiocchi 50 grain V-MAX because it is fairly inexpensive and locally available, and it is also quite accurate.  The most accurate factory load I have tried is the HSM 52 grain Sierra, but I have not seen any in a while.

I've never shot the 75gr Black Hills. But I did shoot the Hornady Match 75 and posted a photo of the target above. My rifle did NOT like it. 77gr BH shoots much better in my gun. I have some Nosler 52gr loads to try. I will look for HSM though, thanks!