Both of these rounds seem to have expansion at a pretty low velocity (approx. 1700-1800 fps) . The factory loads from a 8 inch barrel seem to come in right around 2000 fps. is there any reason they cant be loaded at 5.56 pressures? that would be around 2400 fps from an 8 inch barrel and would give you expansion out to about 200 yds. Has any one tried this or am I asking a dumb question? Also, Lehigh defense makes a new Controlled Chaos 62 grain that has an advertised threshold of 1450 fps... Is there any validity to there rounds or are they gimmicks like all the other "Black ops super tactical" frangible ammo?

 

Previously they were, but agencies were running 5.56 in 223 chambers so Speer quit making it, the 223 being adequate.

I hand load the 62 grain Fusions/Gold Dots from RMR and shoot them from a 10.5" pistol. They expand well at pistol velocity. I tested them at 50, 100 and 200 yards. They expanded well at those distances. I have not chronoed them yet.

 

I think you're overestimating the velocity of a 5.56 pressure Fusion round. Here's my velocity testsfrom a 10.5" barrel last fall and winter.

Please note the difference between Fusion (.223) and Fusion MSR (5.56).

There is no way you're going to get 2400 fps from an 8" barrel with a GD or Fusion bullet.

Fusion MSR is not a 5.56mm load.







...

If someone is going to correct me, I like it be Molon. You are of course correct Sir!

A more appropriate way to state it would be that MSR is a hotter .223 load and much closer to 5.56 than the standard Fusion. I still don't think you can get 2400 fps from an 8" barrel but I'm standing by to be corrected.

Lots of good info in this thread, especially since I'm going to be loading up some 62gr fusions for my 10.5.

Unfortunately, I don't have an 8" barrel, so I can neither confirm nor deny that statement.  

The information below will provide a little insight pertaining to the velocity of a 5.56mm 62 grain soft-point load.



Hornady 5.56mm 62 Grain TAP Barrier Ammunition











Hornady’s 5.56mm 62 grain TAP Barrier ammunition (#8125N) is loaded with a 62 grain flat-base, soft-point bullet with a cannelure.   This bullet has the largest amount of exposed lead at the meplat of any of the soft-point barrier-blind loads that I’ve evaluated.













Contrary to erroneous information that has been posted on the Internet, the bullet used in this ammunition is not a bonded projectile.








The case mouth is crimped and has an anaerobic sealant.









The primer pockets of this ammunition are crimped and have lacquer sealant.  The case-heads read, “Hornady 5.56 NATO”.  Hornady advertises that the ball powder used in this ammunition is temperature stabilized and has a flash retardant.  The box label carries a warning that this ammunition is "NOT FOR USE IN .223 CHAMBERS".








Hornady advertises that this ammunition has a muzzle velocity of 3078 FPS when fired from a 20” 5.56x45mm NATO test barrel.  For comparison, the US mil-spec for the velocity of M855 ammunition is as follows:

MIL-C-63989C [Amendment 4] states that the average velocity of the cartridges “shall be 3,020 feet per second (fps) plus or minus 40 fps at 78 feet from the muzzle of the weapon. The standard deviation of the velocity shall not exceed 40 fps.”  This specification is for a 20”  barrel and depending upon variables equates to a muzzle velocity of approximately 3105 FPS (plus or minus 40 FPS.)



As an aside, after reading the above specification, some of you may be wondering, “Why 78 feet from the muzzle?”  The answer to that question is that this specification is simply an historical hold-over from the days when “circuit” chronographs (e.g. Le Boulenge Chronograph and the Aberdeen Chronograph) were used at Aberdeen Proving Ground, Frankford Arsenal and Springfield Armory.  These types of chronographs required a significant distance between their first and second screens to produce accurate results.

As an example, when using the Boulenge Chronograph, the first screen of the chronograph was placed 3 feet in front of the muzzle and the second screen was placed 150 feet beyond the first screen.  For those of you who might not be aware of the following fact; chronographs determine the velocity of the bullet at a point that is midway between the first and the second screen (i.e. not at the location of the first screen).  Therefore, with the above spacing, the velocity of the bullet is determined for a point that is 75 feet from the first screen.  So, add the three feet (from the muzzle to the first screen) to the 75 feet (the midway point of the screens) to obtain the “78 feet from the muzzle” distance.













I chronographed the Hornady 5.56mm 62 grain TAP Barrier  ammunition from a semi-automatic AR-15 with a chrome-lined, NATO chambered 20” Colt M16A2 barrel.









Chronographing was conducted using an Oehler 35-P chronograph with “proof screen” technology. The Oehler 35P chronograph is actually two chronographs in one package that takes two separate chronograph readings for each shot and then has its onboard computer analyze the data to determine if there is any statistically significant difference between the two readings.  If there is a difference, the chronograph “flags” the shot to let you know that the data is invalid.  There was no invalid data flagged during this testing.

The velocity stated below is the muzzle velocity as calculated from the instrumental velocity using Oehler’s Ballistic Explorer software program. The string of fire consisted of 10 rounds over the chronograph.














Each round was single-loaded and cycled into the chamber from a magazine fitted with a single-load follower. The bolt locked-back after each shot allowing the chamber to cool in between each shot. This technique was used to mitigate the possible influence of “chamber-soak” on velocity data. Each new shot was fired in a consistent manner after hitting the bolt release.  Atmospheric conditions were monitored and recorded using a Kestrel 4000 Pocket Weather Tracker.









Atmospheric conditions

Temperature:  78 degrees F
Humidity:  54%
Barometric pressure:  29.99 inches of Hg
Elevation:  950 feet above sea level


The muzzle velocity for the 10-shot string of the Hornady 5.56mm 62 grain TAP Barrier ammunition fired from the 20” Colt barrel was 3069 FPS with a standard deviation of 18 FPS and a coefficient of variation of 0.58%.  






....


I conducted an accuracy (technically, precision) evaluation of the Hornady 5.56mm 62 grain TAP Barrier ammunition following my usual protocol.  This accuracy evaluation used statistically significant shot-group sizes and every single shot in a fired group was included in the measurements. There was absolutely no use of any group reduction techniques (e.g. fliers, target movement, Butterfly Shots).

The shooting set-up will be described in detail below. As many of the significant variables as was practicable were controlled for. Also, a control group was fired from the test-rifle used in the evaluation using match-grade, hand-loaded ammunition; in order to demonstrate the capability of the barrel. Pictures of shot-groups are posted for documentation.

All shooting was conducted from a concrete bench-rest from a distance of 100 yards (confirmed with a laser rangefinder.) The barrel used in the evaluation was free-floated. The free-float handguards of the rifle rested in a Sinclair Windage Benchrest, while the stock of the rifle rested in a Protektor bunny-ear 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. Wind conditions on the shooting range were continuously monitored using a Wind Probe. The set-up was very similar to that pictured below.









The Wind Probe.







The test vehicle for this evaluation was one of my semi-automatic precision AR-15s with a 20” stainless-steel Lothar Walther barrel.  The barrel has a 223 Wylde chamber with a 1:8” twist.









Prior to firing the Hornady 5.56mm 62 grain TAP Barrier ammunition, I fired a 10-shot control group using a hand-load topped with the Hornady 73 grain A-MAX bullet.  That group had an extreme spread of 0.82”.








Three 10-shot groups of the Hornady 5.56mm 62 grain TAP Barrier ammunition were fired in a row with the resulting extreme spreads:

1.79”
1.23”
2.44”

for a 10-shot group average extreme spread of 1.82”.  The three 10-shot groups were over-layed on each other using RSI Shooting Lab to form a 30-shot composite group.  The mean radius for the 30-shot composite group was 0.55”.



The smallest 10-shot group.







The 30-shot composite group.





…..


Range Dog awaiting departure.






....

Ironically, your data shows .223 75gr Gold Dot and 75gr 5.56 TAP SBR as having identical velocity (statistically) from an SBR. Your data also shows 62gr Ranger Bonded as going significantly slower than M855 62gr.

"5.56" is a pressure designation, as it were, and has nothing to do with velocity. Projectile composition, bearing surfaces, powder burn-rates, and a host of other factors are at play when discussing velocity. This is all well known to Molon, but something that others would perhaps be surprised to learn. I know I was taken aback when the 5.56 hornady load was performing EQUALLY from an SBR to the .223 Gold Dot, which has always been known as a "slower" round in whatever weight it's loaded (except for the 5.56 pressure loads, now discontinued to the public).

right, but the velocity would be comparable to a 10.5 inch barrel in my case. the reduced penetration from velocity and rate of expansion would come in to play here. Basically I am trying to figure out how to have the performance of a 10.5 inch barrel in an 8 inch barrel. these rounds seem to offer the best usable velocity, but come loaded pretty soft from the factory. I was wondering if there is something in the construction of the projectile that makes the added pressure from a 5.56 round unsafe if used in conjunction with these

Im not to hung upon that number. it is twice the distance I need. I just want to know if 5.56 pressure and velocity is doable with these rounds.

not really... if you get approx. 2250 from a 64 grain Winchester ranger and 2200 from a 77 SMK from a 7.5 inch barrel when loaded to 5.56 pressure... I figure at least 2300 sounds feasible. Even at 2200 with a B.C. of .310 that equates to about 500 fps less at 200 yds. and you would have an impact velocity of 1700 fps. Ballistics by the inch has 55 grain Remingtons listed at 2400, mr gunsandgear also tested 55 grains from an 8 inch ballistics advantage barrel and also got 2400. typically the 5.56 rounds get about 100-200 fps higher velocity then the .223 counterparts of a given weight. so that would be about 2500 fps and the avg wuld be 2400 fps.

Does anyone know the average velocity of Fusion 62gr MSR out of a 12.5" barrel? I used that round in a 16" Recce barrel for hunting last year but this year I'd like to shave off some weight/OAL especially with a 9" can at the end. Other option is to put together a 300 BLK upper specifically for this purpose (not interested at all in shooting subsonic).

 


 

I posted that link above to my velocity tests that has that answer.

@26 degrees F, I got 2657fps with Fusion MSR from a 12.5" BCM standard barrel.

My bet would be that 2200-2300 is doable with a 62gr bullet. Keep in mind though that B.C. can change based on velocity. A good example for data is Sierra's website. They published velocity banded B.C. data for their rounds. I've only ever seen Federal publish .310 B.C. at (is it?) 2750 fps. That's likely to change at some point as the bullet slows down.

The fusion MSR and fusion seem to have the same velocity despite the disparity from the advertised velocities. The chopping block had this round loaded over 24.4 grains of TAC and got 3084fps from a 16 inch barrel which is more then the advertised from a 24 inch barrel. So from a 12 inch... probably 2600+ with the same load specs used by the chopping block test

right, but its maybe a .02 difference. and most of the time it seems to increase as the velocity gets lower from the reduced atmospheric drag pressure that the bullet has to travel through. This isn't a rifle meant for hunting, so Im really not concerned past 100 yds. I just want to know what is possible, and there is no downside to having it perform at 2X the distance that I intend for it to be used at