5.56 powder testing results with 75 gr.

[budlight]

Hornady Match Bullets 22 Cal (224 Diameter) 75 Grain Hollow Point Boat

Hornady has pushed their Match bullet design to the limit, then put them through painstaking production controls and strict testing to ensure they are...

www.midwayusa.com

Right now I have plenty of time and a new chronograph. I used a lead sled with a 40 pound ford flywheel in the middle of it and two 25 pound bags of shot to eliminate human error. I used my best match grade ar-15 with a stainless 20 inch barrel. rifle length piston system with a smaller .072 hole in the barrel.

For light pills my go to powder is CFE. 62 grain and heavier the go to is AR-comp and in the past H414. Both produce excellent groups at 200 yards . This is an older picture of what the barrel can do at 200 with 62 gr hpbt and h414.

Anyway the new powder is Alliant MR-2000. 75 is about the longest practical bullet for 223 cases and mags that keep the round to approximately 2.260 OAL. Max load is 26.4 , I did .2 grain increments to save time. best groups and it was 85 F at 4800 feet was 26 grains. Then it was chrono time with 26.0 I was right at 2938 avg 8 es. Lake city brass. AR-comp was 50 fps lower at listed max and CFE was 100 fps slower at listed max.

I wish that I brought my target 24 inch, but i figured that most 223 people kind of have 20 inch barrels. The BC for the 75's is .395 and 2938 fps downloaded with dime size 200 yard groups is just a great varmint round.

Alliant Powder - Power Pro 2000-MR

www.alliantpowder.com

I did the flier off to the left!

 

[budlight]

Forged upper and lower. Nickle boron bolt. 2.5 pound drop in trigger. Match grade 20 in SS rifle length gas system. hand lapped, polished feed ramps, and bore. Vortec viper scope 6X24X50mm

 

[Tiny Tim]

Its amazing how well those AR's shoot. And nice looking rifle! I have a similar set-up with a Green Mountain barrel and large port brake. FUN is all I can say about it!

 

[nksmfamjp]

How was accuracy with 75gr bullets? I'm building around LC 16 brass, CCI 450's, CFE223 and Hornady 75gr bullets. Best groups are 0.52" for 5 At 100yds.

also, have you considered H4895 or VARGET for the temperature stability?

 

[budlight]

How was accuracy with 75gr bullets? I'm building around LC 16 brass, CCI 450's, CFE223 and Hornady 75gr bullets. Best groups are 0.52" for 5 At 100yds.

also, have you considered H4895 or VARGET for the temperature stability?

I have never bought H4895 or varget. New powders have some outstanding qualities. I test on hot days so I know that I won't have a future problem. CFE 223 just doesn't have the speed with heavier bullets. putting in the listed max it was still 100 fps slower than under loaded 2000 MR in both 18 and 20 barrels with rifle length gas systems. I don't own shorter barrels to test.

I like shooting for groups far enough away that I can't see the holes in the paper. That way you are not correcting your aim point. I shoot at a little dot and don't know how the group was until you retrieve the target. 200 yards is a good distance

The accuracy of the 75 is very good. It is made for long distance shooting. Some of the bullets went through the same hole

 

[nksmfamjp]

The accuracy of the 75 is very good. It is made for long distance shooting. Some of the bullets went through the same hole

What is very good at 200?

 

[budlight]

sets of less than one inch groups. We are packing up for a ground squirrel hunt. the ranchers just had another cutting so the fields will be bare. We will see what the hit ratio is out to about 400 yards

 

[nksmfamjp]

That sounds great. Good luck. My best groups so far are 0.48" at 100 with CFE223. velocity= 2384 FPS. Sd = 12.3
Seems kind of like a fluke group and Sd/velocity too low...

Trying to redevelop at 2900 fps, but not at a node yet

 

[Nomosendero]

I know we have "fast" & "slow" barrels out there, but how much slower is the 18" with your best loads compared to your 20"?

 

[budlight]

I know we have "fast" & "slow" barrels out there, but how much slower is the 18" with your best loads compared to your 20"?

18 inch barrel averaged 62 fps slower at 2876. The 18 barrel was also a 1:8 where the 20 is 1:9 both are Wylde chambers and I forgot to state Rem 7 1/2 small rifle BR primers for consistency on testing.

 

[Nomosendero]

Good to know, I think the 18" is a sweet spot for the way I use an AR, Truck gun, Varmits, Hogs and occasional target and maintain decent velocity. I do not have a 22" to compare velocity right now.
Thanks for the info.

 

[imyourhuckleberry]

I reload only Hornady 75gr BTHP match bullets for my AR. I have the Rock River Arms Predator Pursuit, with the 20" barrel and at 200 yards I sub moa 5 shot groups using RL15 powder.

 

[lotech]

I seldom use anything but TAC or H4895 (preferred) for AR .223 loads. In two Colt ARs (1 in 7"), I tried the 75 Hornady and the 68 as well. Both were reasonably accurate, the 75 being slightly better, but neither would do quite as well as the Sierra 69 MK or 65 GK. However, the Hornady bullets are considerably cheaper. If I had a gun that shot them well, that's all I would use.

 

[Tyler Kee]

I love that bullet. Buy it in bulk and have shot it through 12.5", 16", and 20" guns. Datapoints on CFE vs Varget are below.

*****Disclaimer***** these loads are safe in my guns. Do not replicate in your guns.

20" Armalite w/ 5.56 NATO chamber

This is a 1:9 barrel, so I haven't done a ton with the 75 gr bullets. I did pick up a pound of CFE at one point and figured it might be fun to push some 75s and 55's through it.

26 gr of CFE + 75 gr Hornady BTHP = 3 shot .8 MOA group @ 2936 fps.
28 gr of CFE + 55 gr Hornday FMJ = 3 shot 1.1 MOA group @ 3268 fps

The other charges were pretty erratic for both velocity and SD.

16" OdinWorks barrel w/ 223 Wylde chamber

23.8-25 gr of Varget+75 gr BTHP gets me 2575-2682 fps - I tune charge weight based on the brass I'm using to get desired SD & accuracy. 2600 fps seems to be a sweet spot. My workups using LC brass were a bunch of 5 shot groups hovering between .6-.8 MOA. Incredibly consistent, though going much above 24.5 gr is compressed and going to 25 gr usually starts deforming bullets trying to cram powder in.

12.5" ??? barrel w/ 5.56 NATO chamber

23.4-25.8 gr of Varget + 75 gr BTHP got me 2286 - 2481 fps.
Max book of CFE is 26.5 gr and it was popping primers at that charge weight, but I did get velocity of 2595 fps.

Final thoughts

I've never been blown away by the accuracy potential of CFE, but I will freely admit that it's a speed demon that meters VEERRRRRYYYY easily in my chargemaster. When I have more time and money, I'll put together a CFE+75BTHP load for the SBR that I can crank out in volume. That 75 gr BTHP is supposed to be a pretty decent (budget) home defense & hunting bullet.

For the 16" & 20" guns, I care a lot more about accuracy at the expense of speed, so I stick with Varget, but I would love to find a Varget load with good speed that shoots well in both so I can crank those out in volume as well.