Problems with .223 load development.

[StraightShooter]

Hi guys, i am having lots of problems developing a consistent load for my AR. I have a colt upper (5.56 chamber) with a 1/7 twist barrel. I am using hornady 55 grain FMJ BT bullets, mixed headstamp brass, rem 5 1/2 primers, and ramshot tac powder. I loaded all of the rounds on a single stage press and checked the weight of each with a beam scale and they all should have been dead on.

First I shot 10 shots of some wolf brass cased ammo I bought at the gun show for comparison. Heres the data I got for that:

LOW: 3062
HIGH:3112
AV:2996
ES:50.4
SD:54.9

This wasnt too bad and I got a slightly better result with some Black Hills ammo. Then i shot the rounds that I loaded. First was 23.0 gr of Tac and the ES and SD was absolutely all over the place.

LOW:2392
HIGH:2844
AV:2651
ES:451
SD:132.8

At this point I was scared to go on but next I tried 23.7 grains of Tac:

LOW:2523
HIGH:2777
AV:2671
ES:253.5
SD:79.37

Better but still terrible. Next was 24.7 and 25.2 rains of Tac. Both were had almost exactly the same ES and SD:

24.7 GRAINS

ES:100.2
SD:39.43

25.2 GRAINS

ES:101.2
SD:34.0

This is the first time using Tac and my first time developing a load for my AR so i am not sure if it is the powder or the rifle that is causing the issues. I am used to loading for bolt rifles and for pistols. If anyone can give me some pointers as to what could be the problem I would greatly appreciate it.

[NRAhighpowershooter]

When I do load work.. all I care about is velocity, and grouping.. ES, and SD be damned....my .223 80gr 600yd load (2790fps av.) (25.5gr Varget CCI BR4, LC cases)has a ES of 76 and a SD of 60 but I can consistanly shoot 190's with it......

[StraightShooter]

That could be your problem right there in red.

Try shooting with the same headstamp in the same groups.

Case weight can vary between manufacturers due to differences in case wall thickness. Cases with thicker walls will hold less powder than cases with thinner walls (But that's not the issue here.)

Thats what I was going to try next. Also, I noticed that some powder was sticking to the inside of the case neck before seating a bullet because of the case lube. I assume that the bullet will push that powder down when I seat the bullet. There arent any bumps in the necks of the loaded ammo indicating that powder is getting trapped between the bullet and the inside of the case neck so I dont think that is an issue but thought I would throw it out there. I didnt tumble the cases after lubing/sizing, I just wiped them off, so I may tumble them to get the lube out of the neck next time. Thanks guys.

[30Cal]

ES of more than about 150 tells me your chronograph is probably lying to you.

[StraightShooter]

ES of more than about 150 tells me your chronograph is probably lying to you.

You know i thought about that but I did chrony 3 different factory loads and they were all around 45 to 70 in regards to ES. That would tend to rule out that possibility.

[Higbean]

Maybe it is because you are using small pistol primers instead of small rifle primers. Just a thought.

[mecam]

Thats what I was going to try next. Also, I noticed that some powder was sticking to the inside of the case neck before seating a bullet because of the case lube. I assume that the bullet will push that powder down when I seat the bullet. There arent any bumps in the necks of the loaded ammo indicating that powder is getting trapped between the bullet and the inside of the case neck so I dont think that is an issue but thought I would throw it out there. I didnt tumble the cases after lubing/sizing, I just wiped them off, so I may tumble them to get the lube out of the neck next time. Thanks guys.

Did you trim them to 1.750"?

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[ar15barrels]

You know i thought about that but I did chrony 3 different factory loads and they were all around 45 to 70 in regards to ES.
That would tend to rule out that possibility.

Which loads did you test first?
If you were testing towards the end of the day when lighting conditions are degrading, it would not suprise me to see funky chronograph readings.

Also, keep the chrono at least 10ft from the muzzle so you don't get false readings from muzzle blast.

[ar15barrels]

LOW: 3062
HIGH:3112
AV:2996
ES:50.4
SD:54.9

Does not compute.

[StraightShooter]

Does not compute.

oops should have been

LOW:3062
HIGH:3112
AV:3082
ES:50.4
SD:23.9

I put the wrong primers in my OP as well. I am using remington small rifle benchrest (7 1/2?). Im going to compare the ramshot tac again but with a different powder and see how it goes. Maybe try with and without the sky screens.

I test fired 2 types of Black Hills .223, some wolf steel case, and some wolf brass cased ammo.

[Jicko]

How many rounds per set?

That could be your problem right there in red.

Try shooting with the same headstamp in the same groups.

Case weight can vary between manufacturers due to differences in case wall thickness. Cases with thicker walls will hold less powder than cases with thinner walls (But that's not the issue here.)

Tech Ted hit it right on the nail, possibly...

Read up on the "weight" and "capacity" section in this article.

http://www.6mmbr.com/223Rem.html

Even with the same manufacturer, there are year to year differences.

[StraightShooter]

How many rounds per set?



Tech Ted hit it right on the nail, possibly...

Read up on the "weight" and "capacity" section in this article.

http://www.6mmbr.com/223Rem.html

Even with the same manufacturer, there are year to year differences.

10 rounds per set.

[Blacktail 8541]

I did an extensive load work up with Tac fireing about 400 rounds, and the 55 grain hornady. Tac was all over the place and had large extreme speads and SDs. Groups finally tightened up when I reached the 25.8 grain charge weight.
I used 3 different primer as well. Rem 7.5, cci mil spec and winchester sm rifle. The Remington 71/2 did ok at about 1 1/2 inch 10 shot groups. But the winchester group average shrank to under 1 1/4 inch, with 1 inch happening regularly. The extreme spead was still 50 to 70 for all groups tested and the standard diviation stayed in the low 20s on average.


From my experience Tac will not produce small numbers in SDs or extreme speads, but will group acceptably.

This is my blasting load:

Ramshot Tac 25.8 gr
Winchester or BHA brass
Winchester Sm rifle primers
OAL 2.20 no crimp
Velocity 2920 fps

This is not a max load. Brass life is very good and groups average between 1 an 1 1/4 inch 10 shot groups at 100 yards out of 3 different ARs.

Hopes this helps.