Awesome powder and primer combination!!!!

Attachment 5282

In the quest for sub MOA accuracy from my Model 10T-SR in 223 I've replaced the stock and pillar bedded the action and tried many different bullet weights with CFE223 to no good end. Frustrating because my other Savage Model 10 in 223 LOVES that powder. A competition shooter friend of mine turned me onto Alliant AR-Comp so I started to do some research. Load data is VERY hard to come by for any given bullet weight/type so far. I did not trust what I found in the Alliant site because one load for 50gr bullets called for 27.4 grains, 25 grains of the stuff fills the case to the rim!!

So, I called Alliant and got in touch with a tech who reloads for a 223 and exclusively shoots AR-Comp. He informed me that the charges shown on their website (the few that they have) should be considered max and that we should deduct 10% and use that as a starting point. At this time they have no data for any 60 grain bullets with that powder in .223.

He told me that he is getting SD in the SINGLE DIGITS when loaded slightly below max over CCI BR-4 primers. I bought a pack of BR-4 and loaded the Nosler 60s over 24 grains and a BR-4 primer. The SD for a five shot string was...........3.4!!!!!!!! I also loaded Hornady 73g ELD-Match over 22.5 grains and a Rem 7 1/2 primer and shot a 5 shot group that measured .219 inch for the first four shots and the fifth shot opened the group to .354 inch. SD was 22.5. I'm excited and plan to do some testing with those two loads by playing with seating depth, powder charge, neck tension etc to see if I can get consistent low SD and bugholes at 100. My goal is to find a load that will deliver 1/4 MOA accuracy shot after shot.

From what I've read online the Alliant techs swear by the magic created with AR-Comp and BR-4 primers. One test that I found on youtube compared 4198 and AR-Comp and when the load density hit the magic level with the AR-Comp the SD dropped to single digits.
I may have an eight pound keg of CFE223 to sell!

The 73gr ELD? Is your 10T a 1-9 Twist?

I have been using AR-comp in both 223 and 308 in AR style rifles with very good luck. I have found the burn rate on AR-comp is extremely close to IMR 3031. I have had the best accuracy out of my AR-10 with 3031, which led me to try some of the AR-comp. It has been 6+ months since I have shot it, so I can not remember the exact group sizes, but nothing sticks out in my mind as bad. I think the groups were close to about the same size.
I have not had a chance to try and 3031 in 223 to see how it compares to the AR-comp, but I do plan on it. I am just in the middle of moving and it will be a while before I can get back to shooting.

Quote:

---

Originally Posted by wbm

The 73gr ELD? Is your 10T a 1-9 Twist?

---

Yes it is. I know it is iffy with a 73 gr bullet in a 9 twist but it looks promising at 100. If it is repeatable then I will see how the groups hold together at 200 and 350.

IMR 3031 and a 53 gr. V-Max are a quite accurate and potent combination in my 9 twist Savage. I find IMR 8208 XBR better on the heavier bullets like 69 gr. SMK and TMK. The 53 gr V-Max is an effective 500 yd bullet due to it's remarkable B.C.

You don't mention at what altitude you typically shoot at, so the 73 gr. ELD or 77 SMK may or may or not work. Some 9 twist barrels will shoot the 77 SMK fine. Mine doesn't. Actual barrel twist, bullet velocity and air density are major determining factors.

Measure your barrels twist accurately as possible and report back. Also use the Berger twist rate calculator after measuring your particular bullets dimensions. Keep in mind that the plastic tip affects the bullet center of gravity in stability calculations in case your particular bullet is not on a drop down menu in the calculator. In that case, you cannot depend upon data based upon a Hollow point or soft point bullet of same length and weight.

At this point I've not verified the twist rate of my barrel but will get that done. The Berger calculator shows a marginal stability factor of 1.3. I'm at 4,500 feet ASL.

How do you compensate for the plastic tip in the Berger calculator?

Edit. I verified the twist rate today by putting a tape flag on a cleaning rod with a bore brush on the end. The flag came back to top dead center twice in 18 inches. Guess that makes it a 9 twist.