.223 loads with IMR4320


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7mmsavage
July 15, 2013, 07:07 AM
Needless to say powder's been tough to find locally, so I'm trying to make do with what I have on hand, which like he title says is IMR4320. I'd just like to get some opinions before I go out shooting an unfamiliar load. Here's what I've got:

Shooting an AR type rifle, 20" 1-9 barrel. Using Hornady 55 gr. fmj with canalure, seated to OAL of 2.200

I have 4 loads starting at 23.5gr working up to 25, in half gr increments, using a combination of info from both Hornady and Hogdon manuals.

The OAL of 2.200 puts the canalure completely beneath the case mouth. I know that in itself won't hurt anything, but find it strange that Hornady made the bullets, and recommends a seating depth that far off the canalure. On the other hand, they do fit well in the magazine, where a dummy seated to the middle of the canalure is really tight.

The 25 gr load fills the case to the bottom of the neck, so I'm going to proceed cautiously, and inspect the other cases for signs of pressure before I fire the max load.

Any experiences with this combination, or advice and opinions would be appreciated. I won't be headed to the range for about a week, so I've got time to change things if need be. Thanks guys.

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warhwkbb
July 15, 2013, 10:45 AM
I just loaded a few boxes of 223 with 4320 using 55g SP bullets. I have not had a chance to test them at the range yet. My Sierra data shows up to 26.1gr which fills the case and may be slightly compressed at the COAL listed. I started at 25.5 and will work up as needed. Surprisingly, 4320 fed through my RCBS UniFlow fairly accurately. 4320 does not seem to be a popular powder for 223 so I too am interested to see others results.

GooseGestapo
July 15, 2013, 11:26 AM
IMR4320 is very, very similar to RL15 in density and burning rate. It's the military's powder of choice for the 77gr OTM load. IMR4320 is a tad slow for .223 (as is RL15), so will give better performance with heavier bullets and longer barrels.

I've used RL15 extensively in 55gr and heavier loads in my AR. Shoots fine. Most likely you'll find the max loads are whatever you can get in the case and still seat a bullet....

My 60gr-65gr load is 26.5gr RL15.
55gr load is 27.5gr which is about most you can get in the cases (Winchester and Remington commercial).
Accuracy is a function of how good a bullet you use. A Sierra (regardless of weight, 55gr or heavier) is 5-shots under MOA.... My favorite deer bullet is 65gr Sierra GameKing, though I've got and used mostly 60gr Hornady's... They both hold together well and ususally give complete penetration.

7mmsavage
July 15, 2013, 12:09 PM
Thanks for the info guys. Makes me feel a little less nervous about these loads. Once I figure which of these work best, I'll use up the remainder of this powder, then hopefully find something more. 223 appropriate.

Any thoughts on the seating depth /canalure issue, or am I thinking too hard about it?

joustin
July 15, 2013, 03:22 PM
When I load 55gr fmj's I set the oal so that the brass is in the middle of the canalure.

Sent from my DROID RAZR using Tapatalk 2

NCsmitty
July 16, 2013, 08:25 PM
IMR4320 is an excellent powder in the 22-250, and is a bit slow for the 223, but in these days of shortages, it will suffice. The next step slower burning to Varget, according to Hodgdon's site.


NCsmitty

FM12
July 17, 2013, 04:22 AM
Try H 335 ifn you get a chance for 55 grain and under.

7mmsavage
July 17, 2013, 11:53 AM
Thanks again guys. I just got my hands on some accurate 2495 that should be more appropriate for my needs, but I'm still going to use up this 4320 first. It's just for informal target shooting anyway, so really I'm happy if it just safely goes bang. The weekend is slowly but surely crawling closer, so I'll have a range report soon.

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