OCW analysis help needed, and info to help pay the cost

[tucansam]

I shot my first (four) OCW strings today, and I have a ton of data to pour through. I am a little concerned about my ability to evaluate each group correctly, as many of them are so close to the same POI, I can't decide which average load should be my optimum. So if you with some experience might lend a hand, I will repay the community by posting all of the data I collected along the way, in the hopes that it might help others in a similar situation. I chrony'd all of my shots, and MV out of my particular rifle with these bullet/powder combos is something I've been trying to find. Standard internet reloading disclaimers apply. Thanks to all who have helped me so far with my previous OCW questions. Here comes the geek stuff....

Rifle is a Savage 12 in a BVSS stock, bedded, 26" factory 1:9 RH barrel, YHM QD comp on the end, YHM Phantom .223 can on the end. Strings were fired on 1 Jul 2013 from 0800-1030. Ammo temp was initially 84-86F and I note along the way when it changes. OAT was 85F, winds 1-4MPH from 90 degrees to the right and then less than 1MPH after about an hour of shooting. Baro P was 26.92 and DP was 60.5. My elevation was 2890 and DA went from 5479ft when I started to just beyond 5800ft when I stopped.

My five initial shots (for a little fouling and to wake the barrel up) were with old Winchester Ranger LEO 64gr softpoints, grouped like crap, and came in at 3079fps, 2996fps, 3058fps, 3065fps, and 3079fps.

My bullets were Hornady 75gr AMAX and 75gr BTHP. My powders were Varget and H335. I used factory new Winchester cases and WSR primers. Loads were done on a Lyman Spartan with Lee dies (upgrading to Hornady ASAP). OAL changed a bit, I will note it.

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75gr BTHP with H335. Ammo temp was 86.5F. 5571 DA, 87.8F OAT, with 1-3MPH winds.

First three rounds were 20.7gr (2487 fps), 21.1 (2464), and 21.5 (2530). Not shown.

OCW strings were:

1. 22.0gr @ 2594, 2619, 2561 fps
2. 22.2gr @ 2672, 2656, 2656 fps
3. 22.3gr @ 2640, 2715, 2710
4. 22.5 @ 2677, 2732, 2721
5. 22.7 @ 2710, 2749, 2726
6. 22.9 @ 2749, 2801, 2766
7. 23.1 @ 2824, 2801, 2783

OAL for these rounds was 2.36 (actually, OAL for all the BTHPs was the same). No pressure signs noted.

On target #1, the shot that landed in the black at 10 o'clock should have been on target #2. Target #7 has three shots on it.

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Same bullet with Varget. Environmentals were essentially the same, maybe a degree or two warmer OAT and not even 0.5 degrees warmer on the ammo temp. First three rounds not shown, 22.5gr Varget @ 2629fps, 23.0 @ 2688, 23.4 @ 2749. Again, no pressure signs noted, OAL 2.362.

OCW strings were:

1. 23.0gr @ 2783, 2801, 2766 fps
2. 24.1 @ 2801, 2812, 2830
3. 24.3 @ 2801, 2801, 2801 (not a typo!!!!)
4. 24.5 @ 2855, 2824, 2867
5. 24.7 @ 2855, 2842, 2879
6. 24.9 @ 2867, 2873, 2886
7. 25.1 @ 2892, 2873, 2917

Tight groups here. Hard to ignore that and focus on OCW!

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75gr AMAX with H335. 89.5F ammo temp, 93F OAT, 5895 ft DA. 2.422 OAL (all AMAX loads are this dimension). No pressure signs noted.

First three (not shown) were 20.7gr @ 2478 fps, 21.1gr @ 2578, 21.5gr @ 2619.

OCW strings were:

1. 22.0 gr @ 2721, 2640, 2624
2. 22.2 @ 2609, 2639, 2677
3. 22.3 @ 2704, 2704, 2699
4. 22.5 @ 2749, 2715, 2754
5. 22.7 @ 2699, 2743, 2766
6. 22.9 @ 2743, 2783, 2766
7. 23.1 @ 2801, 2812, 2760

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2.422OAL, 75 AMAX with Varget. No pressure signs. Ammo was 89.5-90F, OAT was 95F.

First three were 22.5gr @ 2564 fps, 23.0 @ 2688, 23.4 @ 2726.

OCW strings were:

1. 23.9gr @ 2772, 2789, 2772 fps
2. 24.1 @ 2789, 2818, 2795
3. 24.3 @ 2801, 2824, 2795
4. 24.5 @ 2812, 2842, 2812
5. 24.7 @ 2867, 2836, 2836
6. 24.9 @ 2867, 2879, 2873

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So that's it. Trying to determine what bullet/powder combo to start with, and what my OCW would be. Advice and opinions welcome. Hopefully the gun/veolicty data will help someone else along the way. And again, I loaded a few close to max published loads, and exceeded in some cases, per the OCW guidelines, but these are MY LOADS and are safe for MY RIFLE and cases were inspected after EVERY SHOT. YMMV.

Thanks to all.

 

[Dan Newberry]

At first glance it looks like the Varget loads performed the best--at least the accuracy seems much better with Varget.

I like 24.1 grains with the 75's... just work on seating depth a bit to tune it in tight. 24.3 is too close to a big POI shift at 24.5, so you don't want to use 24.3 in my opinion.

Dan

 

[tucansam]

I really appreciate the reply Dan. When I reloaded years ago, I now wish I had known about this method. Made finding a solid load out of the total randomness of unlimited bullet/powder combos pretty painless.

I'll work at 24.1 and see what I can get out of it. Any advice on seating depth? At 2.46" OAL I have no rifling marks on the test bullets and no trouble closing the bolt. Seems like I have a lot of room to work with in the chamber on this rifle.

 

[rduckwor]

Dan knows a hell of a lot more than I do, but I like 24.3 as well. I see little vertical shift from 24.1 and maybe a called flyer on the high shot.

I definitely believe that the 24.5 has a flyer based upon the other groupings which I think demonstrate your ability.

I really like Varget in .223/5.56 and I was prepared to think it was too slow for the round. H335 works pretty well for me with lighter bullets.

I shot an OCW group today using Varget that had an ES of 3 fps. Varget really seems to sing when you get it into the upper charge ranges.

Good luck with your work up and great job presenting useable and complete data.

 

[tucansam]

I appreciate the replies gentlemen. No ability here, just a balls-dead-accurate factory sample from Savage and a scope worth its weight in gold. And near perfect conditions for test day at the range.

And hopefully the extraneous data is helpful to someone; I've spent many hours scouring for load data with results and its always helpful when I find it.

Any suggestions on the next step? In my old reloading life, I'd just take the top two or three tightest groups and load 15 rounds each, then shoot three 5-shot groups to try to confirm. I realize now why OCW is so much better an idea. But can I safely go back to my "old ways" and load up some 24.1 and 24.3 and shoot a few 5/7/10 rounds groups to confirm?

Or should I split the difference and load 24.2 and see where it lands me?

Also, 3fps is an impressive extreme spread... Either you are as much a perfectionist with your charge weights as I am, or this powder is going to be my new go-to for whatever I own that will shoot it.