OCW test 204R updated

[Hedge]

For those of you who are working on developing a load for your 204R, I thought I'd share a test I'm doing using the Optimum Charge Weight procedure developed by Dan Newberry. http://optimalchargeweight.embarqspace.com/

I modified it a bit in that I picked the max load I wanted and kept dropping charges in 2% increments until I hit minimum.

I used 3 shot groups in round-robin from a clean barrel. 6 total zeroing and fouling shots. 2 minute intervals between shots. The sequence is 1-3 on the top and 4-6 on the bottom.
Here is a pic of the results:



You can see that groups 2,3 and 4 produced similar sizes and impact locations, just as Newberry described. Based on that, I chose the load for group 3 as my OCW. According to the theory, I now have a charge weight that can vary +/- 2% and still group them closely. Note that groups 1 and 6 have 2 bullets in 1 hole each with a "flyer". Newberry advises against considering them as they are not variable tolerant.

From there, I set up a test to find the best bullet seating to shrink the group as shown here:



For this combination of components, it looks like 0.060" freebore is where I should start. The next step will be to work +/- .005" to see if I can tighten it up even more. I'll be shooting 5 and 10 shot groups for verification. Using 3 shot groups is just a quick way to get in the ball park.

Hope this helps some of the newer reloaders in quickly finding a load for their 204 or any other caliber rifle.

I'll post the results of my final tests when the weather permits. It's lousy hot and humid here.

Hedge

Weather cleared up and I got to shoot my test loads. 3 fouling shots and then 3 5-shot groups in round robin with 2 minutes between shots. Seating depths at .055", .060" and .065" from lands.

Here are the results. Got a little excited on the forth shot of the 1st group and squeezed off too soon. Target squares are 1". I skipped the 10 shot sequence as to my mind, 4 hits in 1 hole, round-robin iisn't a fluke.

On the previous test using 3 shot groups, the .060 seemed promising but 5 shots gives a better picture. At any rate, there's the sequence of load development I'm using. Seems to work with a minimum of rounds. The Ladder test should be just as valid but requires a longer range than most of us have at our disposal.

[Trent]

Thanks for posting this Hedge. If you get around to shooting more groups with that .055' jump load that you developed I'd like to hear the results. Thanks for posting all the photos and the write up.

[Hedge]

You're welcome, Trent. I'll do that.

I did throw together some rounds for a quick test, tonight. Shot 'em and got similar results, but then I discovered I mixed Hornady and Win cases. Can't really make an exact comparison but the grouping was close enough to say there is a significant difference between .060 and .055 groups. The 0.055's are tight and the 0.060's are shotguns. Got me scratching my head as to why a mere .005" would make such a difference. If it really does, it's going to make reloading a pain because I've found as much as .003" difference in ogive with bullets of the same batch.

I'm in the middle of testing Benchmark loads right now. Can't say my rifle likes it as much as the 8208XBR, though. Just not getting the tight groups many people seem to get.

[Joe O]

Don't blieve anyone has posted results with the 26gr Barnes before.What other bullets haveyou tested?

[Hedge]

Tested 40 gr. Vmax with excellent results
40 gr. Nosler - so far, doesn't like the same loads as the Vmax. Still testing.
39 gr. Sierra - not as good as the Vmax in my rifle
32 gr. Vmax - working on that one but looking good

[DoubleUp]

Hedge, it appears to me that your group 4 does not have the same POI as groups 2 and 3. In fact it looks like group 4 is moving up toward groups 5 and 6. Groups 2 and 3 are reasonably close, but perhaps not close enough to be sure of a true OCW node. The fact that your original .060 good group fell apart in subsequent testing is a further indicator that your OCW node might not be there. While you did find pretty good groups with the seating at .055 and .065 that doesn't mean you have the best node. Others may tell you differently, but with the 204 Ruger, I'd rather go in .2g increments because the nodes aren't all that wide at times. You might consider loading 28, 28.2, and 28.4 and see if the 3 rds. group together. If so, then 28.2 would give you some leeway. At the very least, you may want to repeat your orignal OCW to verify the same results again. You can also download the following program for free which helps in determining group POI. I'm sure you'll have her driving tacks before long.

http://www.6mmbr.com/ontargetsoftware.html

[Hedge]

DoubleUp,

Thanks for taking the time to look this over. I appreciate it.

Thought I'd already replied to your post, but seems I must have messed up. At any rate, I'll try again.
Also sent you a PM but that seems to have gone into the ether, as well.

Downloaded the software. Nice program! Every load developer should have it.
I plotted the targets from groups 2,3 & 4 to see the avg POI. I'm not seeing what you describe. The POIs are only tenths of an inch in variation and around 3 o'clock. Am I missing something?

Like your idea of re-shooting the groups. I'll do that, only this time with a .055 jump to the lands on all rounds.

As an aside, I talked with a friend who used to develop exotic munitions for the gov't. He also did a lot of work on long throated tubes.
When I asked him about the dramatic difference in groups between .055" and .060" jumps he wasn't surprised. Said it wasn't uncommon to find a very narrow 'sweet spot' like that.

I'll post the results of the next test to let you know what happened.

[Trent]

I get the extreme pleasure of shooting with Mr. Jeff Block a few times a month in silhouette matches. I had already been using his On Target software prior to meeting him. He is a gentleman and a very bright programmer. Dedicated to the shooting sports.

[DoubleUp]

Hedge, I didn't get the PM. You might try posting your results over on Dan Newberry's site.

http://practicalrifler.6.forumer.com/vi ... a30b319223

I'm sure the collective wisdom of Dan and the other guys there can give you a far better analysis than I'm able to do.

What I see is that your group 4 is already moving vertical toward where your groups 5 and 6 are located. That could mean that group 4 isn't stable with groups 2 and 3. That's why I suggested dropping down to 28, 28.2 and only going to 28.4 to shoot the 3 shot verification load. If those three rds. group together, then you have a good solid node that will stay stable up to .2 above or below the 28.2.

Anyway, Dan's the man on OCW and it would be worth your while to get his wisdom on what you have and what your next best move would be. Keep on it, and it will work out I think.

[Hedge]

DoubleUp,

Just registered with Dan's site. Awaiting admin.

In the meantime, here's a pic of the groups with On Target overlay just to be sure we're talking about the same groups.



Let me know.

Hedge

[DoubleUp]

Hedge, it isn't a large amount of movement for group 4 at 28.6g from 28.3 and 28 which are very close. However I'm also looklng at how it compares to groups 5 and 6 where we see a more pronounced upward movement. All I mean is that it appears the upward movement is already beginning at 28.6, so your more stable node might only go to 28.4. That's the reason for my suggestion of shooting three rounds loaded at 28, 28.2, and 28.4 to see if those three would shoot in a single good group. You would probably only be dropping .1g from your assessment of 28.3 as the OCW, but might be more stable there.

When you get your post on Dan's site, they will give you the right advice on what you have and where you need to go next. Those guys want to help people much like the folks here, and like here, they manage to do it without trying to humiliate anybody or tell them how stupid they are. I've learned a lot from both boards, and most of the people here or there know a whole lot more about this stuff than I do or probably ever will know. We're all trying to help each other get good results.

[Hedge]

I'm in and posted.

Thanks, DoubleUp. Sure appreciate your interest in helping me out.