OCW load development

[smoothie25]

I shot an OCW test and am having troubles determining the sweet spot here. I used OnTarget software to find the POI for each load. I have an idea of which load to try next but want to get some folks' opinions first. Below are the specs of this gun/load

Gun: Tikka 30-06
Bullet: 180 AB
Powder: H4350
COAL: 2.710" .020

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[drakehammer]

I’m sorry, but it takes a lot of imagination and assumption to find any sweet spot in this series. These are all over the place. I’m sure you know all this but I’ll state some hints just in case you don’t. This is why 5 shots for each condition comes in handy. I would recommend you double check that your mounts, bases and stock are all properly tightened. Make sure you are shooting from a solid rest and or bags that will let the gun recoil straight back into your shoulder, in a comfortable position, with no torque on the stock from your hands.

Personally i would suggest repeating this sequence with 5 each to see if its really ‘telling the truth’. Then pick one and work a little with seating depth. If youre gonna assume one of these groups are good, I’d look at 56.5gr and seating depth adjustments if needed.

 

[RL338]

Are you sure of your coal of 2.710” ? I found 1 horizontal picture easier to plot OCW outcome. Your rifle doesn't appear to like this combo. The little I used H4350 & 180 Accubonds was at 57.5gr.

 

[smoothie25]

I'm sorry COAL isn't correct. 2.710" is CBTO.


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[flashhole]

What distance?

Can you describe your set up?

I've done lots of OCW testing with great success. Every little thing matters to get useable results.

 

[Dr. Vette]

I also find that velocity can tell you a lot, but none are listed.

 

[smoothie25]

Distance is 100 yards. I was shooting prone off a bipod with a rear bag. All the shots felt good except one I pulled on 56.2. Didn't count that one for that group.

Unfortunately I don't have a chronograph so no velocity numbers.


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[ozarkpugs]

I couldn't help but notice 56.5 - 57.1 was in the same neighborhood with exception to a low right round , do you know which shot in the string the RT.low round was it would be interesting to see velocity on these loads .

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[smoothie25]

I don't recall the order of the shots. I'm noticing the repeat comment to velocity. Should I buy a chrono and base my load development off the avg velocities?

I'm really only looking for a MOA load. This is after all only going to be a hunting load out to 500 at the farthest. I know the groups aren't the tightest but could adjusting seating depth change the grouping? The previous load I was using for this rifle had a jump of almost .15. I'm only .02 off the lands now.


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[ozarkpugs]

I would try the formntioned loads again paying attention to where each shot goes as with out the low right they are good to go. Some people disagree but knowing which shot is the odd man out can be very telling . If you have a buddy with you let them mark shots on shadow target because if you concentrate on shots already fired you may Chase them . I actually shoot better if my group is centered several inches from my poa ( concentration spot)

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[flashhole]

100 yards distance is not long enough. 200 is minimum, 300 is better.

During OCW load development I make/use a grid target with grid lines every 2 inches and place a 2" round orange target in the upper 1/3 of the grid. The orange target is the point of aim for every shot. I like the orange because I can get a really good sight picture with the scope reticle quartering the orange circle. Makes for very consistent holds.

Lower charge/lower velocity rounds will hit lower on the target and higher charges will work up the target. Your targets cut black regardless of charge weight. A longer shooting distance will tell a much better story.

I will almost always see two nodes during an OCW test, one low, one high. As long as there are no high pressure signs I will go with the higher velocity load to extend point blank range. I also try and use powders that are not temperature sensitive like the Hodgdon Extreme line of powders.

Exact, controlled, positioning of the gun in the rest for each shot is very important to eliminate vibration variations. I use a butterfly Bulls Bag front rest and a rear bag. Never had much luck with OCW testing using a bi-pod.

 

[gbflyer]

Looks like honest shooting to me. I'm no reader of the tea leaves, but seems like any other factory gun I've ever owned. Groups are decent, but probably more accurate with factory loads unless you're a really finicky loader with lots of good equipment. Again,everyone is an expert, but I don't worry with 5 round groups for a hunting gun. Barrels are thin, factory stocks are floppy, and scopes are usually not one capable of the benchrest magnification settings.

Get yourself a chrono, work up with that 4350 to something close to max that prints 3 in 1 to 1.25, and go hunting. Probably even work at your 500 yard number if environmental conditions don't get ya. That animal you take with it won't know that the rifle doesn't put them all in one hole.

 

[.300winmag]

Shoot a ladder test at distance. Color the ogive of the bullet in each charge weight a different color. Then shoot one of each at the same aim point, look for where the loads impact the same vertically. The color on the bullet will rub off on the paper. I do this at 600 Yards, but 300 would be the minimum. If 54.4,54.6 and 54.8 all hit within 1/2 vertical of each other, I’d load 54.6 and then go to seating depth.