Home Forums Reloading Big Game Rifles So I did the OCW thing with my T-3X

and I did not get a definite trend or movement from one group to the next. Not sure what it's telling me.

Tikka T-3X Lite SS, 243 win
95 gr Nosler BT
Loaded RL-23 with the following 4 shot groups:

43.5 gr - 1.3" group, baseline center group used for comparison to the following loads (avg vel = 2904 fps)
44.0 gr - 0.8" group, center is within 1/4" up and left of baseline (avg vel = 2936 fps)
44.5 gr - 0.97" group. center is within 1/4" up and right of baseline (avg vel = 2956 fps)
45.0 gr - 1.25" group, center is level and 1/4" left of baseline (avg vel = 2996 fps)
45.5 gr - 0.59" group, center is level and 1/4" left of baseline (avg vel = 3009 fps)

The instructions say don't get too caught up in individual group size. I think it's just telling me that i'm in a good zone with this powder/load combo and I should just focus on groups 2, 3 and 5. What do you say? I've used this method before with my X-Bolt in 7mm wsm and had good definitive results which absolutely worked as expected.

Thanks

bludog

Rather than 2 and 3, I'd look at 44.2 grains.

I know .2 grains can make a lot of difference in groups as I just witnessed it when I loaded some 7-08 loads..
What are you looking at when you suggested the 44.2 instead of 2 or 3.
Are you looking at the velocity increase compared to 44.5 and the other velocity increases?

Yeah, tell me why Mathman, I appreciate your experience and respect your opinion.

Actually, after looking at it from a fresh perspective, I'll try the 44.2 gr load. Thanks Mathman, I'll let everyone know how it works. A good consistent load is the goal for sure. All velocities were within an acceptable window IMO.

bludog

It's a semi wild assed guess.

In 308'ish cartridges the "good spots" are often around 3% increments apart, with "bad spots" at the 1.5% increments. Assuming your 45.5 grain group wasn't a fluke, coming down 3% puts you at 45.5/1.03 = 44.17 or so. So i rounded to 44.2. Pretty fancy, right?

I'm not so sure how well this relates to the smaller necked 243 with a slower than 308 type powder.

It might be a guess but I'd say it's a damn good guess and it jives with the numbers. 😁

I'd go with 44.2 also and I'd try 45.6 as well as it appears 44.5 was getting very close to the second node. Being a tikka I'd expect a possible .3 ish group or maybe even better




Trystan

I'm curious to see how mathman's WAG works out.

I'll probably give it a go Friday.

What does OCW Mean?

You work up loads, like people's been doing since the 1940's except you shot them round robin instead of all of a given powder charge at one time, and give it a stupid acronym.

Like OCD but not as much disorder

I think its Optimum Charge Weight. I never really saw the need to go full OCD on OCW.

Well, I must give Mathman credit - shot a five shot group with 44.2 gr of RL-23 per his WAG recommendations.

First 3 were 0.42" in almost a perfect little equilateral triangle. Next one nearly doubled the group size to 0.82". Last one landed almost on top of the initial shot resulting in a best 4 of 0.52" and a total five shot group of 0.82". I'll take that for deer hunting any day.

I think the supposed benefit is to attempt to give you a way to evaluate your results to give you more repeatability, i.e., which loads to focus on. It gives me a little structure once I start getting some decent groupings with a particular rifle.

I'll try to post target pics if I can figure how to download from phone to laptop.

Thanks Mathman for your input.

You're welcome, but don't give me too much credit.

Is RL-23 a small kernel powder?

More on the OCW for the uninitiated.

I have more "faith" in OCW than the Ladder method myself.

http://optimalchargeweight.embarqspace.com/

Mathman,

RL-23 is about like RL-17, or H-4350 - smaller kernel than RL-22 or IMR-4831. I'd consider it a smaller kernel powder. Not exactly sure what the criteria is for that moniker.

bludog

No precise criterion. I was thinking about reasonable metering characteristics since I prefer to throw charges when the load allows.

I use OCW also at 200 yds instead of 100 using two different powders. I pick the load that has the least vertical stringing along with the powder that produced best overall groups and move straight to 500. At 500 I fine tune until vertical string is gone adjusting seating depth to eliminate horizontal problems.

If the load doesn't show promise up front with two different powder I might try other powders but generally move to a different bullet and start over. This is all assuming I have eliminated any bedding or excessive run out issues with reloaded ammo. The nice thing about tikka's is generally bedding is never the issue.

When a great load is found than I move on to testing for temp sensitivity. Sometimes your ok and sometimes you have to start over. If you done some research first generally youve picked a powder where success has been found by a number of other handloaders already. Or sometimes as is the case with my 6.5 swede RL 26 load I had to test for temp sensitivity because there wasn't any data out there yet. The load with a 147 eld proved to be within 6 fps from 62° Fahrenheit down to 5° which is in the temp ranges I generally hunt. That's a good load that will work on any day of the week not just the good days



Trystan