Ocw question

[Highvoltage]

Shot some groups today trying the ocw method for the first time looking at group impact on target vs group size. What I've noticed is the gun will group multiple 1/2" 3 shot groups but as I work though the charges, they are rarely in the same spot on the target. Is this common if you're not on the correct node?

Tikka 6.5 creed
Hornady brass
H4350
140 ballistic tip/ 143 eldx
Cci lr primer.

Top row is 143 eldx, bottom is 140 bt. Of the 2 bullets I like the last 2 groups on the bottom, they impact the target very similar. I'm thinking of shooting them again and going up 1 more charge to see if I'm in the middle of something. This was done at 100 yds, zero wind

Bottom left has a flier for sure, I've shot this charge previously and the bullet holes will sit on top of each other target to target.

 

[PddPdd]

Short answer yes. In my experience when you are in a nice wide node the adjacent groups will impact in the same area relative to the point of aim.

 

[Mikecr]

The test seems flawed.
A powder node shows up purely across a chronograph, independent of any target results.
It is a charge with a lowest MV spread from adjacent charges.

Is that useful?
It is most forgiving, NOT most accurate.
Dominant for accuracy is the barrel node. But without a barrel tuner the only thing getting both node types at once -is luck.
Fortunately, the best balance otherwise is often good enough.

 

[Highvoltage]

I'm sure my test is flawed in many ways, I'm shooting a 7lb rifle so benchrest accuracy is going to be near impossible. My main goal is to learn the ocw method and be able to understand what the target says. I've read various things on chronographs. Some say they are not needed, some say they are a must. I have a Caldwell and I'm not sure I trust what I'm reading most of the time, not to mention the times it gives me an error reading. All I know is I have reloaded always looking for group size, and unfortunately it never maintains integrity at distance. I'm just trying different methods to see what works best other than 600 yd ladders.

 

[PddPdd]

HV, Have you already done seating depth tests prior to OCW tests? If not, you may want to pick an off node powder charge for seating depth testing and optimize that first. This is something I learned from Mikecr.

 

[Idaho Lefty]

Find your rifles, Max Powder Charge at, .020 to .030, "Off Jam point" and then, start Moving Bullet in /out, .010 to .015 each time, to find the approximate, Bullet "Tune area",.. the Accuracy Node, "area" **.
IF moving Bullet into, the "Jam Point", be sure to REDUCE your Powder charge by, a 1/2 to, a full grain, to avoid Hard Bolt Lift / blown primers.
I'll Often start at, 1.5 grains under, the known Max charge and JUST "move" the Bullet back / Forth to find, the rifle's, best Accuracy ( ** then, Fine Tune, .003 each move ) if, not worried about, squeezing the last foot per second of velocity, out of, it.
You'd be surprised to know that, some Bullets "Like" it, from,.. .050 to .130 ,.. "Off Jam"

 

[Idaho Lefty]

Depending on, the Cartridge, Velocity and Powder type chosen, the AVERAGE Throat Grows from, .003 to .007 Per every, 100 Shots !!!
So "Chasing the Lands," is CONSTANT, "Work" IF, your Bullet Likes it, there ( at the Lands or, "Jammed" ).
I prefer finding, a Bullet / Load combo that, likes some, "Jump" and stays IN Tune,.. a Long Time !

 

[ShtrRdy]

Please watch this video if you haven't already done so.

Optimal Charge Weight "OCW" Load Work Up. By Ryan Furman

This will be the discussion and question thread for Ryan's new video on OCW load work up. Follow this link to down load the OCW TARGET or in a PDF HERE To watch Ryan's video and learn his process GO HERE "Optimal Charge Weight" and the acronym OCW as regards the reloading of...

www.longrangeonly.com

 

[Idaho Lefty]

To the OP,..
Group "Movement" ( POI Shift ) also comes from, too Hard of, a Cheek Weld, different Pressures on Forearm / front rest, while shooting and from NOT having, a Good Leather, Rear V Rest, properly, Filled.
You also need to see IF, your Rifle Likes "Free Recoil" or, some slight amount of Pressure, to hold it, down.
My son just found out that, his New Tikka / Proof barreled, 7 PRC, Rifle Likes two fingers lightly on side of, forearm, in front of Chamber area and reasonably Tight Shoulder pressure to, Control rifle and, group,.. well
The Rifle went from grouping, 3/4 - 1 MOA down into, the LOW 3's for 5 shots with, 180 ELD-M's T'was very frustrating for him,.. till he found this.
You're also Right about having,.. a LIGHT weight, Rifle

 

[Highvoltage]

Group "Movement" ( POI Shift ) also comes from, too Hard of, a Cheek Weld, different Pressures on Forearm / front rest, while shooting and from NOT Having a Good Leather, Rear V Rest, properly, Filled.
You also need to See IF, your Rifle Likes "Free Recoil" or, some slight amount of Pressure to hold it, down.

This may be the problem with the shift. Im shooting off front bipod, bench top is 1x6 deck boards and a rear bag. I can tell the rifle does not recoil the same every time. Sometimes it stays straight, sometimes it ends up to the left of the target.

My oal is 2.80" tikka sa mag. I'd have to look but I'm closer to .040 off with those bullets. I started at mag length with these loads and was planning on working deeper once I found a powder charge to work with. Is it powder before seating or vise versa?

 

[Idaho Lefty]

Personally, I like to do, the max. Powder Charge First, then adjust Bullet, second ( probably NO,. Wrong way )
My .270 WSM Tikka Likes .105 Jump with, 140 gr Berger Classic's at, just short of, mag length and,.
My 6.5 Creed, Tikka, likes .070 - .075 Jump with, the 143 ELD-X's and 130 gr. ELD-M's ( approx. COAL of, 2.825" to 2.830" ish )

 

[Idaho Lefty]

I am using, the New longer, M+ Tikka magazines and My load with, the 143 gr. ELD-X's is, 43.1 grains of StaBall 65 ( "Thrown" chg's ) Peterson Brass, at, a COAL of, 2.825 to 2.830 inch, F-210 M prs producing, 2,730 FPS and, 1/2 to, 5/8th's MOA Groups.
I practice on steel with, 130 gr. ELD-M's and will Hunt Deer with, the 143's

 

[Highvoltage]

Just did a search and didn't realize what the m+ mag was. This was a magazine from a 308 I had. Great info there