I have a new 308 being built by Accurate Ordnance as we speak, it should be here within a couple of weeks. I have around 100 SMK 168 Factory ammo for barrel breakin purposes. I am getting into reloading and will be reloading 175smk's with IMR-4064 powder and federal 210 primers. I am looking for the most accurate round. My plan was to measure 8-10 loaded factory shells and find the average OAL and seat my new loads to that length to start with. I was then going to start in the middle of the recommended powder load and work up 3 shot groups in .2 grain increases, up to 90% max load. Does that sound about right? Once I find the load range then I can work on seating depth.
- Thread starter Lrdchaos
- Start date
You are on the right track. Make sure to do your shooting round robin style like Dan Newberry suggests on his OCW page. Also, as long as whatever charge you are shooting, DOES NOT show any pressure signs, you should be ok to jump up and try the next higher charge. Your gun and your conditions may be different from anyone else, but when I did my workup using the OCW method for my Savage .308 using varget, Hornady match brass, cci primers and 150 gr. Hornady SST's, & 168 Amax, I ultimately ended up slightly over max published powder charges. In the end I ended up with a load that I'm very happy with and works well.Take your time, be careful paying attention to detail and you too should work your way into a load your gun likes. Happy shootin'!
It's generally suggested to do OCW / ladder tests with bullets seated "close" to the lands, even touching, to represent the highest pressure situation as you work up to define max pressure load. While on/in the lands adds to pressure, thereafter as you seat further away for longer jumps the case capacity decreases and the pressure rises again as a result. I typically use a "normal" jump for the bullet I'm using, like .020" for SMK and Hornady, or .005" for Berger. For your first round of testing, 0.2gr is a small increment, 0.5gr is adequate to define the region to focus in, but there is nothing wrong with getting it over in one round of testing with the finer cut. I have read a few reports where some pick a mid-range charge and look at seating depth first such that the smaller group sizes make the definition for OCW charge weight more clear; I think I will try that approach next time. Due to good experience now I just look at a few charges around the OBT using Quick Load as fine-tuning.
OCW actually has you load sets up to the next increment ABOVE the "max" load. Max load is not necessarily the max load for YOUR rifle. Your rifle may have a lower or higher max. So as you shoot, you check each round for pressure signs. STOP when you get pressure signs.
OCW has increments of 0.7 - 1.0% of your charge weight. It also starts 10% below your max charge.
Here is a thread with an Excel template I wrote to do the charge weight increments for OCW - http://www.snipershide.com/shooting/snipers-hide-reloading/193057-ocw-excel-template.html
Fill in the info at the top and it gives you 0.7%, 0.85% and 1.0% increments.
Most people run OCW with factory OAL, then adjust seating depth to see if you can get smaller groups.
OCW has increments of 0.7 - 1.0% of your charge weight. It also starts 10% below your max charge.
Here is a thread with an Excel template I wrote to do the charge weight increments for OCW - http://www.snipershide.com/shooting/snipers-hide-reloading/193057-ocw-excel-template.html
Fill in the info at the top and it gives you 0.7%, 0.85% and 1.0% increments.
Most people run OCW with factory OAL, then adjust seating depth to see if you can get smaller groups.
None of the specifics you mentioned match what Newberry would call for in his OCW method, and there are several steps you left out.
So, while your approach may well work, I'd have to say you don't understand the actual OCW method. The instructions are simple and can be found by googling "OCW Dan".
I've done the OCW test for three rifles this past year. A 6.5 x 47 Lapua, a .308 Win and a Cooper .222 Rem.
Done correctly it REALLY saves time and components. Read the suggestions on the site and follow them. FAR quicker and easier to find a truly accurate load by the OCW than any other method I've been able to find.
FN in MT
Done correctly it REALLY saves time and components. Read the suggestions on the site and follow them. FAR quicker and easier to find a truly accurate load by the OCW than any other method I've been able to find.
FN in MT
