TPM - Intro to Precision Rifle Reloading - Initial Load Development - Dan Newberry's OCW Method 

You're very welcome! Thank you. -TPM

Many thanks!

Absolutely. Dan and Bryan Litz are an absolutely wealth of knowledge and have contributed a massive amount to this sport. I’ve interacted with both over email and on forums and was always amazed at how much they knew and how helpful they were. Highly recommend reading Litz’s book, Applied Ballistics.

Thanks for the sub! I appreciate it. Let me know if you have any topics you would like to see covered.

I absolutely agree with you on the 3 vs 5 shots. The only benefit you get from 5 shots is a little better sample size for more accurate chrono data, although even 5 shots isn’t enough in my opinion to get a “hard” velocity average and ES. I noticed on this target that the 5 shot groups almost muddied the waters as far as interpreting the results of the test. I’ll be sticking to 3 from now on.

Glad it was helpful!

Absolutely. I use a tool made by Sinclair to find the point where the bullet profile is just touching the lands and back off .020". I chose .020" a long time ago because I had good results there and you can potentially run into premature pressure issues if you seat at the lands, or into the lands. I just posted a video detailing the next step after the OCW test on exactly what you mentioned, an incremental seating depth test to fine tune accuracy. You make a great point about separating the brass from over max pressure loads. I try and stop well before it gets to that point and usually just have a mildly sticky bolt of near flat primer. I'll set those cases aside and measure the web diameter and compare it to other cases. If its larger, has a significant ejector mark or any blow by in the primer pocket, it gets smashed and trashed.

That’s a great question. The beauty of the OCW test is if done properly, you locate a powder charge that will allow for some degree of variance in pressure from changing conditions. Start out with a good, temperature stable powder and make sure you’re reloads are as good as can be. Record the muzzle velocity, weather conditions, and your overall findings. When the weather warms up, your cartridge pressure may go up a slight amount which you can revisit at that time by running a few rounds over the chronograph. I’ve done this several times and never had any issue. My only advice, make sure when you are doing your testing, try and locate the pressure threshold for your particular rifle and make sure your final load isn’t right up against that. Often times when you are conducting the OCW test, you’ll find a couple of “accuracy nodes,” through the range of powder charges you’re testing and sometimes there is a high one that is right up at the max pressure range for your rifle. I’ve always avoided this node and found luck at the next node down. Velocity is always second for me, accuracy and consistency take precedence. Good luck! -TPM

Dealing with this a lot in Canada this year been shooting at -30C and its been a nightmare for loads I worked up at +30 in the summer. You will find that in addition to throwing you out of your velocity node, the weather may get your barrel so cold that it will affect your shot as well regardless of the load. Also another thing that screwed me up pretty badly was going to load some "winter" rounds and having the bipod skip off the frozen ground during load development.. lots of wasted time and components until i figured that one out.

Hello neighbor. You guys sure have been dealing with a lot up there. I usually end up doing most of my load development in the winter when its usually somewhere between -10 and 35 degrees F. I hunt down south in the fall where it has been as hot as 110 F. Even with that temp. swing, I stay in my accuracy node and only have a slight increase in velocity. What powder are you using? The Hodgdon Extreme powders have proven to be very temp. stable. I've used the Reloader powders and some Vhitavouri stuff, but I always go back to the Hodgdon Extreme powders.

@@triggeredprecisionmachinellc Put the loaded rifle in your deepfreeze for half a day and see how that frozen barrel affects it. You can run the same test with it unloaded and see which affects it more (and how). Temp sensitive powder does help, but doesn't do anything about the barrel itself freezing. There have been coyote hunts when I sit and watch the end of the barrel turn white with frost and slowly climb down the barrel all the way to the action! I found there was more of a difference with a frozen barrel than with frozen ammo, though the combination of both can't help.

Very interesting..... You have me intrigued, I have to do that now. That sounds like an interesting test indeed. Thanks!

Thank you, sir!

The idea is if you spread the effect of barrel fouling out through the test. So if you shot your OCW test by just shooting all the different charge weights as groups, meaning all three loads from powder charge one, all three from #2, and so on.... by the time you got to your final powder charge, your barrel would have all the previous rounds on it and potentially have some effect on how it shoots. Also heat build up. I do my best to allow the barrel to cool between shots, but it really isn't feasible to let it cool to the exact same temp every time... this could take a long time depending on the shooting conditions. So you are spreading that effect out evenly among the test.

Yup! Strapping the magneto speed onto the barrel absolutely will change the harmonics and POI. I reserve the Magnetospeed for velocity confirmation in the field or at the range after I get all my load development done. Its a great tool, but like you said, you don't want to have it on during load development or when you're checking zero. Awesome point to bring up, by the way.

@@triggeredprecisionmachinellc A point taken Shawn on the magneto speed. I tried my first test with it strapped on. Will redo and leave off.

Let me know what you find!

Cheers, do you break position after each shot? That is a great vid thanks

100 yards is a good distance. Shooting further just increases the potential for environmental factors (wind) to change the results you see and make the test invalid.

What would you recommend I start at for a 6 creed with 105 Berger target. I am trying to load some tonight for the first time

I shoot a 115 DTAC in my 6CM so my load is going to be a bit off from where you need to be. If you have H4350, I would experiment in the 40 Gr - 44 Gr range. Work up slowly and look for pressure signs. Start .020" off the lands.

@@grantedwards3262 the last time I did this for the 6mm Creedmoor and Berger 105 gr Hybrid I spanned 39.5 to 42.5 grain. That was with H-4350 in Lapua brass.

Awesome, thanks Todd! I need to experiment with the 105 Bergers. I ran those in a 243 Win for a while. Great shooting little bullets.