Powder Load Development - 284 Win vs Vihtavuori N165 

You're very welcome!

You can't. Even when shooting round-robin, the internal state of the barrel is ever changing. With that in mind, a dirty barrel is going to change less over a number of rounds than a dead clean one. Proper fouling prior to testing is the key to the best results in my experience.

In my experience, yes. From 7-270 WSM to the little 223 rem, it usually finds its way in there.

@@winninginthewind why have I never heard this before? Thanks for sharing your knowledge. Your saving me time, money, and headaches.

I personally find it hard to even hold sub 1/3" at 100 in the prone with a bipod and rear bag so would be nice to see contrasting situations and see how your results vary

Ask him - he started it.

I do rough testing n .006" increments. I could go a little bigger, but I can cover quite a bit of ground very quickly at .006". Remember that if the first two aren't close together, it's time to move on.

@@winninginthewind what would you call bigger? I tried a few 0.5mm (0.02in) that seem way to big now. A 71mm oal works with my Custom Comps however I'm working up a scenar now. Would going 0.25mm / 0.01in increments be too big. As I have very little idea where these would work. And then I'd go from 70 - 72 mm oal which would be 24 rounds for seating depth. And a few more for fine tuning. I've chosen my load based on where GRT says I should be on a node.

I don't do anything in steps larger than .010, too easy to completely miss a good spot.

Yes, no, maybe. I'm allowing room to grow for temp in two different ways. The first is not going above max pressure, for safety reasons, and the second is to ensure I don't blow through the top of the node window. Remember, there is that upper shelf of the node identified in the video. I also use a reasonable expectation of temperature based velocity change that may or may not be accurate for any given powder. That is where extensive experience with a powder type comes in, and I don't have that kind of experience with this powder. Staying conservative until you know a powder is the best plan I have.

I use Excel for just about all of my analysis.

Yes I do! Video coming soon!

Yes I have, and it didn't turn out well.

From .010 into the lands, I work both directions. I really expect that I'm already there with this one.

Unfortunately, no.

Glad it was helpful!

I did that solely for the purpose of making a video and barrel warming. If I were doing this for a competition load with an already warm barrel, I would have fired one and moved on.

Yes, in that shooter skill gets mixed in more broadly with a bipod. In that case, a little interpretation is in order. It may not print all shots into 1/4MOA on the paper, but the one out is known or suspected to be shooter error - I consider that as good as one is going to get.

For me, competitive velocity is a situation where I limit the advantage I give to my competitors with my bullet and velocity decisions. Every bullet has a different minimum velocity to be competitive at the highest levels. The other thing to consider is what are your competitors shooting? Not that one person that makes a million, zillion fps, but the people that win matches year after year.

@@winninginthewind thank you sir. That makes sense.

Not intentionally at a match.

@@winninginthewind how about a 20 shot string outside a match?

I'd do it toward the low end of the charge range. We want to be safe, and seating depth does affect pressure.

Use a low, starting book charge for seating testing. I test in .005" increments because the seating depth nodes can be narrow, especially for thin profile barrels. .010" is fine for heavy barrels. Take the best charge and use that in the powder charge tests. I've found that the original, optimal seating depth doesn't change more than .005" when you go to fine tune after powder charge

@@winninginthewind thank you, I have been reloading for a very long time and never did bullet seating depth test until I started watching RU-vid videos by you, Erik Cortinas and others. The info you and others share is amazing and I appreciate it Thank you again.

That depends on the barrel. In an F-open rifle with a barrel that resembles the axle from a truck, I am only waiting 10-15 seconds between shots. With a lighter barrel, I slow down a lot to keep the barrel temperature down.

@@winninginthewind This is interesting. Would be interested in further understanding the actual temperature effects and how they materialize. Ive thought about this quite a bit and would be interested in feedback on some hypothesis. To start, framing the problem as 2 classes of problems: the first is variation in velocity and the other is variation in POI. For the first (velocity variation), I can see two factors that could influence. First is pretty straight forward being the temperature of the powder from the chamber heat. The other is inner diameter of the barrel changing as a result of CTE; could a smaller or larger diameter effect resistance/friction leading to pressure/velocity changes? The other being POI changes would appear to be a product of two potential CTE effects. The first is asymmetric stress from material removal operations causing asymmetric expansions (is stress relieving a barrel post machining a thing?). The other hypothesis would be ID of the barrel changes having effects predicted by optimal barrel time theory (ie large ID of barrel causing larger group size). With all that, can you kill any of these ideas directly or expand on/point me in the direction where I can learn more about these subjects?

Glad you liked it!