Powder testing a new barrel 

Bingo

I verify it gives low SDs first before a seating test

I have no idea what you are saying?

@@justice1327 It takes work to fire form brass into a new shape. This work being done uses up energy and results in less energy available to produce velocity in the projectile and can also result in a slight increase in the case volume. So you will then see a flat spot in the chart. At the 5 minute mark in the video, John puts up a great chart showing powder charge v's Velocity. The 49.8gn charge is where this fire forming of the cartridge base is starting to take place in some cases, i.e the initial pressure failure point of the brass base area. This does not mean that the brass will completely fail at this charge but is rather simply just starting to deform into a slightly different shape. At 50.1gn charge the base area of all cases have been hammered into the new shape and velocity can then start to increase with an increase in powder charge. Brass has a creep life that can result in tight case extraction, loose primer pockets and case head separation as it gets older. But with newer brass that is shot at lower pressures it just shows up as these flat spots in the velocity graph. Cartridge brass is designed to deform to produce a gas seal. But with high pressure F-Class loads we push the brass to its safe performance limits so must understand what is happening in order to get the best accuracy and life out of it.

I’m sure there is but I honestly don’t know what it is other than it has to do with timing the harmonics somehow.

My pleasure and thanks for the the comments.

It’s called ChronoPlotter. Here’s a video I did on it. How to plot powder velocity test data fast and easy with Chronoplotter! ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-KjujkN7b7lk.html

There's several programs out there. I'll work on doing a video to show how they work.

Awesome thanks John!!!

Yeah I totally get it and all I can say is that it’s working for me right now but I do agree with some of your assessments. I think we have always chalked it up that each barrel has a slightly different harmonic to it which is why they all tune a little differently but in the end they are almost always all in the same range with all things being equal.

@@FClassJohn I dont know if it comes from the barrel or the powders that I use

It’s all good. I’ll definitely let you know if 49.8 doesn’t pan out. 🙂

He still has the seating depth steps to conduct... this will influence the SD

The load ladder node is to find a node where ES less sensitive to loading differences. The optimum point should be a combination of both, spread and velocity slope.

That’s the inertial trigger for the Labradar to ensure all the shots get picked up.

Steve, It uses recoil instead of sound to trigger the lab radar.

No problem. Glad you liked it.

20-30 thousand and farther from the lands no, closer you get its gets more picky since it increase pressures and velocities.

I used to put a lot more importance on ES than I do now. As long as the ES or SD isn't horrible I will always go with what prints better on paper. That's not to say I will accept bad ES but I trust paper more than numbers all things being equal.

@@FClassJohn thanks again! So do you take the centre of that node and then test seating depth from here, or do you try groups at a consistent seating depth and vary charges across the node range to find best group pattern, ie power charges going up by 0.1gr before doing seating depth? I assume you take the centre charge and test for seating depth now?

By looking at loading manuals or powder manufacturer websites. That is always going to be the safest place to start.

Usually a couple hundred or when the barrel has stopped speeding up.

All things being equal the nodes are fairly repeatable.

Yes it usually does. The bullet will depart the case and leave the barrel in a time that coincides with the harmonics of the pwdr/primer combination

Your basically looking for the most consistent velocity,

I honestly don't have any experience with them. They seem cool but for what they cost I don't think it's practical for F-Class since I do through 4-6 barrels a year. I know someone using one for ELR and they like it but I haven't followed up with them in a while on it.

@@FClassJohn they claim the barrel runs a lot cooler, extending the barrel life a lot and, harmonically speaking, has a wide node due to the structuring. With you using so many barrels and always trying to stay in node, I thought something like this may be worth it. Full disclaimer, I've pulled the trigger and mine should be here soon.

@@JacobTerherst Yeah I've heard the claims on cooler running and obviously that would be cool, but here's the thing for what I do. Some barrels naturally shoot better than others. I often spin up a few barrels at a time, develop two or three and then put aside the top shooter for high level matches and so on. I can buy three Brux barrels for the price of one structured. So what happens if you get a good shooter, not a great shooter? For me it'd be a waste of money in that case. Like I said, I think for some disciplines they have a strong future but I'll honestly say I'm probably not gonna be the guinea pig for F-class with one. I know there are other factors too like weight and diameter which could affect making weight or having to modify a stock to accommodate it. I'm really curious to hear what you thing when you get it and your thoughts.

I have the same question. I'd love to be able to use less expensive bullets for this test and save the expensive stuff for matches. But not if it will mess up the velocity node. Loading for XTC service rifle is much easier than this.

Because the group size is irrelevant at this point because seating depth will control the group, but you have to be in a stable node to maintain the accuracy. Finding the node is a velocity thing, not a group size or accuracy thing at this point.

On top of what John said.... I've seen horrible ES groups look great on paper... at 100 yards. When you're shooting at 600-1000 yards, how much elevation is each 1fps worth? Quite a bit.

By no means am I saying that the method is flawed. I shoot on paper to validate. Seeing a flat spot in velocity should result in a flat spot in the groups (horizontally speaking). I guess I like to see the validation rather than just shooting steel. It also gives me a bit of insight on where to go from there.

@@ponderosaarms7996 the thing is you could have a banger group at 100 and an ES of 30. Take that out to 1000 and that’s a big variation. Just don’t want to get muddled up by group sizes at this point since It’s irrelevant and will all settle down when setting depth is done.

Blue line is average, red triangle is Median. I only track velocity, not SD or ES.

@@FClassJohn Thanks for the response, John. I'll have another look at my data before I load for seating depths. From your experience, have you noticed a change in SD & ES at different seating depths?

@@bird_tees Honestly not much but I also run really light neck tension. I have regularly shot a seating test from .009 up to .033" and still kept an ES of 20ish.

@@FClassJohn Sounds good. Thanks John!

@@FClassJohn So going from that response and your technique here, you dont chase low sd/es numbers. Just a velocity node, followed by grouping via setting depth?

Go to the "competition" section on the accurate shooter forum

Yep, what Aaron said. That's what I always recommend to people as well.