No POI change during load development.

[DoneNOut]

I got a rough idea of distance to the lands, will have to watch more videos on it and get it more accurate. For these I went for an OAL of 3.346 which JUST fits in the magazine, being a hopeful hunting round that was priority number one there, but I will still adjust both ways to note any changes.

Then you are in luck. Start mag length and seat deeper to see if anything changes! Don't worry about DTL!

 

[Philward]

What's this mysterious h4381 powder ?

 

[RB II]

Country boy chronometer..........
Once you settle on "the" load, you can verify actual speed by shooting a known distance target, like 400 yds. Measure the drop from the POA to POI. Adjust the velocity in your ballistics calculator to match that amount of "drop" at that distance using various velocities until it matches. Will be VERY close to the chrono average.

 

[keen.on.it]

What's this mysterious h4381 powder ?

Hahahahaha mysterious indeed! I was questioning it as I was writing it on there too, definitely going to keep writing it that way from here on out. Too funny!

 

[Tiny Tim]

I will be posting on some Facebook groups in my area to find someone nice enough to take me out with their chronograph for the time being, shouldn't have an issue I would imagine. No pressure signs but it sure did seem like it was getting pretty spicy starting at 53.5gr. 54gr kicked some good, not sure I've had my 270 kick like that, but I might just have been overthinking it being the top of my powder test on my first load?

Chronograph will help, and learn to read pressure signs. When I started load development with a 124gr HH in 300 RUM, the brake made it feel as if the rifle was pulling away from my shoulder. At a certain point, it came alive and the rifle behaved differently. I was no where near maximum, but felt a significant difference in the way the rifle behaved. Good observation about felt recoil. Shows your observant and aware of the entire shot process.

 

[Taylorbok]

for what it's worth that first group (54gr) does appear to have a slightly different POI than the others.

 

[keen.on.it]

Chronograph will help, and learn to read pressure signs. When I started load development with a 124gr HH in 300 RUM, the brake made it feel as if the rifle was pulling away from my shoulder. At a certain point, it came alive and the rifle behaved differently. I was no where near maximum, but felt a significant difference in the way the rifle behaved. Good observation about felt recoil. Shows your observant and aware of the entire shot process.

I was taking it real slow, and being ultra cautious for my first time, the first shot was probably the most stressful shot I've ever taken haha. I didn't want to go right to max for my first time loading and I'm glad I didn't.
Not sure I would have shot them anyways even though there was no obvious pressure signs at 54gr but yeah, the rifle bounced in a way it hadn't with any of the other loads, or factory ammo, really noticed on the final shot.

 

[Pdyson]

I couldn't help but notice you are using BR2s. These are almost un obtainable. When they do pop up they sell for almost double what they are worth. I hope you can get more, hunting season is right around the corner.

 

[keen.on.it]

I couldn't help but notice you are using BR2s. These are almost un obtainable. When they do pop up they sell for almost double what they are worth. I hope you can get more, hunting season is right around the corner.

A small local shop just got them in stock, only selling 100 per customer, my dads going to get another 100 tomorrow as we'll be loading for his 270 as well.

 

[kfreeze]

Here is an example of normal POI shift in a ladder test with a 280ai, rl23, and 180 bergers at 200 yds. This is from starting load until the case showed pressure. Never mind the bad group above the mirage was really bad after I shot the ladder and I loaded 5 rounds to try a group. Haha

 

[keen.on.it]

Country boy chronometer..........
Once you settle on "the" load, you can verify actual speed by shooting a known distance target, like 400 yds. Measure the drop from the POA to POI. Adjust the velocity in your ballistics calculator to match that amount of "drop" at that distance using various velocities until it matches. Will be VERY close to the chrono average.

Did this today at 400 yards, but will have to do it again as I was not 100% confident in my top-of-the-sonotube aiming point, but about 33" of drop would put me at roughly 2600fps. Sure was a country boy chronometer! Haha