280AI range results

[Evilsports]

Well this load has been nothing if not a wealth of learning for me. Just when it feels like I'm onto a load, a new variable pops up and sets me back a bit.

Figured I had things dialled in fairly well as far as charge weight goes. Went to test at the range yesterday morning and could not hit a group again. Noticed that with the exact same weight (58.6gr) of H4831 I was getting muzzle velocities averaging 80fps higher than last weekend.

The only difference was that I had previously been using up powder and primers that were a decade old. These new supplies were obviously running higher pressures than those old ones.

I came back home and loaded up some lower test weights (57-58) and my groups tightened up to right around a minute back at the range. My velocities were still higher than my tightest groups from the previous weekend, so this morning I'll load some increments from 55-57gr and see if they tighten up further.

 

[Deputy819]

How many rounds down the pipe thus far?

 

[Evilsports]

How many rounds down the pipe thus far?

Man, I'm embarrassed to say but it's pushing 150 rounds with this combo. I'd have pulled the pin on it a while ago but in a moment of feeling close to having it dialed in I bought more powder and bullets. Now I'm committed!

 

[Deputy819]

getting muzzle velocities averaging 80fps higher than last weekend.

came back home and loaded up some lower test weights (57-58) and my groups tightened up to right around a minute back at the range. My velocities were still higher than my tightest groups from the previous weekend,

Interesting. What Chrony are you using, by the way?

 

[Evilsports]

Interesting. What Chrony are you using, by the way?

One of these guys:

ProChrono Pal - Competition Electronics

Instructions [PDF] | Accessories

www.competitionelectronics.com

 

[Evilsports]

So my group's tightened up with the lower charges, I tested 56.0 up to 57.2. Best group was 0.571 at 100 yd, all the rest sub moa.

I don't know if I'm maybe getting too fussy, but even the half inch group looks like it's a mile wide on paper. Am I stupid to expect more than this? Factory 140 grain Nosler accubond groups were touching with this gun.

I'm shooting full lead sled rest, 2 lb trigger and it's surprising me with the break every time. I'm not ruling out possible form factors, but I feel like I'm not introducing any torque into the equation.

I'll post up my data once I get home.

I have to figure out what's left to refine with this load.

 

[Deputy819]

So my group's tightened up with the lower charges, I tested 56.0 up to 57.2. Best group was 0.571 at 100 yd, all the rest sub moa.

What's your velocity using the 168's with this low of a charge weight? 56-57 gr H4831SC seems rather 'anemic'.

I don't know if I'm maybe getting too fussy, but even the half inch group looks like it's a mile wide on paper. Am I stupid to expect more than this?

No. Are you able to shoot it beyond 100 yards to see what it (and you) can do?

I'm shooting full lead sled rest,

You'll get varying opinions on this, but I'd ditch the lead sled if I were you and let the rifle recoil freely/naturally.

 

[Evilsports]

What's your velocity using the 168's with this low of a charge weight? 56-57 gr H4831SC seems rather 'anemic'.

No. Are you able to shoot it beyond 100 yards to see what it (and you) can do?

You'll get varying opinions on this, but I'd ditch the lead sled if I were you and let the rifle recoil freely/naturally.

Attached today's velocities. This thing just seems to start falling apart anywhere much over 2800fps. With the old jug of h4831 and old primers I was using about a grain more to get the same speeds.

I just grabbed some CCI BR2's. Am going to try a non mag primer. I'll stretch it out at a longer lane as well and see how it behaves.

 

[Deputy819]

56.2-56.6 looks pretty stable in terms of velocity. If it groups well then 'run with it'. There's another node in the 2800's, though….I'd try it (components permitting) OUT of the Lead Sled and see what happens.

 

[Evilsports]

56.2-56.6 looks pretty stable in terms of velocity. If it groups well then 'run with it'. There's another node in the 2800's, though….I'd try it (components permitting) OUT of the Lead Sled and see what happens.

The only reason I'm still messing with these and not working up a bullet with a tangent is because I over committed to a lot of components... Back when I was a little more optimistic.

 

[Evilsports]

Waiting for the range to open.... Don't judge me Deputy.

 

[Evilsports]

Taking one last kick at these. Going to try a few lightly touching lands... It's the only thing I haven't tried regarding seat depth. (Thought I had a few weeks ago but accurate chamber measurements showed me that I was still .012" jumping...).

Hunting season is less than 3 weeks away so if I don't see promise this morning I'll revert to a 7mm Rem-Mag with a known factory load for hunting. I can reconvene this .280/VLD experiment after hunting.

Getting close enough to hunting season that I really need to be able to stop thinking about load data and focus more on the other logistics of my hunt.

 

[Evilsports]

Went to replace the battery in my Chrono to rule that out. Found this... Wondering if it might have had something to do with some nonsensical velocities over the last few weeks?

 

[Deputy819]

Don't judge me Deputy.

Wouldn't ever do that, bro.

Went to replace the battery in my Chrono to rule that out. Found this... Wondering if it might have had something to do with some nonsensical velocities over the last few weeks?

Ain't this fun?!?