280 - Any potential here??

[M7025-06]

Ran some more test loads with the 280 this morning with 139 gr. Interlock-BT's & IMR-4451 / 55.5 gr., 56.0 gr., & 56.5 gr. The bullet was seated 0.029'' off the lands for all groups. It was a really nice morning...45* with almost no wind. None of the loads showed any signs of pressure.

A). 55.5 gr clocked at 2978 fps / 2.52'' vertical spread at 218 yds. (3 shot group)

B). 56.0 gr clocked at 3021 fps / 2.52'' triangle at 218 yds. *see pic* (3 shot group)

C). 56.5 gr clocked at 3040 fps / 2.72'' horizontal spread at 218 yds. (3 shot group)

I'm really happy with the velocities I'm seeing, but obviously I'd like to see some tighter groups. My thought is to take load B and play with the seating depth to see if things tighten up or adjust the powder charge 0.2 or 0.3 gr up & down and see if that improves things.

Do any of you guys see any potential with this load or do you think I'm wasting my time? Any thoughts or advice is welcome.

 

[Horsethief]

Working on the seating depths or the powder charge is a way to go as long as you only change one variable at a time. The best load with your 139gn bullets may work even better with a 140gn boat tail bullet. My 280 did better with H-4350, RL-19 and Superformance than with anything I tried with H-4831 using 140 and 150 grain bullets. However, 154gn SSTs did very well with the H-4831. Slightly longer bullet with the same general powder burn speed can be a major difference. Keep working, and keep the barrel temp from getting hot.

 

[Dwh7271]

Not sure it'll help but with a cup and core like the interlock I'd lengthen them a bit. Scoot em a little closer to the lands in increments and you might be pretty happy.

 

[DrMike]

I've taken scores of mulies and whitetails with a Model 70 chambered in .280 Remington. I built my loads around the 139 grain Hornady Interlock. It took about 200 rounds to get the rifle broken in as I wanted. Velocities initially were low, coppering in the bore was terrible and accuracy was a disappointment. Now, it shoots to potential with 0.25 MOA with a variety of 139/140 grain bullets. Dewey's suggestion to load closer to the lands mirrors my experience. Most of my rounds are seated between 0.010 and 0.020 inches off the lands.

 

[M7025-06]

Thanks for the replies fellas. I'm definitely going to try messing with the seating depth.

This might be a dumb question...since all 3 groups were at about the same spread, would you concentrate on the powder charge with the highest velocity or tweek all 3. The reason I ask is I'm running short on time before deer season opens and I can only get to the range about every-other Sunday, which means I've only got 2 maybe 3 trips left before opener. I know you don't want to rush this stuff like this, but I need to figure out how to the most efficient with the time I have. If I can shrink one of these loads down to under 2''...I'll be a happy man.

 

[Darkhorse]

I pick the load I want to hunt with that gives me the desired velocity and start tweaking the seating depth from there. Don't change anything else at this point. By changing the seating depth you should find a node along the way. In my .300 all bullets are seated right at .100" off the lands and that rifle will shoot under .250" with hunting loads. In my M700 I have loads from .010 to .045 off the lands that shoot under .500"
If I was only after accuracy I would do things different but what I'm after for hunting is velocity plus acceptable accuracy.
When dialing in a BOSS tuner you pick a load then start tuning the barrel till you find a node. Changing seating depth does the same thing as dialing in a BOSS, you are looking for a node.

 

[Dwh7271]

Those really aren't bad for right at 220 yds.
I'd load at .020, .015, and .01 off the lands with that 56 gr load and see if they tighten. If you're tighter at .015 but no better at .01 then next trip, split the difference with a couple and you should have what you want.

 

[Horsethief]

I pick the load I want to hunt with that gives me the desired velocity and start tweaking the seating depth from there. Don't change anything else at this point. By changing the seating depth you should find a node along the way. In my .300 all bullets are seated right at .100" off the lands and that rifle will shoot under .250" with hunting loads. In my M700 I have loads from .010 to .045 off the lands that shoot under .500"
If I was only after accuracy I would do things different but what I'm after for hunting is velocity plus acceptable accuracy.
When dialing in a BOSS tuner you pick a load then start tuning the barrel till you find a node. Changing seating depth does the same thing as dialing in a BOSS, you are looking for a node.

Yup. Acceptable accuracy at the range you expect to have to shoot from should be your goal. Hunting accuracy = minute of deer. Keep us posted.

 

[M7025-06]

You guys hit the nail on the head. Shot 3 groups this morning at 0.020", 0.015, & 0.010" off the lands and I think I found a winner at 0.015" off.

Sent from my HTC6535LVW using Tapatalk

 

[DrMike]

Oh, yeah, that'll do. You're there!