I guess 2 out of three is as good as it gets

[Alderman]

Shot these rounds this afternoon. Ruger Hawkeye 280.
The Partition load has gone under 1" for two straight and wiifm be the hunt load for this rifle this year.
Although I'm satisfied with these I would like to someday slop that third one into the hole with the other two.

 

[Darkhorse]

Shot these rounds this afternoon. Ruger Hawkeye 280.
The Partition load has gone under 1" for two straight and wiifm be the hunt load for this rifle this year.
Although I'm satisfied with these I would like to someday slop that third one into the hole with the other two.

I don't think your quite "on" the node. I'd vary the seating depth by .005 and shoot a few more groups. I say .005 instead of .010 because it looks like you are very close. I think getting that 3rd shot into the group is very doable from where your at.
My records show small changes in seating depth has more effect than small changes in powder. I'd stick with 51.5 load of IMR 4350 if this is going to be your hunting load.

 

[FOTIS]

Target analysis.

Bedding
optics
hot barrel
seating depth.

 

[Oldtrader3]

I use 58.0 grains of IMR 7828 SSC with 160 Partitions, Fed 215 MM primer and get groups at around 3/4 MOA to 300 yards and velocities close to 3010 fps.

 

[rodell]

Seat them deeper. Two in, one out begs for it.

 

[JD338]

As already mentioned, you need to seat the bullet deeper. A 1/4 turn on the seating plunger, which is about .005" should walk the third one into the group.

JD338

 

[OU812]

Seat them deeper. Two in, one out begs for it.

+1

 

[Alderman]

Will try going deeper next chance I get. If that works that is a cheap fix. Thanks.

 

[Jgraider]

Target analysis.

Bedding
optics
hot barrel
seating depth.

I am going to agree with Fotis on this one. I've had a couple of rifles that did this, and tidying up the bedding fixed it both times. That would be my guess anyway.

 

[Alderman]

Is the bedding issue created from pressure on the barrel or the action moving in the stock? These two groups were shot back to back starting with a cool barrel.
While I didn't rush the shots, the barrel was getting warm after six shots.

 

[Darkhorse]

It can be either one, if the barrel is not free floating then I would say that is likely the culprit. As the barrel heats it moves, some companys barrel steel moves more than others, as it moves it presses against the stock changing the harmonics. Or in some cases actually moving (bending) the barrel. During those years in the gunsafe the wood in the forend of my M700 warped and actually wore the blueing off in the contact point just sitting there.
I glass bedded the receiver and the recoil lug, while free floating the barrel of my old M700 which takes those problems out of the equation. So now my fliers are either caused by me or my handloads, which is something I can improve on.

 

[Oldtrader3]

Your loads are too light to group well!

 

[ElmerThud]

OT3 may well be on the right track - the Hodgdon site does not show a load for this bullet weight with IMR4350.
But does for H4350.
Steves Pages lists 42.1 - 55.5 with IMR4350 for the weight of bullet you use.

Of course the other guys may well be right and a combination of factors are giving rise to the problem. Certainly barrel harmonics change as heat in them rises, particularly with sporting barrels.

If all appears tight and correct with metal to stock & no issue with scope, I'd definitely look at the load first starting together with case prep to ensure as little variation as possible and correct case resizing to headspace.
Best of luck sorting the problem out. ATB

 

[Darkhorse]

51.5 is the max load Nosler shows for the 150 gr. PT. With IMR 4350. While an older IMR guide shows 55 grs. IMR 4350 with the 150 SP Corlokt.
In some cases different bullets have longer bearing surfaces which will increase pressure, so I would tend to follow the bullet Manufacturers guide to start off with. A 3.5 grain increase can be a bunch.
That said; Many rifles shoot best at the higher pressures generated by max or near max loads. I myself might try to work a little hotter load than 51.5 grs. but I only work pressures by measuring case head expansion first with a set of .0001 micrometers.
Before I did anything I'd seat a few loads deeper by .005 and see what happens. You might be surprised.

 

[Oldtrader3]

I have owned a Model 70 and a Browning A-Bolt II .280. I shot both of them for over 15 years with a 160 Partition and 58.0 Grains of IMR 7828 SSC. I even used a Fed 215 primer on some of these loads and never had any pressure signs. I know several people who use the same load. I also loaded with 55.0 grains of IMR 4350 and got only 2720 fps. This caliber was introduced for the 742 Remington which is a semi auto and can not handle over 50 KSI.

 

[ElmerThud]

Have to admit I'm not a .280Rem shooter, but with my .25-06 I'm running a full 2grns more than the Nosler data with the 110gn AB bullet. But 1gn less (max) than the data in the Lee manual for the 100gn bullet.
That said my COAL is rather longer than the listed data too, but there is absolutely no pressure issue at all. I have a 22" barrel and chrono at 3130fps MV.
The results are extremely satisfactory.

My point is, data is a guide and the user works his load to where he finds the most accurate while retaining a 'safe' load. So, changing the cartridge data spec a little to personalise the round to the rifle utilising 'trial & error' methods is not unusual. May not be SAAMI, but still nevertheless may remain safe and solve the problem.
It's not necessarily the rifle, simply more work on the load required. Can be fun as well as frustrating! ATB