280 Ackley Imp with a Tuner

Jackie, one of the things I have found with a slightly different round -- one very close to a .308 Norma magnum -- is that with Reloader 25, Federal 215 magnum primers helped. Specifically, with a 10-shot group, the 7 or 8 rounds that constitute the bulk of the group would not be quite as tight as with a 210 primer, but the 2 or 3 outliers would not be as far out.

You're not going to get half a minute of angle improvement from optimizing primers. But you'll get some.

I would also recommend trying H4831SC. The .280 AI is not all that different from a .300 Win Mag or .300 Norma Mag scaled down a bit. Danny Brooks, 3-time IBS 1,000 yard National Champion, has often remarked that H4831 aggs better for him in his several .300 Win Mags than the Reloader series. Aggs in 1K benchrest are a little different -- across a year rather than across a weekend -- but for your purposes, that is a plus.

The Vita powders, including N-560, are worth a look, but an expensive proposition for a "maybe." Going the other way, H4350 is a bit fast -- you'll give up velocity -- but occasionally it groups far better.

When I bring up a new long-range chambering, powder and primer choices seem to be larger factors than with a new PPC or .30 BR. Perhaps this is just due to fewer people shooting any particular chambering, but there you are.

Having said all that, I do have to go on record as being against 500 yard shots in hunting, unless someone is one of the very few people with the equipment and skill not to wound game.
 
I use No. 215 Magnum Primers in my 280 Imp and IMR-4831; however I am shooting 140's and not 160's.

I do not like to use any the Reloader powders because of the lack of consistency between Lots.
 
Jackie,

In my eyes, you are a master centerfire benchrest builder, reloader, and shooter. You have chosen to see what the most accuracy you can get from a very good hunting cartridge. This is a worthy project and many of us are hoping you see this thing through and let us know how it all comes out. The best might be .6 inches at 100 yards or more. I, for one will watch for your post on this subject.

Concho Bill
 
For what it's worth I have a ruger m77 in 280 Ackley that I use 60.5 gr of IMR 7828 w/150gr Nosler partition. Avg speed is right at 3000fps and accuracy is .5 for 3 shots on a good day. Interesting thing is the same load of RL 22 is almost exactly identical in speed and group but varies from day to day depending on temps, so I use the 7828 instead. I have killed Elk out to 475 yds with it and most of them with one shot. Draw your own conclusions.

BTW when fireforming for this rifle it shoots like a benchrest rifle 10 shots you can cover with a nickle.. When I go to a hunting load,any hunting load the groups open up some.
 
Rooster 50 said:
For what it's worth I have a ruger m77 in 280 Ackley that I use 60.5 gr of IMR 7828 w/150gr Nosler partition. Avg speed is right at 3000fps and accuracy is .5 for 3 shots on a good day. Interesting thing is the same load of RL 22 is almost exactly identical in speed and group but varies from day to day depending on temps, so I use the 7828 instead. I have killed Elk out to 475 yds with it and most of them with one shot. Draw your own conclusions.

BTW when fireforming for this rifle it shoots like a benchrest rifle 10 shots you can cover with a nickle.. When I go to a hunting load,any hunting load the groups open up some.
Click to expand...

Rooster it is my opinion that if your gun shoots better fireforming than after, it's got a problem. The gun is crooked.

That said, IF what you say is true, the solution is wicked simple. Go hunting with new brass.

al
 
Thanks Al I will remember that. Actually it just opens up a little so I don't worry about it. It has always shot "minute of Elk" and for a hunting rifle I can live with it.
 
One more comment to the original post.

I think the barrel is way to long for the 280 Imp and it would tune eaiser with a 24-26 inch barrel:)=
 
John, I was discussing this with Ed. The thing might be maxed out before it ever gets to the 28 inches.

He is back in town, we are heading to Tomball today, it's cool, but it's going to be a beautiful morning.

He got some 150 grn Ballistic Tips, Short cut 4831, and some VV 165. If we can't get it to shoot today, we will lop the barrel off to 26 inches. Thanks.........jackie
 
Jackie, I believe Jarrett did some crude experiments and found that most of the powder was burnt at about 24 inches.

Happy New Year
 
Jackie,

26" is a good maximun length for a hunting rifle. I my rifle, 4350 seems to shoot best but I use a lighter bullet.

Bill
 
A lot better today!!

Ed showed up with a jug of 4831 short cut, and a box of 150 grn Ballistic Tips. We set my Flags and 35P Chrono up. We are shooting 100 yards.

After a quick work up to just under 3000 fps, I worked with the tuner. (As a note, I added one of my rubber "snubber" features to the tuner, bringing the weight up to about 7 ounces.) I then nailed a 4 shot group, (sort of a compromise), that went about .390. This was very encouraging. We then started going up on the charge, but any thing over 3000 fps was real eratic.

So, we dropped the charge back to a average 2970, and started playing with the tuner. What I found out was you can really make it shoot BAD with the wrong tuner setting. I had some good 4 in 1's, but as the day went on, we figured that initial setting was pretty good.

So, Ed loaded up five, and I shot a five shot group that had four in about .280, and one straight down to open the group to about a .510.

I then nailed a really nice little 5 shot verticle slot that was about .300. The impressive thing was that this load only had a 13 fps spread for the 10 shots. In fact, all afternoon, this 2970 load produced excellent spreads.

It was getting late, so I let Ed take over, (afterall, it is his Rifle). He nailed a 3 shot group that measured .180!!. And his three shots would have been smack in the middle of that last group I shot. Pretty good for a "hunting Rifle".

This was a good day. While we cannot make the heavier 162-168grn bullets group as well, they are certainly within what any normal definition of "hunting accuracy" would be.
Plus, the velocity is pretty darned good with the 150 Ballistic Tip, and the average load at 2970 fps produces outstanding spreads.

All in all, a good day at the range. Although my shoulder is a tad sore........jackie
 
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Good to here you now know the rifle can shoot.

Now comes the quest for the proper hunting bullet; which really only becomes critical with higher velocities and longer ranges.

I would certainly try 160 gr Accubonds. These bullets are very accurate and perform on the level of a Partition or better. I have personally had BT failures, when impact ranges were closer than 200 yards and muzzle velocity was around 3,000 fps.

Hodgdon powders are very stable – good stuff.

The only question I have is why do one inch groups look so BIG? Seems I’m like many of us that aren’t happy until we see nice one hole cloverleaves with our big game rifles:)=
 
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