Range Report 280 Remington ballistics versus 6.5 x 284

[gene so]

Hello, After recently completing a rifle range to 800 yards complete with a concrete benchrest I am facing the fact that my 6.5 x 284's bullets are really getting blown around here at 6,500 feet at the foothills of the Rockies.

Are there members of this forum who have practical experience with a .280 Remington or a .280 AI utilizing the 180 grain VLD 7mm bullets? I am considering adding a barrel to one of my target rifles in this chambering, if I can find that the heavier bullet is much better at the long distances especially with major winds.

Thank you for any input from an experienced rifleman in regard to this subject.

Gene So

 

[Greg Langelius *]

Re: 280 Remington ballistics versus 6.5 x 284

Multiply muzzle velocities by their BC's and compare. The higher number has the ballistic advantage downrange.

My experience with loads and pressure signs indicates that published max 280 loads may be conservative. I stay within published max because I like the accuracy and flat trajectories I'm getting with those loads, I figure that by staying conservative, I'm using the additional case capacity in a manner that respects bore longevity.

I use H-4350; that and H-4831 are excellent propellents for the heavier bullets in the .280 chambering.

Make sure your 280's barrel has enough twist for the 180VLD's. The 1:9" twist is expected to stabilize 168's and maybe 175's. Yes, the 180 has great numbers; but lighter bullets can still do a good job out of the 280. The additional case capacity of the 280 allows the 150 to beat anything you're able to shoot out of the 6.5-284 without even breaking a sweat, pressures-wise.

The highest bullet weight I've tested yet is the Nosler 150gr BT. I have not yet been able to test the 280 beyond 250yd (at approx 1000ft ASL). My Pejsa Spreadsheet indicates that the 150 NosBT at 6500ft altitude has a corrected BC of about .650. As such, I expect that the 150 has enough MV and BC at that altitude to be quite adeaqute at 1000yd. Even at my 1000ft altitude, it still computes as supersonic at 1000yd, at yours its up over 1400fps.

The 1:8" twist 7mm L-W barrels I've looked into carry a premium pricetag over the 1:9" and 1:10" barrels, so limiting bullet length/weight from the start can have advantages.

Greg

 

[Warboar_21]

Re: 280 Remington ballistics versus 6.5 x 284

I have a 280AI with a 1:8" twist. I have shot the SMK 168grs out to 600yds and have had very good results. I use RE-22 as it proved to be the most accurate from my rifle. I haven't shot the 180s yet as I have had great results with the 168s. I would like to give the Berger's a go and see how they perform.

 

[GreatGonzo]

Re: 280 Remington ballistics versus 6.5 x 284

I shot a 280AI for a couple of years in tactical matches. It is a great cartridge. With a 25" barrel, I can get the 180 Hybrid VLD to 2900 with H-1000. With a longer barrel you could certainly get it up closer to 3000.

However, lets assume that you are shooting a 280 AI with a 180 Hybrid at 2900.
Let's assume that you are shooting a 6.5x284 with a 140 Hybrid at 3100.

The ballistics are very similar. So similar, in fact that the windage at 1000 yards is the same. They both go trans-sonic at about 1800 yards, your windage at 1800 yards is the same for both. The 6.5x284 takes less elevation adjustment, but that is a consistent number so it is less important and they are both laser beams. They will recoil nearly identically and produce nearly the same amount of energy on target. Hell, they are the same cartridge....

Except they are not. The 280 AI will last for thousands of rounds. Mine has 2000 through it and shoots better than it ever has. I have not been nice to it. I shoot too fast in too hot weather. I really have abused it. Find me one person that is pushing a 6.5x284 hard that has seen more than 1200 rounds. It doesn't happen.

At your elevation, I would trend towards a 1-8" twist to make sure you can stabilize the 180 at your elevation, especially in cold weather.

on a side note, If your bullets are "really getting blown around here at 6,500 feet at the foothills of the Rockies" with a 6.5x284, you are going to be sorely disappointed with any other cartridge. It really doesn't get any better than that with anything else.

 

[bohem]

Re: 280 Remington ballistics versus 6.5 x 284

Greg- well written per usual.

One additional note: My 280 Rem shot the 180 Hybrid Bergers, 180 VLD's from Berger, JLK, and some 189 Cauts. without any trouble from a 9tw.

Gonzo - the higher the relative DA, the more stable they get. If they're stable at sea level, they're stable at 6500'

 

[grizzlybar]

Re: 280 Remington ballistics versus 6.5 x 284

I have been trying to find what to re-barrel my Mauser .270 win. in what is the COAL on the .280 & .280 AI pushing the heavier bullets ?

 

[turbo54]

Re: 280 Remington ballistics versus 6.5 x 284

Surprised no one has suggested this guy switch to 284, or 284 Shehane, considering he's already got 6.5-284 brass and tooling.

 

[Heman]

Re: 280 Remington ballistics versus 6.5 x 284

I shoot a straight .280 Remington for NRA Long Range. Using 175gr SMKS's moly coated and 61.5gr of H1000 my velocity is somewhere around 2890ish, and I come up 24.5 MOA from 100yd for 1000yds. If I shoot the 180 Hybrids I'm coming up 23.5gr. If you run the numbers either bullet shoots inside the 6.5x284 when they are ran at the standard 2950ish that most LR shooters run them at. Yeah there is more recoil but it isn't much. I pulled my first barrel off after 2100 rounds. That was with about 1200 using H4831SC. Running H1000 and moly I'm hoping to get around 2500 on the second barrel.

 

[grizzlybar]

Re: 280 Remington ballistics versus 6.5 x 284

Heman what coal do you run for best ballistics?
I'm interested in the .280! I want to re-barrel a Parker-hale chambered in .270 win. the Action is a Mauser I think it's an FN, has a radial safety behind the turned down bolt, the action is flat on the bottom , large ring 3.40 magazine , with the release forward in the trigger guard holds five rounds!
I hope I can run a .280 in that action!

 

[TXHillCountry]

Yes you can

Heman what coal do you run for best ballistics?
I'm interested in the .280! I want to re-barrel a Parker-hale chambered in .270 win. the Action is a Mauser I think it's an FN, has a radial safety behind the turned down bolt, the action is flat on the bottom , large ring 3.40 magazine , with the release forward in the trigger guard holds five rounds!
I hope I can run a .280 in that action!

Grizzlybar. The 280 Remington (case length 2.525 OL 3.330) and 270 Winchester (case length 2.540, OL 3.340) are basically the same, with the exception that the .280 shoulder is moved forward about 0.10 inch. Yes you can use the .280 in that action. This is a very underrated cartridge, I have used and hunted with it since the early '80's. I have two Ruger 77's one sighted in for 150 gr (150gr Nosler ballistic tip. 51.5gr IMR4350) the other sighted in for 175 gr (175gr Nosler partition, 56.5gr H1000). Both are deadly. I use the 150's on white tail, the 175's on mulies and elk, both have provided one shot kills on all targets out to 400+ yards. This round is accurate!!!