26" barrels

[scalerman]

I had asked this question in the gunsmithing forum and as yet have not had any replies. Maybe you guys can help me. Does anyone have any information on the 280 Remington as compared to the 7MM Remington Magnum when both are shot out of a 26" barrel?

[Rocky Raab]

I don't own either one, but as luck would have it there's an identical question over on another board that I visit.

The consensus there is that there is only about 100 to 150 fps difference between them when using equivalent loads with the same bullet. Except that the Magnum has much more recoil and blast, of course.

[scalerman]

That's kind of what I thought. I have thought for a long time that in most of the magnums it is the longer barrel that give most of the increase in velocity not the increased powder load. There really isn't much difference in velocity between the 7MM and the 280 anyway so I just wanted to confirm my suspicions. If any body has any chronograph data that would be really sweet.

[bsterns]

In Speer's reloading manual they list a starting load of 49 gr. of IMR4895 for the 7mm mag with a muzzle velocity of 2970 fps. The max load for 280 Remington using IMR 4895 is 48gr. giving a mv of 3073 fps. These loads are for a speer 120gr. bullet #1620. So the 280 is 100fps+ faster than the 7mm mag using 1 grain less powder and using the same bullet. I was surprised at this. Obviously the 7mm mag case with an equivalent in weight load to the 280 Rem does not build the pressure necessary to get the same velocity as the 280 Rem. Of course the potential for faster loads with more powder and recoil lie with the 7mm Mag with it's bigger case. I own both calibers. I prefer the 280 Rem because it has less recoil and does the job on anything I might shoot at with 7mm caliber. For larger game I like my 338-06 using 180 to 250 gr. bullets with less recoil than 338 Win Mag. with about the same reduction in velocity as the 280 vs 7mm mag. Same reasoning.

[moneychanger]

i have 7mag encore barrel & i'm tempted to sell it to GET a 358 winchester barrel , or maybe a 35 whelen barrel, although a 280
26" barrelo for my handi rifle sounds interesting.

[Riposte1]

I am a 7mm neophyte so any opinion here would be a bit presumptuous. I just bought my first 7mm caliber last week...a Winchester Featherweight in .280 Rem.

I did however build a couple of 7 mags for people when I was first starting in the custom gunsmith business (a "semi-past" life as I am really too busy to do that these days except as an interesting sideline). Those rifles sort of steered me away from the 7 mag (I only used factory loads for testing those guns) - too much fuss and bother for a glorified 30-06.

I do however have a .264 Win Mag and a 6.5-06. To be sure, the mag will push bullets faster but I think a similar condition exists; the Mag will not do anything practical that the '06 case will not do unless it comes to a slow way to just burn up excess powder (I would rather just light the whole can at once to dispose of it )

OTOH, if you have a 7mm mag which shoots good, does what you want and you dont mind the noise...more power to you! There is not a lot of practical difference between any of these things until you get to the exteme caliber ends or vast differences in cases. If you think so get one of Bob Hagels excellent works on practical laods and see how they stack up next to each other.

Riposte

[Rapier]

I reload for the 280 AI and own two 7mm Mag guns. They produce identical results. The 280 should fall about 100 to 150 fps under the 7mm mag, based on the standard AI differental.
Ed

[scalerman]

You said the 280 should fall about 100 to 150 fps short. Is that your observation on all bullet weights or is it just on the lighter 7MM bullets?

[Ol` Joe]

No one can really say what the difference is other then to estimate. The different components of the load will change the results, so will the variations in chambers and barrels. One might have a min sized chamber and bore in his rifle and find it shoots faster then the books claim it should and the next guy with a sloppier bore may be 100 fps slower then he should be. The only way to be sure is to cronograph the load and rifle.

The "book" std for the 280 with 140 gr bullets is 3000 fps the 7mm mag runs the same bullet 3150, 150 fps difference. The 280 with 160 gr bullets goes about 2890 tops vs about 2950 fps for the magnum, less then 100 fps. Raipers estimate looks about as close as you`ll get with all bulet wgts.