I have had three "improved" 280's, two AI and one RCBS. I have also shot a 280 a lot. My 280 with a longer throat, OAL 3.45, is about 30-35 fps behind the "improved" cases at equal pressures. In a hunting rifle, I would use a 22-23" barrel.
Very interesting approach.
I've heard here that long throating like this, fixes the 7mm Rem mag
How long do you trim your 280 cases? ie. do you let them grow longer than 2.540" with appropriate chamber adjustments for neck length?
Originally Posted by RinB
The reason the improved cases are more difficult to get to feed as slickly as a standard is because of the reduced body taper. The shoulder angle has nothing to do with that other than most "improveds" have both.
another good reason to just extend the throat if you have the mag length.
Originally Posted by RinB
Also the idea that a 280 AI is lighter than a 7 mag is just wrong thinking. Same stock, same barrel, same action...the magnum will be slightly lighter because the chamber removes a little more steel.
Kimber 84L changes that
Originally Posted by RinB
I would get the standard built but have the throat extended. Cases and dies are cheaper. Or just get a 270 or a 7RM.
Very interesting thoughts, please elaborate on throat lengthening.
Cheers
No doubt Rick could elaborate and so could l for that matter. But for those so inclined to go look the topic was pretty well covered back in t he 1980's by Layne Simpson in an as rticle entitled "Long Throating the 7mm Express Remington". The data was pretty comprehensive and included diffrrent barrel lengths and powders as good in the 280 as anything today (MRP for example).Some of the data shows velocities so close t o 280AI it m akes us wonder..
I did some work with the 280 over the tears and maybe half dozen rifles. And talked th o RinB to compare notes since he is an old pal goibg back 30 years. After doing all this it's not hard to understand why l could never get excited over a 280AI. It was just easierto get a 7 RemMag if l wanted more than a 280 offered.
Yes the Kimber Montana outs a slightly new slant on the whole thing with an 06 bllt face.
So Bob, seeing how RinB hasn't answered my question and I know you have lots of experience with mag chambered rounds, are you of the same opinion that you can rechamber a skinny short shanked barrel normally seen in say 270's, 280's and 06's in a mag round such as the Mashburn or 300 Win Mag for example ? I've always seen mag chambered barrels to have at least a longer shank area than non-mag rounds. I wonder if my smith would take a Remington Mountain Rifle barrel from a 280 and rechamber it to a 7mm Mashburn, providing I did the bolt face mods first ?
