Home Forums Hunting & Shooting Ask The Gunwriters 7mm Rem Mag Vs the 270 Wby

I just read Allen's post on the cartridge, and agree with what he said, since I have encountered the exact same thing.He is correct. I have two 7 rem mags in the safe right now that vary a good deal in the charges they take to deliver a certain level of velocity with 140 and 160 gr bullets.Throat lengths, barrel dimensions, bullet,etc all have a tremendous bearing on delivered velocities, and I have experienced this with the cartridge many times.

BUT, in just about every rifle, I have always been able to duplicate what I regard as pretty standard velocities in the 7RM which is to say 3200-3300 with a 140, and 3100 or so with a 160 WITHOUT undue pressure signs, reasonable case life, sterling accuracy and great field performance.To take it a step further....

Because I have built and used any number of 7 mags, 270's, various 300's, etc. deliberately varying not only throat length, but internal barrel dimensions as well, I feel very comfortable stating that the 7 RM IS NOT UNIQUE IN THIS REGARD.It is just that the cartridge is WAY more popular than many other cartridges, is made by different manufacturers,given different throats, barrel styles and dimensions, etc. to such a degree that uniformity across the board is hard to come by, and I think this is why data for it is "dumbed-down". You have to work up loads suited to YOUR rifle; if you do, it will perform just like a 270 Weatherby.The powder charges may vary from rifle to rifle to reach the same velocities, but I have always been able to get there.

I have seen the same thing with...the 270 Winchester,300 win mag, 300 weatherby,and 280 Remington, to name a few.The 300 win mag is one of the easiest cartridges to load; but I have seen throat length and barrel dimensions or type make a difference one rifle to another in that cartridge, as well.Ditto the 270.

Any body taking a hard look at the two cartridges will see that the 7RM and 7 Weatherby have about identical capacities; yet the 7 weatherby uses heavier charges, gets higher velocities. Ever wonder how come? Mostly, it's the throat length. Long throat a 7 RM, you'll get 7 Weatherby velocity, and likely your loads will resemble 7 Weatherby data.

Read Dober's comments as well; he is right, too.