Originally Posted by grit
As stated, the 300 is actually smaller than the 7mm. There are two good reasons to utilize the 300 cartridge. First, Norma makes excellent brass for the 300. With the 7, you're stuck with mediocre brass and thorough brass prep. In my experience, this is a big factor. Second, the longer neck supports long bullets better and minimizes throat erosion.
The 300 gives up nothing in performance. You get top quality brass and longer throat life. While the 7WSM is excellent, I prefer the 7-300.
Good brass is allways a plus if you can get or afford it. I have never had a problem with the
available brass even though I have had to discard a few in the initial case prep.
I use to be a believer in the "At least one caliber of neck length philosophy" until a very learned
gunsmith informed me that it was the amount of contact surface of the neck to bullet(Square
inches) that made the most difference. the 300 Win Mag is a good example, inside Neck Diameter
is .308 and inside neck length is .264 (.044 thousandths shorter) and the 300 WM is known for its
Lots of cases have necks shorter than the bullet diameter and accuracy is hot an issue. I still like
the necks longer but do not fret over the ones that are not. So this would not be a reason for me
to abandon or change to one that is not one caliber long.
Why do we Improve cartriges ? Normally to get more case capacity to increase velocity.
True there is little difference in the two but the advantage has to go to the 7 WSM in my opinion.
Grit: I like and respect your post and opinions so in an effort to learn more I have a question.
How can throat erosion be reduced by a longer neck ? The overall case length is the same and
the bullet exits the brass at the same point and exposes the throat and chamber to gas and
unburnt powder at the same time and place.
This is not a smart ass question and I am always open to learn more.
So the fact that the original poster ask the question "is there a substantial gain with a 7/300 WSM
over the 7 WSM my opinion is NO, in fact like with any Wildcat there are other issues that you
have to deal with.(Custom dies,brass with the wrong head stamp, lack of factory ammo ETC.
The only reason I build wildcats for myself is to fill a niche that no factory round can or does.
Again this is not to start anything just a question, and my opinion.
J E CUSTOM