I just started loading for my 300 Win Mag. I've got a few questions about the cases. I purchased a shoulder bump gauge and belted magnum case gauge from Whidden gun works. I bumped the shoulders back on my fire formed brass a few thousandths but was wondering about the belt. They range from -.002 to -004 but a few of them were around -005 to -007. Is this some thing to worry about. Im not loading for 1000yds or anything just wanting a better understanding in relation to accuracy. Thanks in advance.
300 Win Mag
- Thread starter idriller
- Start date
Greg Mercurio
New member
The belt is an irrelevant relic, but still works charms for marketing purposes. Headspace on the shoulder and forget about the belt.
I am surprised a reloader hasn’t already recommended a L. Willis height gage/comparator. Normally that recommendation is followed up by purchasing a collate? die.
I have one belted magnum rifle that matches my dies; that is something a reloader can not comprehend, and Winchester, forget talking to Winchester about fixing the problem. I am of the opinion reloadrs are staffing the CS phones
In the big inning the belt was designed to accomplish the same task as the rim; it was designed to hold the case to the rear of the chamber. After the belt replaced the rim anything that happened in from of the belt was of little consequence. No one had to get use to the belt because nothing changed, the rim held the case to the rear of the chamber and anything that happened in front of the rim was of little consequence.
F. Guffey
USMC 77-81
New member
Just for your knowledge, I shoot with a guy who has a .300 WM on a Tikka T3, he regularly shoots 3 shot 1 hole groups at 100 yards, bangs the 600 yard gong and drops Elk yearly.
mikejonestkd
New member
I reload for my brother's Remington 700 in 300 win mag.
using once fired brass we just barely touch the shoulder with the sizing die- essentially headspacing this rifle off the shoulder.
The belt has never been a factor to be considered for this rifle, your mileage might vary.
using once fired brass we just barely touch the shoulder with the sizing die- essentially headspacing this rifle off the shoulder.
The belt has never been a factor to be considered for this rifle, your mileage might vary.
condor bravo
New member
As Greg pointed out, try to adjust your die for headspacing on the shoulder to prevent excessive case stretching upon each firing.
I shot a buck in October with a Mosin Nagant I converted to 300 Win Mag with a Krieger barrel I got for cheap when someone put the wrong threads on the muzzle. I got the stock off Ebay.
Anyway 125 gr Nosler Ballistic Tip, I moly coated the bullet, 66 gr IMR-4166, 3.34" OAL, ~ 3165 fps ~ 47kpsi.
I had it sighted in and shooting well out to 500 yards, but this shot was at a running buck at 250 yards.