I just measured my maximum COAL using the Hornady LNL tool. After confirming many times over, I discovered that the bullet does not come in contact with the rifling till only the boattail remains in the neck of the cartridge.

I am shooting a 300 Win Mag, custom made, had it for some twenty years. Usually put some sixty rounds thru it every year. My accuracy has always been mediocre...1.5 groups at 100 yds. Have handloaded Nosler 200 gr partitions, the old 180 gr Barnes TSX (original design). Working up new loads for TTSX 150 gr bullets. They are as long (1.307") as the 180 gr lead bullets.

I heard that the Weatherby Mags have very long throats. I'm surprised my has such a long way to go before the bullet touches the lands.

Isn't this unusual? Is this why I have mediocre accuracy? I would have thought that the bullet would be touching the lands of the rifling before exiting the shell casing.

It is usually not good for accuracy to have a long jump to the lands.

On my custom barrels I specify the throat length I want cut for the bullet that I want to use. Mine are all shorter than just any factory barrel.

Is it worth getting a gunsmith to fix this or is it better to just get a new barrel?

I don't think what you have is unusual. I have a couple rifles that won't allow me to seat lighter bullets to touch the lands, particularly if I am using a boattail bullet.

If you don't get good accuracy with the bullet seating it away from the lands, you can switch to a flat base bullet or go back up to a heavier bullet.

There could be a dozen reasons why you aren't getting better groups, but with my own personal standards on a big game rifle, 1.5" groups are perfectly fine. But if you are intent on getting better than that, you might want to bed the rifle before you replace the barrel.

Weatherby is known to have a long throat or "free throat" in an effort to reduce/eliminate "spike" pressures in their rifles or sort of a safety valve if you will. To alter this would require having the barrel "set back" and shorten the throat distance, but to have that bullet against the lands and grooves w/ the pressure you are dealing with may well not be a good idea. I don't know whether it would work OK or not, but experienced 'smith/users could better advise on that issue. If you can set the barrel back and reduce the "jump" beleive that would be easier and less cost than a new barrel and accomplish the same goal??? If you do set it back, don't be shocked that whatever is written/stamped on the barrel itself will not be in it's original position. There is a method to keep the same position, but you would need to specify that with the person doing the work. It can be calculated in other words. Good luck.

Scroll down to "From The Lab". In their testing Barnes found that rifles usually have more than one OAL sweet spot. One up close and one farther back.
http://www.barnesbullets.com/resources/newsletters/bull...007-barnes-bullet-n/

Barnes recommends that you seat their bullets .050 off the lands for starters.

The long throat is not necessarily the reason for the mediocre accuracy. Before you do anything to the barrel there are a lot of different loads you can try. My Wby has a long throat and the accuracy is superb. Rebeding may also help. What about your scope, rings, and mounts? There are so many things that effect what size groups we get other than the barrel (although it can be the culprit).

I can't seat my loads close to the lands in my Rem 700 in 300 saum unless I use it as a single shot. If I seat close to the lands the cartridges will not fit the magazine. Haven't started reloading for my Savage 114 classic in 300wm so I don't know how close to the lands I can get it.

quote:

Originally posted by BC Sportsman:


I am shooting a 300 Win Mag, custom made, had it for some twenty years. Usually put some sixty rounds thru it every year. My accuracy has always been mediocre...1.5 groups at 100 yds. Have handloaded Nosler 200 gr partitions, the old 180 gr Barnes TSX (original design). Working up new loads for TTSX 150 gr bullets. They are as long (1.307") as the 180 gr lead bullets.

Is this why I have mediocre accuracy? I would have thought that the bullet would be touching the lands of the rifling before exiting the shell casing.

Hey BC

You shoot Partitions which are great field perfomers but are not accurate

Sounds like you shoot the Barnes X bullets which were typically terrible in the accuracy department with very few exceptions

Now you are shooting 150 gr bullets which are really not heavy enough for the 300 win mag and the twist you probably have which will not be optimal for accuracy

It sounds like you are handicapping yourself with bad bullet choices. Try the 180 gr TTSX with 75.5 gr RL 22 or the 200 gr Accubond with 72.5 gr RL 22 and you will not only be able to seat closer to the lands and have more bullet in the neck but also will be shooting what the 300 win mag is intended for.

JMHO