Written by Sierra Bullets Ballistic Technician Paul Box
This is a question that we get on a daily bases on our 800 line. Will my rifle give good accuracy if it has a long throat?
Today long throats are very common in a factory rifle compared to thirty years ago. Most questions we get concerning this is that the shooter will have a new rife throated long enough that they can’t seat a bullet close enough to the rifling and still maintain any bearing surface in the case neck.
First of all, most rifles have two sweet spots on its’ seating depth. One will be up close somewhere like .010″ to .020″ off the rifling. The second sweet spot can be .050″ to as much as .080″ off. Today a lot of shooters only look for the “up close” location and never even consider the far back approach. I’ve got one 22-250 that shoots its’ best .070″ off the rifling.
If you have just bought a new rifle and it has a long throat, don’t be afraid to try the “far back” approach on your seating depth. Many shooters are surprised to find their new rifle will shoot its’ tightest groups with a lot of bullet jump.
There’s also another thing to consider on a long throated rifle as well. Many of these will have a throat that is wide in diameter. It might run .005″ to .008″ wider than bullet diameter. If your rifle has a wide diameter throat, it might very well shoot a flat base bullet with far better accuracy. I’ve seen rifles like this that was giving 1.5″ accuracy at 100 yds. with boat tail bullets start turning in groups in the three quarters of an inch range but just simply switching to a flat base bullet.
So if your new rifle has a long throat, remember to try a flat base bullet and also deeper seating. You might be surprised at the results.