This is a continued disussion from the 240 SMK thread under Beyond 1000 yards out of respect for the moderators we moved it here.
This is the set up I use for achieving the most precise bullet seating alignment possible for the most accurate bullet flight possible for long range precision shooting.
It starts with an inline bullet seater. It can be custom made or a Wilson is very popular. (type in Wilson Inline Chamber type bullet seater in your prefered search engine). It is a body die with a bullet seating stem above that when used with a arbor press pushes the bullet into the case perfectly straight. We custom make these for our customers when we build rifles for them. It must be machined by a competent smith or machinist for maximum tolerance..or in simple terms STRAIGHT. The center of the stem MUST be perfectly aligned in the center of the seating die. The bullet aligns perfectly in the same space the bullet seating stems rests.
Now, if your brass has perfect or no run out the bullet will be pressed perfectly straight down into your case. The center of the bullet is now center perfectly with the center of the flash hole.
If you could draw an imaginary line from the top of the bullet straight down through the case it would exit out the primer pocket/flash hole and would again be perfectly centered with no run out.
If your chamber is straight in your rifle and your action/bolt face is true and your dies are CUSTOM made by a machinist and your using this bullet seating method you will for sure launch your bullets much straighter out of your tube which means at long range much tighter groups and better scores. It is a series of events that much be followed to achieve this. And it starts with your rifle. You can load the most accurate ammo possible but if your rifle isnt true as in bolt face, raceway and barrel bore to boltface firing pinhole none of it matters. Yes, good ammo is always going to shoot better but when we are talking baout splitting hairs it ALL must perfect. Then the shooter has the pull the trigger with no human error and correct dope elevation/windage to get the bullet to it's intended target precisely. It never ceases to amaze me how many times I hear a tactical/sniper shooter who says "I dont care about groups or shooting groups at long range it where I hit the target" as in score. Well, if your bullets not coming out straight and your weapon system isn't up to par then your not going to have as high of a first shot hit percentage rate as the shooter who does. Yes a lot of off the shelf rifles or non custom rifles shoot great. I tune dozens and dozens of them and train the men who own them. But they will never out shoot a custom gun that is custom made loaded with these technics. The difference between a 3/4 MOA rifle and a 1/4 MOA rifle is day and nite. The reality is a most rifles are about 1 MOA or slightly better 50% of the time. There are sub 1/2 MOA rifles and thats where it at for a long range tactical PRECISION rifle. It is more forgiving if the shooter is off on his windage and elevation. Please dont get me wrong. Yes I know that there are shooters out there who have factory rifles that can just plain shoot or out shoot a guy with a custom rifle with what they have. But what I'm saying is if they had a custom rifle built true and hand loaded their ammo to the specs we suggest they would always shoot much more precise. And we all like to use the word precision so we owe it to ourselves to give that word respect as for the men who achieve it. There is always room for improvement in most shooters set ups to the point of diminishing returns. But when a shooters gets there he knows it.