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Kens, contrary to popular opinion based on benchrest shooting which has practically zero application to common shooting scenarios, throat angle has little to do with precision nor does having the bullet exactly touching or .015 off the lands. It simply does not matter. Consistent reloading practices, premium bullets, and correct, full pressure powder charges are far more important.
Every common rifle has a minimum and maximum group size it is capable of shooting with modern bullets of the correct diameter (that’s groove diameter +-.002). This is a set reality that cannot be changed and has to do with the quality of the barrel, and the cartridge being used. Take a common bolt action rifle in say 30-06. You take it out with two factory loads and two hand loads. Shoot ten shot groups. You’ll find that the difference between what the rifle “likes” or “doesnt like” is about 1″ worth of difference. Your best ammo may deliver 1.25 and your worst 2.25. You get the feel for that and record it as fact. Now, go and take the load the rifle “liked” and monkey with the COAL from SAAMI standard to touching the lands. You will probably find that your groups are anywhere from 1.0 MOA to 1.5MOA. .5MOA is about all the difference you’ll have between seating depths.
If you get larger swings than .5 MOA, you’ll also find that even with the best load, there are unexplained fliers in every range session, but (coincidence I’m sure) those unexplained fliers will never boost your groups larger than the worst ammunition produced (2.5MOA in this case).
The point is, regardless of throat configuration or seating depth, a rifle is going to function within it’s limits and there’s almost nothing you can do to reliably change that short of rebarreling.
As throats go, the longer, gentler ones are more forgiving than the short abrupt ones which is why europeans have used them since the dawn of the metallic cartridge era.