Sunny Slopes: Seating depth does make a difference in terms of accuracy, but it is way behind the effects of the bullet, barrel and bedding. I consider these factors as the 95% or maybe, the 99% contributor's to accuracy. Everything else has an affect, but the magnitude is less.
First and foremost you want ammunition that feeds and extracts. The round should extract when not fired!. I highly recommend that a reloader take their round and chamber it as hard as they can. If the bullet sticks in the throat when extracted, the bullet is seated out too long. It has happened to me, and having to break position, remove the cleaning rod from the scope stand tube, knock the bullet out, get back into position, and resume your string, this will ruin your score in a match. It is probably far worse if you are in the woods! I doubt the bullet could be blow out, and then you have all this powder fouling the action.
Ultimate accuracy is nice and all, but what level of accuracy is needed for the job at hand? And can you hold that hard in the field? There is a trend towards bench rest accuracy in all weapons, which is accuracy for accuracy sakes. It really is becoming a pointless tail chasing religion. I consider an acceptable accuracy standard for hunting to be eight inches circle, which represents the lethal area of an animal. If all shots will arrive within eight inches at distance, then the rifle and load is acceptably accurate. The distance at which the group grows larger than eight inches, than that distance is too far for ethical hunting.
That distance might be 200 yards. Might be less.
Hunting bullet depth has not been that critical for reasonable accuracy in my 30-06's. I think the 30 caliber bullets out there have been developed to be rather jump insensitive. I do have F Class friends who tell me Berger's require a certain amount of jump, but they are trying to keep them all in the ring at 1000 yards. They are also shooting off bipods with sand bag rests, with single shot actions and heavy barrels. I am surprised how many actions don't have ejectors. The round is extracted and the shooter pulls the fired case off the bolt face with a finger. While much can be learned in terms of accuracy from F Class shooters, just because they do it, does not mean much in the hunting arena.
In terms of hunting bullets, I just set these 165 grain Core Lokts to the cannulure, ignored bullet jump, and they shot well.
People who read the inprint stuff, which is advertising catered to their biases, think 600 yards is a gimmie. Well it is not. Having a nice 300 yard zero, I proceded to get a zero at 600 yards, and here is the shot record to get in the 10 ring. I know there were more shots off target before the first one registered.
Once in the ten ring, a good group
Different M70, same era of ammunition. Low shot probably due to a cracked case neck.
When I decided to put a better scope on, I used my garbage bullets in garbage brass. I would have set these IMI FMJBT's to the cannulure, which is probably 3.250" and let loose at 100 yards. I was quite surprised how well they did. Based on what you read from others, you have to seat the things progressively off the throat, to find the sweet spot, and I think that is nice if you are into tail chasing. I think a ten shot group that is 1.65" is fine for junk ammunition.
heavier bullets, such as these military match 174 FMJBT's, I set to 3.30" because that is what I set my 30-06 match ammunition. Seventeen shots in 2.3 inches. I could have gone for 20 shots on target, but it was pointless, and I needed to pack up and move to the 600 yard range.
I did seat these 150 grain pulled, Federal Fusion's out to 3.30", and I forget why. Might have been due to getting the bullet closer to the lands, or, because 3.3" is what I normally use in match ammunition. As it is, shot well
Here is an object lesson on bullets.
This rifle really shot 140 gr SMK's well
and Hornady's well
did not like Core Lokt's
But
this rifle liked 140 grain SMK's
and Core Lokt's did well
something is different, darned if I know what. You just have to shoot the things to figure out their peculiarities.
