I constantly see different opinions given for how much distance a bullet should be set “off the lands”. Some describe seating into the lands, others .005”-.010” off the lands, some manufacturers suggest .030”-.050” off and I’ve read that Weatherby factory rifles and ammo may be as much as .250” off the lands. Why does there seem to be so much inconsistency, and how does it effect accuracy?
accuracy, pressures, ect. Wby uses lots of free bore, this "bullet jump" reduces chamber pressures. Some feel if the bullet is seated just into the lands, it gives the bullet a straight start. Most guys will test their rifles with many differnt bullet seatings to find the best accuracy setting. The old norm was .010 off the lands, i personally like just barely touching, or just off. It also depends on the bullet your using, monolithic solids like .030 to .050 off the lands. There are many opinons out here,im sure you will hear more.
There's no real answer to the question of which one is the best. I generally start .010" off and vary a little to see if I can get the groups small enough w/out jamming it in. If I can't get the results I want, I jam the .020" and work up and down from there. Your gun will tell you where it likes it [img]/ubbthreads/images/graemlins/wink.gif[/img].
It would be wonderful if there was a standard for reporting load data. So many posts have incomplete info like powder and velocity but no charge weight, or powder and charge but no velocity data. Tools like Stoney Points comparator are not that expensive and provide ogive measurements for "off the lands data" as opposed to OAL that cannot be misunderstood by anyone looking for safe and accurate loads. I'm not complaining because I have learned so much by these posts but it is frustrating and worrisome from a safety point when load data is put together from several posts providing incomplete data. RP
To post charge weights is not allways best, you dont know what your getting by someone elses posts. If i post 131grns Re-25 3000fps for a 408 C-T rifle, sounds real nice and maybe in his rifle its ok or maybe not. You read this post and say "wow i'm going to try that in my rifle" you load some test rounds up, go to the range, Booom! your bolt wont move? you just loaded up a cartridge that in all possiblity was 6grns over max. Who's fault is that? I have seen this happen many a time over, what "may" work in one rifle, wont work in "many" others. No matter what loads are posted here, i still start much lower and work up. Another example, Kirby has his 338AM i have the 338Snipe-Tac, basicly the same round. His gun is a monster bench rifle, 40" bbl, 2" action. My gun is a 16# hunting rifle, 33" bbl, 1.600 dia action. There is no way i can use his loading data in my rifle. When he builds his light hunting version, i suspect then they will be close. There are too many variables in reporting load data. If i post load data i post it low on purpose and say work up to your top loads, or this load may not work in all rifles, this is the most responsible way to do it. Not saying that most people here dont allready know that, but some nubie comes along reads a post on a 300rum shooting 3500fpsm 200grn bullet and loads his up, blows the case or maybe worse, and it does happen. So i guess its up to the poster weather or not he wants to give out such info.
~Just my opinon~
I have a 22BR that I load bullets touching the lands and a 338/300RUM that there is many thousands from the lands and both shoot really well.There are too many variables in shooting it is just the nature of the beast!Get you a pencil and paper and sit down and try listing all the factors involved with a bullet leaving the muzzle and striking the same point at any distance, I am amazed at what accuracy that can be attained.Your question was already answered by the above posts just wanted to add my thoughts.