My first question would be about overall length I have all the proper tools and overall lengt and overall length tools I see for a 280 is 3.33 for this caliber but I'm getting a measurement which is over a half an inch longer than the standard now I know and I've read that most people like to start 10 thousands of the lands to to find which amountof free bore the gun likes but if all factory is less than 3.33 and. 010 off the lands for me is 3.775 why have i always been able to shoot 1-2 inch groups with about any factory ammo.
Not sure what you are asking! You are looking for the OAL of 280?
Well, Im guessing that you are talking about the 280 Remington, The OAL I have listed is: 3.2 to 3.325 Depending on what bullet you are going to load.
The Over 1/2 inch has me a little
After you load your Complete cartridge (Bullet, powder, primer all in the casing i.e. LIVE ROUND) the complete over all length should be in the OAL size. If not, You did something wrong.
I wouldn't start out trying to get close to the lands yet. Do some more reading.. Then Made some round, get some experience then look into how to get close to the lands.
Welcome and good luck................