You should use a bit that is just a little bit smaller, but only drill the depth about 2/3 of the distance. This will allow solid penetration into the undrilled wood. 5/16 lags = 3/16 or 1/4 pilot drill bit.
For a 5/16” should be 9/32.
8mm
To convert 516 to percent multiply by 100:516 × 100 = 51,600 %
516/1
516
516
516-434 = 82
It is: 516 = DXVI
516 since 516 is a multiple of 4 (129x4=516)
827 - 516 = 311
5/516 = 0.00969
2 + 516 = 518
516 + 505 = 521