Yes, C.O.L. = overall length.
From Hodgdon's web site reloading data page,
http://data.hodgdon.com/cartridge_load.asp
115 GR. LRN IMR PB .356" 1.100" 3.3 974
26,900 PSI 3.7 1061 32,500 PSI
115 GR. SPR GDHP IMR PB .355" 1.125" 3.6 957 28,300 PSI 4.0 1038 32,000 PSI
While the FMJ bullets, that you have, aren't that much different than either of the two types that Hodgdon recommends for that powder, it's enough to cause concern.
From the data above, it's obvious that similar, but different, bullets require very different loads, for the same results.
The bullet shape, design and material all make a difference in the loading data.
Generally, jacketed bullets have more friction down the barrel than lead, requiring more powder for the same velocity.
But the additional friction also adds pressure.
Without a way to test each and every type of bullet, substitution can be hap hazard and possibly dangerous.
If those FMJs and the PB powder were the very last components on the planet, maybe it would be worth experimenting.
It would be be better to just get the recommended powder for the bullets you want to use.