Nothing special here just sharing my experience with my first 450bm reloads. Im running the $60 BCA 18" midlength gas 1/24 twist barrel on BCA's website. I plan to run up to 40 grains in halg grain increments when time permits so i will be adding to this. Better groups can be acheived when i get rid of my g.i. trigger.
100yds measured 2.2"
250gr speer deep curl HP
OAL 2.010"
crimped with lee fcd to .473
37.0gr of lil gun.
Avg velocity of 5 shots was 2209fps. Temp was 35 deg.
Next step is increasing by half grain increments until best accuracy is acheived and i might play with OAL. Might also swap lowers to one of my other ones with a better trigger.