08-04-2022, 10:15 PM
Dt,
AR-Comp will give the most velocity and with 100% powder burnt out of those three powders at max peak pressure, with a 120 or heavier bullet, in a 20" barrel. H4895 will be close behind it but slightly lesser velocity because it is a single-based powder (Comp is double-based). In third place is the fastest burning powder, XBR which will max out at the slowest velocity.
All will give the velocity you are looking for before reaching peak pressure or full case.
XBR and 4198 are single-based powders so should be more temp stable than Comp, but that's only the theory and might not be the case when you use them.
Your barrel might prefer something other than the theoretical best.
AR-Comp will give the most velocity and with 100% powder burnt out of those three powders at max peak pressure, with a 120 or heavier bullet, in a 20" barrel. H4895 will be close behind it but slightly lesser velocity because it is a single-based powder (Comp is double-based). In third place is the fastest burning powder, XBR which will max out at the slowest velocity.
All will give the velocity you are looking for before reaching peak pressure or full case.
XBR and 4198 are single-based powders so should be more temp stable than Comp, but that's only the theory and might not be the case when you use them.
Your barrel might prefer something other than the theoretical best.