Barrel length

[CurtDawson]

Does a longer barrel allow lower pressures to reach equivalent velocities? Ex:a 34" barrel versus a 30" barrel
Also what are the pro's acons on "bloop tubes"?

 

[Obtunded]

Depending on the cartridge, there are certainly some gains in velocity with a longer barrel. In terms of pressure, Peak pressures are achieved long before the bullet leaves the barrel but all things,other than barrel length) being equal, the same velocity can be achieved with a somewhat lighter load in a longer barrel. Caveats to that rule abound however.

The costs of a longer barrel should be factored: They add weight to the action and as such must be bedded accordingly or put in a barrel block. There are also harmonic factors to consider. Every barrel has its own harmonic frequency and althoug the bullets may be able to fly faster, they may not be flying more accurately. Ladder testing and finding these nodes may show unexpected results above or below desired velocities.

6PPC Benchrest shooters epitomize that longer barrel length is not the answer to increasing accuracy or velocity. I would argue anecdotally that shorter barrels - in general - are more accurate, but velocity is modestly impacted,10 - 20 fps/inch depending on cartridge).

As for bloop tubes, never use one... no idea.

 

[CurtDawson]

This will be used for the 308/155gr. Plama load