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Joined: 13 Dec 2006 Posts: 694 Location: MN

I'm coming to the reloaders because I'm guessing this is where the answer will be. How much does barrel length influence the velocity of shot. if all things are equal, is that difference meaningful and how much does it influence down range energy. If this is a stupid question, please excuse.

Joined: 26 Apr 2010 Posts: 3177 Location: NCWa

The velocity gained/lost by barrel length is mainly dependent on what the pressure behind the shot/bullet is at that section of barrel. Slower burning powders have more pressure at the end of the barrel than faster powders, because the slower burning powder has a longer duration of pressure and it comes later in the action. So to answer your question- it depends on what the pressure of your load is when the load is between the two lengths of barrel. It can be anything from virtually no change or it can be dozens of feet per inch.

Joined: 15 Jun 2010 Posts: 1358 Location: Twin Cities, MN

The difference in velocity between barrel lengths in a shotgun are smaller than the average variance within a given load. Don't worry about it.
Jeff

Joined: 16 Jul 2015 Posts: 2124 Location: Hudson,Wy

With much, much slower burning powders in medium and large capacity rifle cases we have come to expect 30-50 fps per inch average. With fast burning propellents used in shotshells, the difference is only a small fraction of this.

Tom Roster once quoted (in person) that nearly 90% of the powder in a shotshell is burned up in the first 4" of barrel. The pressure that generates velocity is diminished very quickly beyond this point. I would not worry about gaining or losing knockdown power with minor or even major changes in barrel length like folks did in the black powder days.

If I remember correctly for every inch of shotgun barrel length the difference in velocity is between 10 and 15 FPS........very insignificant.

Any break open shotgun w/a barrel length between 26" to 30" inch is good to go in my experience. Load velocities and energies should be fine if the load is starting out that way. Shorter break opens are too whippy in my experience. Longer barrels on field break opens tend to be too cumbersome and too long to snake through tangles etc. I like 26" to 28" here myself. My load patterns get there fast enough and hit hard enough if they are built at the bench to be adequate for the job in the first place. Just my opinion based on my experiences.

A repeater w/ a 23" to 24" barrel handles much like a 26" break open. I've found the receiver adds enough length to smooth out the swing. Going w/ a 30" inch barrel on a repeater for upland hunting is overdoing it IMO. Okay for waterfowl over dekes and for sitting still in a dove field where we aren't moving around much or tagging after a hard working dog. Here again, loads adequate for the job will get it done out of repeater barrels anywhere between 23 to 30 inches.

This is just my take on this. Anyone else can buy shotguns as long or as short as they like. It's their money to spend and their gun to tote. Very Happy