Load performance and barrel length

[Showman]

For awhile now, I have been trying to find out how much difference that barrel length affects shotshell performance. One authority says that shotshells reach their power peak in the first 18 inches of barrel and that any barrel much longer than that is simply useful for swinging the gun. Another says that a barrel needs to be 24 inches long to get the best pattern and power out of a given shotshell. Another says that the old "saw" about longer barrelled guns shooting "harder" is still true...at least, up to the first 28 inches.
Does barrel length really matter that much in tightening patterns and hitting harder?

 

[rcmodel]

No.
The truth is somewhere around 20" - 24".

And the degree & uniformity of the choke you are using is much more important to getting a tight pattern then barrel length or velocity.

The faster you start out round balls of shot?
The faster it slows down real fast.
In this case drag is king, and round balls have a lot of drag.

Todays hardest shooting, longest range shotguns are probably sold as Turkey hunting shotguns.

And an awful lot of them have 22" barrels.

rc

 

[jmr40]

Velocity gains after 18-20" are small, but real. A 28"-30" barrel will shoot faster than an 18"-20" barrel, but minimally so. The differece between 24" and 26" is so small it might not even be possible to measure. If I needed an 18"-20" barrel for use in confined spaces it sure wouldn't be worth the small gain in velcoity for a more cumbersome 28" barrel.

As RC noted most turkey guns have 20-24" barrels and don't have any problem getting enough speed to kill turkey. Just personal preference, but I don't like much shorter than 20" even on a gun meant for home defense, nor longer than 26" for hunting. After about 20" it really is more about balance and how it swings.

Barrel length has nothing at all to do with patterns. With todays interchangeable tubes an 18" barrrel with the same tube will shoot the same pattern as a 32" barrel with the same tube and shotshells.

 

[hardluk1]

The longer barrels do aid aiming and do give smaller increase in velocity but reguardless you still have to find the shoot and choke combo that pleases you best. Thanging from brand to brand of ammo , even length of ammo as in 2 3/4,3 and 3 1/2" shells .

I a younger life all us guys hunted in south floridas swamps and found when patterning our shotguns for buck shot even to like shotguns may like different brand, size and length shot. Post screw in choke days!! Still the same today but screw-in chokes are much better at controlling patterns.

 

[oneounceload]

There re numerous studies done, most available on the web, that show a very small difference between velocities at 30"and 18 - somewhere around 25 fps - which can be the normal deviation in a box from the factory - so no, there is not enough to worry about.

"Hitting harder" from the older days of BP shotshells, and even the early paper ones had some merit for longer barrels, but in general - with today's modern ammo, 18 will get you everything a longer barrel will EXCEPT for a longer sighting plane when used like a rifle or smooth swing dynamics when used for birds on the wing

 

[Fred Fuller]

Does barrel length really matter that much in tightening patterns and hitting harder?

Basically, the answer to that question is "no."

Any barrel length sufficient to fully burn a charge of modern smokeless powder (14" - 20" or so) is going to get most if not all of the potential velocity out of that powder charge.

And the internal geometry of the barrel (forcing cone, bore, choke) and the construction of the shotshell (wad construction, pellet size, roundness, hardness, pellet protection) has more to do with patterning than the length of the barrel.

Thee are LOTS of variables - but barrel length is one of the if not the least important.

 

[Virginian]

A normal shotgun charge will continue to gain velocity up to at least 34". How much depends on the weight of the load and the powder used. The powder may be burned by 20" or so, but that gas behind the charge is still pushing.

 

[Showman]

Thanks for all the replies, everyone.
Virginian, I have a question for you: you mentioned that gas continues to push a given load even after the powder has burned out in the first 20 inches of barrel. How much of a difference would you say that this added push is making?
The reason I ask all this: I like to hunt turkeys, but lugging around a 28 inch barrel has become more and more of a hassle as I get older. I have an extra barrel that is 21 inches and it sure makes for a more pleasant turkey gun to carry...am I really losing that much load performance, going to a shorter barrel? Everyone else on here seems to feel that it's not enough to worry about. I sure like how easy that short barrel carries in the woods, especially when everything greens up around here.
I'd also like to go shorter on a barrel, say, for early season squirrel hunting. I just want whatever load I use to hit game hard enough to ensure a clean, humane kill with no wounding or suffering.

 

[tactikel]

My Mossberg 835 Turkey gun with 24" barrel will actually out pattern my Browning Superposed Trap gun with 30" barrels.

 

[oneounceload]

Barrel length has NOTHING to do with patterning - the choke and ammo combination do

 

[303tom]

A normal shotgun charge will continue to gain velocity up to at least 34". How much depends on the weight of the load and the powder used. The powder may be burned by 20" or so, but that gas behind the charge is still pushing.

I concur, load & powder burn rates make all the difference. Factory ammo, 28 to 30 inches is about a norm..............

 

[ZVP]

Handling

Since I built my H/D gun I have discovered a huge and new respect for short barreled shotguns! Just throwing the gun around during normal shooting and pratice, I have found the 20" ro feel near ideal! I am sure that an additional 4" wouldn't queer handling and might improve follow-through.
I am working with a 40" OAL and it comes to mount naturally, way more so than when the gun had it's origonal 30" tube.
In cutting the barrel I lost my choke and aam shooting Cylinder bore. This gives 17" patterns at 25 yards and I wonder what sort of running jackrabbit gun this would make? Maybe the pattern wull open too much to be effective with a #4 Phesant load (my usual hunting load).
When I cut the barrel on the pump I was looking for BuckShot patterns of a "Human Wide" @ 15 yards and it now shoots a Mil S'pec 9 ball load in a 9" pattern @ 15 yards! Perfect for my H/D uses! Indoors and at close range itputgs all it's pellets in the torso. I had not intended for a long range pattern with Birdshot, just Buck Shot and Slugs, which I have accomplished.
I will have to devise a way to test @30 yards with all loads to see where it'll shoot? Like I said I was after close range preformance and I got it1
Out of curiousity, is there a standard pattern open-up to look for at say 20 and 30 yards?
Thanks,
BPDave

 

[oneounceload]