View Full Version : Shotgun bbl length=reach? better pattern?

September 10, 2007, 05:45 PM
Hello everybody,

I'm totally new to shotgunning and am thinking about outfitting my 18.5" mossberg bbl with a 20" with screw on chokes..

I want a pretty much do-all shotgun, from HD to backpacking to harvesting small game, big game, clays, etc.. So while the bbl may not be the ace of any task, I am hoping for a jack of all trades..

After much searching, I am still emptyhanded
So I must ask:
1. Does anybody know if the 20" will provide me with the reach of a longer barrel?
2. Can they still produce tights patterns at range when compared to say, a 24 or 28"?
3. What are vent ribs for?
EDIT: 4. Will the IC choke work as well as CYL for slugs?


Bill DeShivs
September 10, 2007, 06:25 PM
A 28" barrel will get you 8" closer to your target than a 20"!
As long as the choke is the same, there is no advantage in a longer barrel.
Some people feel that a longer barrel "swings" better than a short one, but that's because they are used to long barrels. You could have screw-in chokes installed on your 18" bbl, for that matter.
Vent ribs provide a level sighting plane, rather than the sloped/curved plane of a plain barrel.

September 10, 2007, 06:40 PM
There is a lot of fact vs. fiction in shotgunning.

A 20" barrel with screw-in chokes and rifle sights should work very well for HD, turkeys, deer and small game. It won't be ideal for clays, doves, waterfowl or pass shooting anything, but it will work. The fact is that longer barrels have a longer sight radius. They tend to produce a smoother swing because there is more mass in front, and therefore, more inertia. It is slower to get moving though, which is why you don't see too many quail guns with 32" barrels.

Velocity will be affected a little but not much. "Reach" is more a function of pattern density and being able to put the target in the center of the pattern. IC is usually recommended by the gun makers for foster-type slugs, but the only way to know for sure is to try them both and see which one shoots to point-of-aim, gives a tighter pattern or, preferably, both.

Theory: pattern density is more a function of choke than barrel length.
My experience: my 11-87 patterns better with a 26" barrel than it does with a 21" and that is using the exact same choke and load. (I know it's not supposed to make that much difference, but it does in my gun.)

If you can keep the 18" for HD and use a 26" bbl with screw-in chokes for everything else, you'll have the perfect combination, IMHO.

September 10, 2007, 07:11 PM
Thats exactly what I did.
My gun came with a 28" ported ventrib barrel with a few chokes, then I got a 18.5" barrel for $80
I feel this setup covers all my shotgun needs

Brad Clodfelter
September 10, 2007, 07:43 PM
You ask a very good question and I'll try to answer to the best of my knowledge of testing shotgun barrels of various lengths for patterning results from various loads at different distances. If you want the best do all barrel for say all around hunting from doves, quail, squirrels, and rabbits, the 26" to 28" barrel length will probably be what I would pick to be idea for all around use. Now I prefer the 28" over the 26" for shooting doves because of the longer focal plane that the longer barrel provides when shooting doves when it comes to getting on them and leading them. A longer barrel just makes it easier to do. I have a 30" barrel on my 1100, and it works great for doves. Now if you rule the doves out, the 26" will be the idea length. The 28" barrel and the 21" barrel that I have tested on paper at 25yds was a total shot difference of about 12-15 shot, with the edge going to the 28" barrel. I would say that Bill above probably hit the nail on the head about being that much closer to the target to give you the slight edge in the small difference of pattern advantage. But, too, I would say it very well could be in some cases that some shorter barrels will out shoot the longer barrels. But I would put my money on what I have found to be the case in my testing of different barrel lengths that in most instances the longer barrel will have a slight advantage in pattern density. As for shot speed vs barrel length, I have read that in chronograph tests done to check shot speeds from different barrel lengths that a 18" barrel will provide optimum shot speed. Now I would say it safe to say that some heavy magnum or turkey loads may need longer than 18" of barrel length to get all the powder burned in these loads with heavier powder charges. But I'm assuming that so don't quote me on that. But a barrel longer than 18" will actually in the test I read, slow the velocity of the shot charge down to some extent. But I would rather have a longer barrel with the right choke that will give me optimum pattern density vs shot speed anyday. I hope that makes sense to you. I prefer a 28" barrel length if I had to pick one. But a 26" will work very well and save you a little weight.


Brad Clodfelter
September 10, 2007, 08:09 PM
Didn't get all your questions answered, but I will get some I missed. The 21" 870 turkey barrel dropped a jake at 47yds in his tracks. So, yes you still can reach out quite a ways with a shorter barrel. I would get a vent rib. I doubt if you can buy a newer shotgun or barrel for a gun now that doesn't have a vent rib unless it's a sighted slug barrel, or a single barrel shotgun. They are that popular. It gives you a raised, sighting point to aim from making it easier to get on game to shoot rather than having to dig your cheek into the comb of stock when shooting from a non-ventrib barrel. It just in my honest opinion gives you a more natural head, neck position to shoot from.


September 11, 2007, 02:51 AM
100% answered my questions!

Brad, you're a wealth of information.

Thank you all for contributing! I suppose I will buy that 20" bbl and if I need a little more mass to swing around I'll also invest in a 26".. But for now a 20" will suffice.. Now that I'm in school for the fall, I've taken on the "less is more" philosophy :D

Extremely grateful,


Brad Clodfelter
September 11, 2007, 07:06 PM

Glad to help.

When you get your barrel, try various Federal, Winchester, or Remington loads to see what patterns the best in it. If it's a Remington or Winchester barrel, I would bet money that 5 or 6 shot will more than likely be your best bet for shooting rabbits and squirrels. I would use 7.5 shot for doves. Stay away from your 1 oz 12GA factory loads in my opinion. The 1 and 1/8oz loads will give a lot better effective patterns with less holes to effectively take game. For squirrels and rabbits, I like a full choke tube. I have even used it for doves as well. It just depends on how close or high the doves are flying when choosing between a full or mod choke tube. Some may use an improved cylinder tube, but they are'nt worth much past 30yds from what I have seen.


September 11, 2007, 07:11 PM
Some years ago, the NRA's National Rifleman magazine Technical Staff did a study of shotgun barrel length.
The common thoughts were that a longer barrel shot "harder" and farther.

The NRA staff bought a Marlin Goose Gun bolt action shotgun with a 36" barrel and fitted a choke device to the muzzle.
The shot the gun for patterns and velocity over a chronograph, then cut one inch off the barrel, refitted the choke, and tested again.
They continued this testing and cutting off one inch until they got down to 12".

Their results:
Anything ballistically that's going to happen in a shotgun barrel will happen within 18 inches.

Anything over 28 inches and you actually start to loose velocity due to friction.

Patterning is a function of ammunition and choke, not barrel length.

Nothing "got out of hand" until the barrel was down to 12 inches.

Their conclusion was that the idea that longer barrels were better was a hold over from black powder days when longer barrels did produce better results due to the burning characteristics of black powder.

Brad Clodfelter
September 11, 2007, 08:13 PM

I'll go one better on your statement of patterning is a function of ammunition and choke, not barrel length. I would say optimum patterning of a shotgun barrel is soley determined by the best combination of matching your choke constriction to the backbore dimension. I think the test you were referring too and the Marlin goose gun wasn't a really a good test. For one, Marlin should have never called these longtom barrels goose guns. They really wasn't anything to write home about in how these guns shot vs other barrels from guns at the time. Also the barrel steel used will have some effect on pattern density. That explains why the older model 12 and 37 barrels shot so well and made good shooting match guns. From what I have seen in todays barrels, a longer barrel will provide an advantage in pattern density vs a shorter barrel. Each barrel may be different to an extent for how it shoots, but what I have found that Rem barrels will pretty much be standard for how they are made as far as dimensions from one barrel to the next of the exact same type barrel. I have yet to get my hands on a Remington barrel that would pattern #4 turkey loads at 90% patterns or better at 40yds regardless of the choke you use. They just aren't backbored big enough to shoot this size shot as well as a barrel that has a bigger backbored barrel like a Mossberg 835.

A lot of myths about how a shotgun barrel will shoot vs another barrel from another manufacture can and will be misleading especially if we listen to the manufacturers who make the gun. Remington will tell you that a larger backbored barrel is useless in their testing. That is a myth, and one that Remington needs to admit that newer Browning barrels that have the larger backbored barrels or the Mossberg 835 barrels have got their barrels beat when shooting various shot sizes. You won't notice this difference until you get to the bigger size shot of 4 shot or bigger. That's when you will see night and day difference in a bigger backbored barrel vs a smaller backbored barrel like the Remington barrels.

That is the truth as I have seen it.


September 11, 2007, 11:11 PM
I'll defer on this, since I'm NOT at all "into" shotgunning other than the 18" barreled defense type.

September 12, 2007, 01:30 AM
lol backboring, barrel steel metallurogy, this is getting out of my league--but the question has been answered, and this is fascinating regardless..


September 12, 2007, 01:43 AM
If you're looking for a simple "one shotgun for all uses", you might want to consider something like a 24" barrel equipped with a PolyChoke." That would handle just about everything pretty well, and no screw-in choke tubes and tools needed to fumble with.

I know a lot of people think PolyChokes are ugly, but they don't bother me at all, particularly on a nice pump gun. Just something you might want to consider. When the time comes for me to get back into waterfowl hunting, that's probably the setup I'll go with. Now that lead shot is verboten around here for waterfowling, my old SxS double is no longer of use for that.

September 12, 2007, 02:58 AM
Something else to consider--and consider it I will! Thank you Skeeter1


September 12, 2007, 05:31 AM
If there is no performance difference between a 20" barrel and a 28", why do most ammunition companies use only 30"+ test barrels to obtain their load data? Why is it that a given 12ga factory turkey load with a listed velocity of 1310 fps will produce a 5 round average 1306 fps from a 36" Marlin mod 55; 1225 fps from a 28" Mossberg mod 500 and only 1082 fps from a 20" Mossberg mod 500. Same loads from a Remington 1187: 30" bbl 1219 fps; 26" bbl 1104 fps.

September 12, 2007, 09:35 AM
Brad, how do the newer Browning (backbored) Gold shotguns compare to other shotguns on the market these days? Why do I ask, I am using Browning Gold shotguns for everything (pheasant, ducks, quail, and dove) and have had real good success. I normally shoot a 28" barrel but have one autoloader in 26". All my guns have the Invector Plus choke system so everything I buy is interchangeable. The Browning stuff may cost a couple dollars more but everything looks like it will last me a lifetime. Thanks.

Brad Clodfelter
September 12, 2007, 09:32 PM

Thanks for the question. All of the Browning Gold line with the backbored barrels as you very well know by now shoot mighty fine. When Browning first came out with these backbored Gold series shotguns, I believe they had a .747 backbore barrel. They have now expanded the backbore even bigger to around .755 I believe. They could go bigger yet like Mossberg has done with the .775 backbored barrel which by the way is the exact same backbore of a 10GA barrel and help the barrels to shoot even better on the bigger size shot. I would say that the bigger backbored barrels will help pattern density to some point even on the smaller size shot, but not to the same extent as with the larger size shot of #4 or bigger. I'm telling you I have seen the difference by testing Remington, Browning and Mossberg barrels with my own eyes using a bunch of different size choke constrictions, and I can honestly tell you that a larger backbored barrel is the way to go especially in shooting your larger shot sizes from 4 shot or bigger. My buddy tells me that the difference is even more noticeable in 2 shot or t shot or 00 or 000 buckshot. I would say he is right. I know of no 12GA gun on the market that will shoot #4 shot(which is what I use on turkeys by the way), any better than the Mossberg 835 with its bigger .775 backbored barrel. The Browning Gold barrels will shoot #4 shot better than your Rem or Win barrels, but not as good as the Mossberg 835. The Browning Gold 3.5 auto I had shot real well. I bought it for turkey hunting, but sold it after I found the Mossberg 835. I'm just a sole believer in using #4 for turkeys because I have seen what killing power they have on turkeys at 50yds or farther. But the Browning I had with #4 Win 2 and 1/4oz turkey loads and a .680 Carlson turkey choke would kill a gobbler at 50yds consistantly from what I seen shooting it testing it on paper at that range.

Enjoy your Browning shotguns. They are very well made and shoot great.


September 13, 2007, 10:14 AM
You guys might also bring up correct stock length for a new shooter and where you can get information on what that lenth should be. This could make a bit difference in how the shooter looks either at the barrel or down the barrel.

September 13, 2007, 10:37 AM

You are so right about the barrel lengths and velocity. Almost all of my guns are 20-24" equipped with Polychokes.

Skeeter, I love my Polychokes. The newer guns with screw-ins can be equipped with Poly IIs that can be screwed right in. With the older guns, you can have the barrel cut as short as you want and have a Polychoke soldered on by Polychoke.

So long as the gun is balanced, the barrel length makes no difference. I believe that 20-24' is the optimum length if the gun feels good and is balanced. I won't go any shorter because of muzzle blast.

As far as looks, I don't care. The Poly is so handy that I don't enter beauty contests. Try fumbling with those devilish screw-ins on a cold day and you will learn to like the looks of the Poly. I think they look fine and have them on all my guns.

September 13, 2007, 12:58 PM
Bare in mind that some trap and skeet ranges will not allow shotguns with a barrel shorter than 24". If I were you I'd keep the 18.5 for HD and buy a 26 inch with interchangeable chokes for everything else.

September 13, 2007, 05:09 PM
I'm not a shotgun guru but I have read that with the advent of smokeless powder, the use of a shoutgun barrel longer than 26" actually slows down the load due to friction from the wad on the barrel. Brad, you seem to know your stuff. Correct me if I'm wrong.

September 13, 2007, 06:35 PM
Shoestring, thats a great point! I'll research how the shotgun stock should fit me while I'm at it, thanks for reminding me :D


September 13, 2007, 07:14 PM

Optimum barrel length depends on the powder burn rate, the volume of the powder charge and the payload weight. As long as the pressure in the bore remains higher than the resistance of the payload, the velocity will continue to increase until the load clears the muzzle. The longer the barrel you have to work with, the more versatility it will provide in load building.

If a barrel length of 26" was optimum, why then do most all ammunition companies use test barrels that are 30"+ in length to obtain their load data? Scroll up and read my previous post under this thread.

Brad Clodfelter
September 13, 2007, 09:25 PM

I would say what I said above to be true to the best of my knowledge. A shotgun doesn't work the way a rifle will work in a longer barrel giving you greater velocity at least to a point in length when talking centerfire. The last test I read about stated anything over 18" in barrel length actually starts to slow down the velocity from a given load being shot. The reason being is excess barrel friction as you already stated. I would say these guys knew what they were doing when they conducted these tests. They seem to have their ducks in a row. Like I said, a lot of what we think we know has been passed down to us in false information from guys that didn't have their ducks aligned so to speak. The only way to really find out the truth for ourselves is to do some testing with different barrel lengths and loads to see it with our own eyes and not someone elses. I always said that seeing is believing as long as you are seeing it for what it truely is.


September 13, 2007, 10:25 PM
Here's just one example of the multitude of tests I have conducted. Results below were obtained using factory loaded ammo from the same lot, velocities taken at 10' from the muzzle.

12ga factory turkey load with a listed velocity of 1310 fps will produce a 5 round average 1306 fps from a 36" Marlin mod 55; 1225 fps from a 28" Mossberg mod 500 and only 1082 fps from a 20" Mossberg mod 500. Same loads from a Remington 1187: 30" bbl 1219 fps; 26" bbl 1104 fps.

If the friction was high enough to cause the payload to slow down before it cleared the muzzle, you'd melt the barrel down within a few shots. If you have a load that is slowing down in a bore over 18" in length, it's a seriously whimpy load on the order of a squib and would be totally useless.

You have to take every aspect into account when making statements about a given load or gun. A very light load of fast burning powder will suffice in short barrel but a heavy load of slow burning powder requires a longer burn time and longer burn time requires a longer bore. If a barrel is ecessively back-bored, gas leakage past the wad will cause considerable velocity losses. If the crimp on the hull does not provide enough resistance to movement, incomplete and or erratic powder burn will result. It doesn't matter if you are shooting a rifle or shotgun, if the load/gun combo is not matched to each other, performance will suffer.

Brad Clodfelter
September 13, 2007, 10:45 PM
I shouldn't have said a given load above. A turkey load would in all probability need a longer barrel to give optimum velocity. I need to find some good info on this shotgun shot speed vs barrel length. The last test I remember reading on the subjuect could very well be wrong. I personally don't know. I will try and find out more from guys who might know more on the subject than I.

FL-Flinter may be right.


Brad Clodfelter
September 13, 2007, 11:11 PM
I looked for some info on this matter we are discussing here about shot speed vs barrel length.

Click on this length below and scroll down to barrel length and read what it says.

I will do more searching.


September 14, 2007, 09:36 PM
Brad, Just so we're clear, I'm not jerking your chain with this ... truth is that there's a lot more BS out there than fact so this isn't personal. In the past year or so, I have hear/read at least six alleged "experts" still perpetrating the myth that blunderbusses were loaded with nails .... another thing is, anyone with a keyboard and internet connection can post to Wikipedia and it doesn't matter if what they posted is correct or not.

I find it interesting that the Wikipedia references Remington specifically when according to the email reply I received from Remington Ammunition a while back, all their shotgun ammunition data is collected using a 30" long test barrel.

Yes, certain powder/load combinations will burn all the powder within the 10-14 inches as stated in the Wikipedia article however certain powder/load combinations will burn all the powder before the wad clears the hull and still other combinations will continue burning well past the 20" mark. Yet another broad based statement based on extremely limited factors.

While we're talking burn time, truth be known, the actual burn time of the solids doesn't necessarily have a direct relation to the velocity gains or losses at the muzzle for a given load. Just because all the solids are consumed within a certain period of time does not mean that the gas stops expanding. After all, it is the expanding gas created by the burning solids that propels the payload and not the burning solids themselves.

Just pulling numbers out of the air here but let's say a given load produces a maximum working pressure of 11.9Kpsi. When you apply a time curve map to the equation, you may find that the maximum pressure reading is seen at ignition plus 0.008 seconds. Take the next step and you may find the solids are completely consumed at ignition plus 0.004 seconds. What this shows you is that even after the combustible solids are completely consumed, the pressure continues to raise because the gas produced by the combustion is still expanding at a rate faster than which the volume of the bore is being created by the forward movement of the projectile. Go yet another step further and say that the given payload requires a minimum of say 100psi to displace the air in front of it as it's traveling down the bore and to overcome the resistance between the projectile and the bore in order to maintain a given velocity. No matter how you stack it, if the pressure in the bore behind the projectile is greater than 100psi at all times, it maintains energy in excess of that required to overcome the losses thus resulting in the velocity of the projectile being proportionally increased for the duration of time it is contained within the bore.

Simply changing the crimp can have a dramatic affect on the performance. If your crimp is too light, the primer blast can cause the combustible solids to be displaced (scattered) in such a manner as to prevent them from being completely consumed. Likewise, the power of the primer can also have just as dramatic affect by itself for the same reasons.

Brad Clodfelter
September 15, 2007, 01:15 AM
Your probably right. I personally as I said don't know for I haven't tested shot speeds vs barrel lengths. If anyone has, I invite them to share their information here in more detail.


September 15, 2007, 06:18 AM
Here are some of the 12ga factory loads tested. These were all 2.75" hulls fired from a Moss 500 28" & 20" cylinder bore (no choke) barrels both with 3" chambers. One thing you will note is that the "Listed Vel" published by the mfg is quite obviously obtained with a real long barrel or just pure sales hype. (velocities are rounded to the nearest 5fps and are the average of five rounds)

Dram Eq. / Payload (oz) / Listed Vel. / 28" Vel. / 20" Vel

3.75 / 1.25 / 1350 / 1220 / 1070

3.75 / 1.5 / 1280 / 1240 / 1095

3.25 / 1.125 / 1335 / 1130 / 1010

3.25 / 1.0 / 1340 / 1200 / 1080

3.0 / 1.125 / 1205 / 1135 / 1040

3.0 / 1.125 / 1275 / 1150 / 1015

3.0 / 1.0 / 1310 / 1155 / 1005

2.75 / 1.125 / 1155 / 1075 / 960

2.75 / 1.125 / 1250 / 1165 / 1040

2.75 / 1.0 / 1200 / 1190 / 1070

September 16, 2007, 02:55 PM
Shoestring, thats a great point! I'll research how the shotgun stock should fit me while I'm at it, thanks for reminding me


No problem, let me know what you find.

September 16, 2007, 05:15 PM

Upon further research of shotgun fits, I found that my factory stock fits me great just the way it is--the cheek comb puts my eye looking straight at the bead at the appropriate angle, lop is optimal, and the stock fits my shoulder pocket like a glove!

The more I learn about this thing, the more glad I am that I bought the right gun for me :D


September 23, 2007, 08:01 PM
Awesome, now get out there and get some dinner!