Shotgun barrel length - how much does it matter?

[Butcherbill]

Brobee, can you post a closeup picture of the wad and slugs?

From your picture it looks as if Challenger is using a different wad now with the Gualandi slug ... but I would need to see a close up to be sure.

Anyhow .... I never got any accuracy with the Challenger Gualandi slugs ... and I always attributed it to Challenger's quality control.
At one point I found this in one of the Challenger boxes together with loose powder in that box. That round dit not even chamber ...

I’ve always had good accuracy from Challengers but I’ve yet to find any qc issues like in your pics, last time I shot them off the bench to dial in a red dot I was getting 3 of 5 pretty much touching at 50m

But I get it, every shotgun barrel is going to be different, they seem to shoot well in all the ones I’ve sighted them in for. Haven’t shot them further than 50 in quite awhile, 50m and closer is just my no go range if there’s a bear around.


I recovered 2 from the berm and was happy with how they held up.




This particular one would’ve been out of a 20” mod choked barrel, but both the 12.5” mod & 14” full choked barrels shoot similar.

 

[wai762]

I’ve always had good accuracy from Challengers but I’ve yet to find any qc issues like in your pics, last time I shot them off the bench to dial in a red dot I was getting 3 of 5 pretty much touching at 50m

But I get it, every shotgun barrel is going to be different, they seem to shoot well in all the ones I’ve sighted them in for. Haven’t shot them further than 50 in quite awhile, 50m and closer is just my no go range if there’s a bear around.
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I recovered 2 from the berm and was happy with how they held up.
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This particular one would’ve been out of a 20” mod choked barrel, but both the 12.5” mod & 14” full choked barrels shoot similar.

I thought you can only shoot slugs out of a cylinder bore ? or it one of those you can do it but don't do it too often thing ?

 

[The True North]

I thought you can only shoot slugs out of a cylinder bore ? or it one of those you can do it but don't do it too often thing ?

Improved and modified chokes are fine for soft slugs like fosters.

 

[Butcherbill]

I thought you can only shoot slugs out of a cylinder bore ? or it one of those you can do it but don't do it too often thing ?

People often say this but it’s not true, think of all the fixed full choke Cooey’s that have shot deer with slugs over the decades. It’s totally safe in any quality made shotgun.

Improved and modified chokes are fine for soft slugs like fosters.

You can shoot fosters out of a full choke, even harder cast like challenger’s are fine out of full choke’s. The manufacturer even lists it on their box, I’ve been shooting slugs out of choked barrels for years.

 

[The True North]

I thought you can only shoot slugs out of a cylinder bore ? or it one of those you can do it but don't do it too often thing ?

People often say this but it’s not true, think of all the fixed full choke Cooey’s that have shot deer with slugs over the decades. It’s totally safe in any quality made shotgun.

You can shoot fosters out of a full choke, even harder cast like challenger’s are fine out of full choke’s. The manufacturer even lists it on their box, I’ve been shooting slugs out of choked barrels for years.

You can. But they deform, and in my experience it has a noticeable effect on accuracy

 

[Butcherbill]

You can. But they deform, and in my experience it has a noticeable effect on accuracy

Not in my experience, when I pattern birdshot or buckshot I also shoot slugs. I start with open cyl and work up to full, there’s always one choke that give me good even patterns and poa/poi out to 50m. It’s always been mod, imp mod or full depending on my barrel, I’ve yet to find any choke under mod that improved accuracy with slugs.

 

[The True North]

Not in my experience, when I pattern birdshot or buckshot I also shoot slugs. I start with open cyl and work up to full, there’s always one choke that give me good even patterns and poa/poi out to 50m. It’s always been mod, imp mod or full depending on my barrel, I’ve yet to find any choke under mod that improved accuracy with slugs.

I have universally gotten the best, most consistent groups from 1oz foster slugs with cylinder bore barrels. Far and away the worst accuracy I've personally seen from slugs has been from full choke barrels.

I only shoot Federal slugs, could be the difference?

That's just my experience.

 

[Butcherbill]

I have universally gotten the best, most consistent groups from 1oz foster slugs with cylinder bore barrels. Far and away the worst accuracy I've personally seen from slugs has been from full choke barrels.

I only shoot Federal slugs, could be the difference?

That's just my experience.

Probably, I’ve always shot Challenger’s and Black Goose. Winchester super-x have been decent for low quality loads also. I’ve always found different brands of shotgun ammo to shoot different poa/poi out of the same barrels.

I’ve always found mod or full to give me the best all around accuracy for birdshot and slugs,

 

[Brobee]

Got out for some more frigid range time, starting out by running 28" and 30" wingmaster barrels....was super-glad I did as it reveals there is something off-trend about my new Fieldmaster production 26" barrel.

Also was worried that my 24" test barrel, being a browning Cynergy Ultimate Turkey, was somehow different compared to my growing collection of 870 barrels in ways other than length, so found and bought a new manufacture 24" 870 barrel made by Carlson's. It's actually stamped made-in-turkey, and unlike all my other barrels it is chrome lined. I re-shot all the 24" barrel slug trials (5 rounds each) and the results were statistically undifferentiated from the browning 24" barrel.

Still need to round out the bottom end at 8.5 inches and a couple more ammo-specific data points at 10 and 12.5, but the dataset is coming together nicely, as is the downrange velocity series too. Am excited for spring/summer to come so I can start the terminal ballistics work, still have to decide if it's worth the effort of testing the extreme high end at close range.

Hope you're all staying warm!

 

[Brobee]

**Post above EDITED AS FOLLOWS** it seemed totally wrong to me there would be a low velocity node for the 26" barrel, so I swapped it out for another new one I had on hand from resulting from a Fieldmaster-parts-stripping-adventure undertaken in recent weeks. After carefully cleaning it, I took the new barrel today and re-shot another complete series (5 rounds of each ammo type); lone-behold the data set plugged in almost perfectly with the trend you might expect!! So I've replaced my old graph above with one reflecting the new barrel.

Examining both barrels side-by-side to try and understand why one would be consistently 30FPS slower than the other one, a possible reason became evident - after running a bore snake through the new barrel, it pretty much wiped clean. After running the bore snake through the older barrel, there was still a TONNE of plastic and lead fouling along about half its length. It took some pretty serious action with a drill and chamber brush to scour the fouling out. Clean barrels matter (a bit) too.

 

[manbearpig]

Examining both barrels side-by-side to try and understand why one would be consistently 30FPS slower than the other one, a possible reason became evident - after running a bore snake through the new barrel, it pretty much wiped clean. After running the bore snake through the older barrel, there was still a TONNE of plastic and lead fouling along about half its length. It took some pretty serious action with a drill and chamber brush to scour the fouling out. Clean barrels matter (a bit) too.

When you're looking at FPS numbers between 1000-1500, 30 FPS is a significant (IMO) number and may motivate me to start cleaning my shotgun barrels properly.

I've always just run a cloth brush covered with a square of paper towel soaked with CLP through them to get the major soot out, and then chased it with another paper towel with a bit of gun oil (or gun grease for long term storage), but your findings certainly make a case for thoroughly cleaning a shotgun barrel.

 

[Ol' Flinter]

Get a copy of Bob Bristers' book ( about 1980) on everything to do with shotguns. He measured the change in muzzle velocity as a barrel is shortened 2 " at a time by actually starting with a 30" barrel and cutting it back 2" at a time, IIRC. The change will be most obvious as the barrel gets shorter when using slow burning magnum powders vs light target load powders that burn in the first 10 or 12" or so.

 

[Butcherbill]

Examining both barrels side-by-side to try and understand why one would be consistently 30FPS slower than the other one, a possible reason became evident - after running a bore snake through the new barrel, it pretty much wiped clean. After running the bore snake through the older barrel, there was still a TONNE of plastic and lead fouling along about half its length. It took some pretty serious action with a drill and chamber brush to scour the fouling out. Clean barrels matter (a bit) too.

I’ve noticed excessive plastic wad fouling affect shot patterns, so velocity loss doesn’t surprise me. I didn’t clean a 20” barrel for a couple years lol and all of a sudden patterns changed, I was shooting a fair bit of grouse with this particular gun.

Took a lot of work with a drill and a brush wrapped in steel wool and lots of g96, a dirt snake only did so much to it. Plastic wad came out in large flakes.

 

[MiG25]

The Challengers have never shot even decently for me and given the price I'll never buy them again.

 

[Brobee]

Super-shout-out to cgnner 257hunter, who made possible addition of a complete dataset for all slugs in the study so far with an 8.5in barrel:



Might re-shoot the 14” dataset with my mossberg shockwave and it’s cylinder choke - suspect the dip we see has something to do with my rem police 14” barrel’s fixed mod choke.

Was also surprised that the 8.5” barrel’s MV did not suffer as much as I was expecting. Also interesting is that the 8.5” dataset was obtained using a labradar which also collected downrange data, which at 100 yards was around a range of 700 to 800fps.

 

[0faustus0]

Brobee, looking at your graph another hypothesis might be that your 12.5 inch barrel shoots a bit "faster" for whatever reason ...

I guess I am wondering if it is the 14 inch barrel or the 12.5 inch barrel that is the outlier ....
???

 

[Brobee]

Brobee, looking at your graph another hypothesis might be that your 12.5 inch barrel shoots a bit "faster" for whatever reason ...

I guess I am wondering if it is the 14 inch barrel or the 12.5 inch barrel that is the outlier ....
???

Good point! I have another 12.5” I could try, but it is the same manufacturer and same lot as the first one. Will be fun to investigate, but my ammo budget is almost depleted…;(

 

[Brobee]

Spent yesterday in the glorious sunshine and melting snow, substituting some other barrels, adding another manufacturer's offering into the data set, then when back home put some effort into analysis and what I think is better presentation. Am curious where the upper-end limit is; will keep looking to latch onto one of those few factory 34" or 36" super-long trap barrels a guy sees every once in a while. In the interim, I feel like this is probably as good as the project's going to get for an indicative approximation of what's going on:



Will give the same treatment to the downrange velocity curves, then should be ready once the snow melts a bit more to attack expansion properties at different impact velocities.

Best,

Brobee

 

[supernova]

Excellent work, Brobee. I like the new graph format, much easier to seperate each load. I too was wondering about the dip in velocity for the 14" bbl data. At any rate, this thread pushed me over the edge and I have a brand new 14" Supernova sitting here and parts on order. I'm excited to get out and do dome more testing of my own and set this shotgun up just right. Years of dabbling with 870s, 500s and 590's and I'm finally back to the italian stallions.

 

[brybenn]

I remember playing with slugs for an entire summer using about 30 different 12ga guns of various lengths from 8.5" to 32" it was fun but I don't recall any numbers. I do remember hs6 gets a bigger ball of flames as the barrel gets shorter. I settled ultimately on a hard cast Lee drive 7/8oz slug over what ever amount of 700x my skeet loads were dropping. Been so long since I've looked at the bushing chart I can't recall the amount of powder. I just empty my shot hopper on my Lee load all and load the same load as my skeet loads just swap for the slug.
I used to shoot them into pails of sand on a running course I made. End of the weekend I'd reclaim the lead and recast the slugs. Kept the costs way low as 209 primers back then were 28.99/1000 and 700x was in 8lb kegs. Velocity was between 1150 and 1250fps over the complete spread of guns from 12.5-32. I never chrono the 8.5" didn't want to burn my chrono
I always got better accuracy with challengers and Rio stars and brennekes but not enough to justify the cost of factory ammo

If you'd like to try some Lee drive key slugs I can cast some up when I get a free couple hours to did out all my casting equipment