I was looking at the Retay website because a local store has a Retay GPS shotgun on sale. They show patterns on targets and say "them" and "ours". Then they show why their barrels are better. It looks like they have a lengthened forcing cone (I think it's called).

So my question is why does anybody still make barrels that aren't overbored, lengthened forcing cones, etc? Like the mossberg 835 that has a full 10 gauge bore on a 12 gauge gun. The only downside I see is supposedly you can't or shouldn't shoot slugs. What happens if you do?
At the time of manufacture it wouldn't cost any more to just use different tooling to actually make really good performing barrels. It just seems really antiquated for any company to still not be doing this stuff.

When it comes to the Forcing Cone there is no actual specific measurement for a lengthened FC vs a non lengthened FC. Years ago, when the majority of wads were cardboard, a “short” or quick transition from chamber to bore diameter was needed to minimize any gas blow by. The advent of plastic wads allowed the wad to expand to the bore diameter and seal and longer FC did make for better patterns just like the Retay ad claims. While gun makers were originally slow to change today you will find that many decent shotguns have a forcing cone as long as it needs to be, even the  ubiquitous 870 barrel of the last many years have a longer cone than they did in the 1970s and 80s. In other words....Rertay is NOT the only gun maker with a factory lengthened forcing cone...and not all forcing cones need to be lengthened more these days...many are already as long as they need to be.

It's pretty much marketing hype.  There is no way for the vast majority of shooters to determine any benefit.

Improving patterns for Turkey is something every Turkey Hunter will benefit from.

The problem is "better" isn't always better. Sometimes it's pure marketing, sometimes it is better for certain things. The so called improvements are never better for everything.

What is a "lengthened forcing cone"? Lengthened compared to what? In reality length doesn't even matter. One of the shortest forcing cones you will see is the Mossberg 835, yet the angle is the same as a 500 with a much longer forcing cone. According to SAMMI, their drawings for 12 gauge show their spec for a forcing cone is a 5 degree angle, with a -4.5 degree tolerance. A Clymer "long forcing cone" reamer is 8 degrees. I've even heard of special target guns with no forcing cone, just a straight taper all the way to the choke.

Now most manufactures seem to be in that ballpark 5 degree mark, you would have to ask them what they use, I don't bother to cast my shotgun chambers. There's a reason not too many have bothered to stray too far from that, and that is there's no reason to do so.. Nobody has scientifically proven a certain forcing cone angle produces a tighter pattern. The potential with a shallow angle forcing cone is blow by. One of the marketing aspects was recoil reduction, which it obviously has no way of doing that except maybe one, and that is reduced velocity. Not exactly a good trade off if you ask me, just use less powder if that's what you want.

Bore diameter is a whole different deal. It does make a difference, but it also comes with real tradeoffs. Bore diameters are what they are from hundreds of years ago. All of the chambers were designed for those bore sizes. All of our shells and wads were designed for those bore diameters. All of our slugs and buckshot were designed for those bore diameters. There is some leeway, a Benelli .721" bore doesn't make a huge difference vs a standard .729"/.730" 12 gauge bore. The bigger the bore, the more potential velocity you can get, that's one of the biggest advantages to the larger bores. This is because at the same pressure, you have a larger area for that pressure to work, think a bigger piston. The downside is when you go to big, you start to loose fit. A birdshot load in a plastic wad with a good sized gas seal is fairly tolerant. Anything else, smaller gas seals, or non-plastic wads, nitro cards and fiber wads and such, and they do horribly. Not just in lost velocity, but blowby can absolutely destroy patterns. The other downside to a larger bore, if too large, is you have now given up any hope of accuracy with slugs. Certain slugs, such as rifled slugs are kind of tolerant to a certain point, but once you start getting up there, there's just no way they can ever shoot good. On the other side of the spectrum is undersized bores. Some claim they shoot slugs better, but that's up for debate. The Mossberg 835 uses a 10 gauge barrel with a 12 gauge chamber. It's great because it gets you closer to 10 gauge performance in a 12 gauge shotgun. It's bad because besides shooting birdshot in a plastic wad, such as steel shot, which is it's purpose, it's only downsides for everything else. Personally I feel like if you want a 10 gauge, get a 10 gauge.

Chokes is an area ripe with marketing with little data to back up the claims. In reality, the only thing that matters that much is the constriction. It doesn't matter what it says on the tube, it's the bore diameter, minus the ID of the smallest part of the choke that is the constriction. Beyond that, the different taper lengths, parallels lengths, porting, ribbing, wad stripping (which is not a real thing), none of that does much of anything. Some choke tubes don't have any of that, they are just a straight taper from entrance to exit and they do as good as any. Fixed chokes performed just as good as choke tubes.

Some companies get sneaky with the advertising too. Vang Comp is bad for it. They give a list a mile long why their barrel pattern buckshot tighter than most cylinder bore barrels. It's because theirs isn't a cylinder bore barrel. They do all that fluff, but in reality what they do is backbore the barrel, and leave a fixed choke on the end. You could likely get the same exact result by threading the barrel for choke tubes and putting in an IC or modified choke tube.

I never said they wont give good results. What I said was they won't strip a wad. Its traveling whatever, 1200 fps at the muzzle, maybe 3000 psi of pressure behind it. A little ridge isn't stopping squat. They don't perform any better than a normal choke of the same constriction.

Are you saying that the wad is not being slowed down enough to make a difference?

Or

Are you saying it isn't being slowed down at all?

Wad stripping chokes do not slow AHNYTHING down at all.

I don't see why people would be in disbelief. Straight cylinder bore is a great choice for skeet. Most probably shoot improved cylinder, but it's not that different.

What do you mean by -5? That means nothing to me. I looked at comp n choke's website and I don't see it there either. I do see they offer a negative choke, -.005" constriction (so maybe better said .005" dilation?), maybe that's it? It does nothing, it's the same as a .000" cylinder bore. Obviously being larger than bore diameter, it's not even a "wad stripping" style choke at that point.

I use a Remington Straight Rifled Super Full Turkey Chimr for everything except waterfowl.

It isn’t made anymore, and they sold for less than $20 way back then.

On the undersized bore, how far would be safe to go? For example, on a .410, would a .400 rifled barrel possibly work well for slugs? My understanding is foster slugs are rifled so they can swag down a choked barrel which is somewhere around ~ .398. So, would a .400 rifled barrel likely be okay?

I really don't know what the limit would be, I'm not the right person to ask. SAMMI says 410 bore is .410" +.020" tolerance. So it could be .410" to .430" and be in spec. These are voluntary standards though.

I actually threw around the idea of a rifled 410 "shotgun" back when a lot of states had shotgun deer seasons. I still hunt southern Minnesota, which is about the only state left with a significant shotgun zone, but even that is likely going to be eliminated soon. Minnesota is extra stupid because they have always allowed rifles in the shotgun zone, it's just that they have to be "pistols". A TC encore with 15" barrel in 308 Winchester is perfectly legal in their shotgun zone as long as it has a handgun grip or brace. AR pistols are also legal.

Anyway, what I was going to do is get a custom chamber TC Encore barrel with a 44 caliber barrel, and chambered for 2 1/2" 410. I was going to use 9.3x74r brass and load 44 caliber bullets in it. The thing that stopped me was Minnesota being dinks as usual, I could not get their answer on what their definition of a slug gun was. I would have a rifled barrel, chambered for a shotgun. 410s are legal there. The only thing was the brass would not say 410. I finally called the local CO, and he angrily answered "how did you get this number, what do you want?" Dipshit, you are a CO, you're all in the regulations book. I decided if my local CO was that big an asshole for no reason, I didn't want to give him a reason.

I disagree with you about how Vang barrels work.  I have tested them side-by-side after modification.  Buckshot does not act the same through a choke as it does with a back bored barrel.  
He does get very good patterns from his barrels--with buckshot.  The smaller the shot the more easily it can be "rearranged" during constriction.  End choking buckshot causes fliers due to inter-pellet interference.  

Vang may not see as much difference these days because manufacturers have adopted his practices.  But his barrels are still excellent buckshot barrels.  


ETA:  I don't know if any of this makes any difference now the Flight Control wad is a thing.  This was back in the day, when we did not have such marvelous things.

Vang comp barrels are end choke barrels. They simply do it by back boring the barrel, and leaving a fixed choke on the end. The porting they do does not effect patterns, but it can be a helpful feature for recoil control. For purely patterns though, a choke tube will accomplish the same thing.

Thanks for your reply. Anyway, the reason I asked, is I have a couple of the AR 410 uppers and I was wondering if there'd be an easy way to add a rifled barrel. I noticed there are .400 legend barrels available for the AR platform. There are also .450 bushmaster barrels. But I thought a .450 barrel might be too large as the slugs might not engage the rifling. I guess if you were going to load your own slugs as you mentioned, that wouldn't be an issue. Anyway, I was thinking if it might be possible to use an off the shelf, rather than custom barrel and simply have the chamber reamed out to accept .410 shells and use  existing .410 slugs. However, I guess if you were going to go to that extent, you might as well go with a custom barrel and custom loads as you were thinking.

Yes, I don't really see a path forward for an AR in 410. I don't know much about them. I'm not one of those that thinks 410 slugs are useless, I regularly see the work of my great uncle who shot plenty of MN bucks with a bolt action 410 and slugs. Still, in my opinion, a 410 rifled slug is not going to be a great choice beyond the range they are accurate enough from a smooth bore. I don't see any way to make a 45 caliber work either. A plastic or paper case is pretty much topped out with a .410" slug or bullet. A brass case holds a 44 caliber bullet. The OD of a 410 shell is dang near 45 caliber. If I were to stick with 410 plastic shotshells, I would try to use a 40 caliber barrel, and load 40 caliber bullets. They are going to be a little loose in the shell, but I think it would be ok. A cast bullet of say .403" isn't that much smaller than a rifled slug.

In my opinion, the only way to go is to full on custom 44 caliber and brass case, otherwise it's not worth it.