Slug and Rifled Choke Question

[barnabus]

I have loaded up some Lyman 525 slugs over 23.0 unique powder and a F114 wad thats found in the 5th edition. i purchased a Carlson rifled choke tube for my AR12. what has been yall experience with slugs/wad combo out of a rifled choke tube? Anything i need to know.

[centershot]

My experience with a rifled tube is limited to my 870 but it was much better than I ever expected! A couple of years ago I worked up a load for my M500 w/ rifled barrel, that load would put 5 shots into a jagged 2" hole at 50 yds. I tried that same load through the 870 with cylider, IC and Mod tubes with no success. I bought a Carlson's rifled tube and that same load would hold a 3" group at 50 yds. I have to admit that was better than I ever expected. I didn't think slamming a full speed load into rifling would be anything but a failure, but, that tube was money well spent!

[W.R.Buchanan]

The British Big Gun makers of 100+ years ago made Guns known as "Ball and Shot" guns under the Moniker of "Paradox." These guns were designed to be a "one gun that does it all," for those venturing into the Dark Continent. They were 12,10, 8 and 4 Gauge Double Barrel, Side by Side Hammer Guns, and they had Rifling for the last 2-3" of the barrel before the muzzle. Much the same as the Rifled Choke Tubes of today.

I recently ran across a Gun's & Ammo Magazine which was one of the first gun mags I ever bought when I was 13 years old. (59 years ago!) It has an Evans 8 Bore Fully Rifled Double gun on the cover and a story about it inside. The article was actually about two guns, the Evans Double, and a H&H 8 Bore Paradox Gun.

The Evans gun was purportedly owned by "Bwana Cottar" who was responsible for taking several hundred African Elephants with it. It was kind of a Plain Jane working rifle, however the H&H Paradox gun was a fully engraved work of art! They weighed between 16-18 lbs! and the recoil of a .460 Weatherby was said to be "Positively Soothing!", compared to these guns ! I can only imagine.

It shot a 1250 gr slug fueled by 14 drams of Black Powder and it took a real man to pull the trigger. There was one group posted in the article that was shot with the H&H gun, 6 shots at 50 yards ,3 left and 3 right, that measured 1 1/4 x 2 1/2" with the left barrel shooting a cloverleaf and the right slightly bigger. With a bore of .835, those are pretty big holes and the accuracy was much better than was expected. Note: Once again rifling for only the last 2-3 " of the barrels on the H&H gun which shot the record.

So in answer to your question about Rifled Choke Tubes, it would appear that it can be an accurate method of increasing accuracy of Shotguns. I am about to find out with some MP/Lyman Sabot Slugs I have loaded and I also want to try some of my STI Slugs which are designed for Rifled Barrels to see if they will work. We'll see.

Randy

[longbow]

Randy:

They weren't just plain shallow rifled, at least the H&H Paradox gun used Fosbery's ratchet choked rifling:



Actual dimensions seem hard to find, or at least I haven't found definitive info but have read that smoothbore diameters ranged from 0.735" to 0.745" and the lands of the choke were as small as 0.690" so a tight squeeze!

A view from the muzzles:



Definitely deeper rifling than in a typical rifled choke tube! The idea was to grab the Kynoch slug, squeeze and spin without it stripping:



I'm guessing the narrow driving bands allowed for easy squish and the design allowed for lead displacement with the tight squeeze.

I e-mailed H&H in London and was contacted by the London gunroom manager who was quite helpful but he didn't have any technical info on diameters and twist rates. He said the barrel makers just used the original tooling as it was.

Ross Seyfried wrote an article about his Paradox gun and IIRC he said the rifling twist was 1:36" which seems awfully fast to me. The round ball guns ran very slow twist of about 1:100" for 12 ga. round ball. The Paradox slugs are not a lot longer than they are in diameter so wouldn't require fast twist.

I have a rifled choke tube and adapter but haven't put it on a gun yet as I want to use a cheap donor gun to test it on before trying to silver solder that adapter to my Mossberg Slugster. I don't have any guns threaded for choke tubes or I would have tested it by now.

I have read very polarized comments about the rifled choke tubes. Some say they shoot like a rifle and some say they don't help much if at all. I suspect that fit is king as always and those that have bore diameter slugs or a sabot slug that fits the rifling well have better success than those that just shoot anything through the rifled choke tube.

I have been anxiously awaiting your rifled choke tubes testing because you know what you are doing so I will believe your results. That might spur me into action either getting barrels threaded or the adapter installed. I can't afford the £130,000.00 H&H wants for a real Paradox gun!

https://hollandandholland.com/guns/the-paradox-gun

I have to make do with what I have!

Longbow

[W.R.Buchanan]

Kent: Your pics were greatly appreciated! Especially the one muzzle on, as it really shows how deep that rifling was. You can see that the Paradox Slugs had ample room for Lead Displacement so deep rifling would certainly bite and spin the slugs. The grooves look like they are a faster twist than the Carlson's Choke Tube..

So on the Carlson's Rifled tube I have the Grooves measure .729 and the Lands measure .710. so that means the rifling is .010 deep on each side! Which is a lot deeper than I would have guessed. But wait,,, At the entrance to the tube the grooves are .742 and the lands are .738? So this thing is Choked/Tapered, as well as being rifled. So in the end the grooves go from .002 deep to .010 deep! Go figure?, and obviously we don't know what they were thinking when they designed this thing?

Maybe I'll call them and ask?

Oh, and that H&H Paradox was L130,000 plus VAT!

Randy

[longbow]

I'll have to check mine Randy! I drove a 0 735" ball through it but didn't notice a change in groove depth or any angle to the lands. Resistance to driving the ball through seemed consistent but then I wasn't looking for anything but engraving on the ball.

I'm pretty sure mine just says groove diameter is 0.730" with no other info... also Carlson's. Of course groove diameter would be better at 0.728"/0.729" or even tighter and with deep rifling. A full bore slug might not strip too easily but a wad slug is a different story. The wad has to grip rifling and transfer the spin to the slug so fit must have to be pretty tight.

I'll check mine for diameters tomorrow. Now I'm curious!

Longbow

[missionary5155]

I have enjoyed reading this fine fact filled thread !
My thoughts at this moment are...Why try to improve on what worked 140 years ago ? Those barrel makers had access to Projectile protectors... Paper patches and they went full bore with good results. A fine working compromise for the task.
At the real ranges of need... 50 yards and usually closer to under 30 yards, the system worked.

I do think a progressive full rifled barrel is the best answer (Pope and others).
We have 2 Hall rifles. One a 1819 flint and a 1836 percussion made at Harpers Ferry Arsenal. Both have progressive rifling and shoot lubed naked RB fine. This is a Beach Loader. The military used a Paper Cartridge. But I load from a measure and use a snug fitting .54 40-1 RB. Groove is .54. Lands are about .52. At 50 yards they both shoot nice cloverleafs with me sitting on the back side.
But building the rifling rig would have to be far more complicated.

But I am reading and do enjoy it all.

[longbow]

To try to stick to the topic of what you need to know...

Several people have posted that their choke tubes tightened up so much they either had trouble removing them or had to get a gunsmith to remove the choke tube.

Use a good choke tube lube is the moral of that story!

Petander posted recently that he used Hi-Tek Aqualube with good results:

https://castboolits.gunloads.com/sho...eize-Very-good

Longbow

[Petander]

I have a Carlsons rifled choke for a 20 gauge 870.

With my limited 2 years rifled choke experience I've noticed slightly better grouping with Round ball / wad -ammo, compared to any or no plain choke. I have two ball sizes, a tight fit is better. I get 6" / 75 meters with my "Economy RB:s" , factory trap ammo cut open, remove shot,add a cork and a round ball. Roll crimp while squeezing tight.

It's okay plinking ammo up to 50 m for me.

I do get better results with fullbore slugs like this Zveroboy, a typical 25 m group, fired standing with a red dot / 20 gauge 870. I'm only in the beginning of testing these further out from bench, a 12 gauge fullbore / fully rifled barrel madness caught me. 20 has been on standby...

I think fit is king here,too. And how the wad grips the slug to spin it, my coated slugs/balls may not have the best grip...

Fullbore has less variables.

Here is rifled choke 25 m standing. Fullbore Zveroboy.

[Mr Peabody]

I have loaded up some Lyman 525 slugs over 23.0 unique powder and a F114 wad thats found in the 5th edition. i purchased a Carlson rifled choke tube for my AR12. what has been yall experience with slugs/wad combo out of a rifled choke tube? Anything i need to know.

I've had good results with a wad combo that measured .730 or greater. Less than that didn't work so good, Carlson's says their choke tube is set up for .730 or greater

[Hogtamer]

The older I get the more attractive the 20 ga becomes. Nice job!

[centershot]

To address a couple of questions brought up in the thread;

Fit - In developing my 12 ga. sabot load with the M500, nothing good happened until I went over bore size with my payload. I'm loading a .662" RB in a Federal 12S3 wad which mikes .717-.718". I added a coiled paper strip .011" thick around the ball to bring the OD up to .739". Instant success! If you're running a sabot-type load you need to squeeze it pretty hard.

As far as choke tube lube, I use the same aluminum-based anti-sieze compound that I use on my inline muzzle loader. Haven't had a problem yet with an overly tight tube. You can buy a lifetime supply at any auto parts store.

Mike - I hope you treasure those Harper's Ferry riles (I know you do!) as much as I wish I had one! They are a beautiful piece of work! Keep the faith, Brother!

[missionary5155]

Howdy Centershot
Yes we are blessed to have them for these years. The years we have traveled our country visiting churches has also been used to visit the local shops. Some have held treasures we never expected that the local population had no interest in. We are blessed !
While we are down here in Peru they are on display at the Vermilion County War Museum, Danville, ILL-ois. Most people have no idea what they are.
But when we are up there the 1819 model flintlock goes out with me. The 1832 cap-lock is in very nice condition. But the flintlocks are far more interesting to me.
But I wander off the trail here.

[longbow]

So, I mic'd my Carlson's 12 ga. choke tube I bought for the Mossberg Slugster. It is a standard rifled choke tube, not an extended one or at least not as extended as I have seen some to be. I did not see any extended rifled choke tubes for Mossberg on the Carlson's site when I ordered mine.

In any case, I drove a 0.735" RB into each end of the choke then mic'd the lands on the balls (choke groove diameter) and got:

- muzzle end: 0.729"
- butt end: 0.733"

So if I measured correctly that means about 0.004" larger diameter at the butt end.

I tried as best I could using a vernier to check groove diameter on the balls (choke land diameter) and got:

- muzzle end: 0.718"
- butt end: 0.726"

So, 0.008" larger land diameter at the butt end. No surprise here because there is a taper machined into the choke tube entry so there is a machined taper to the lands. I drove the ball in past where I thought the machining ended.

Then I used a Starrett telescoping gauge and micrometer to check choke tube diameters. I got:

- muzzle end: 0.727" groove; 0.719" land
- butt end: 0.734" groove; 0.732" land (I thought I was below the machined taper so maybe the land/groove depth is tapered?)

So from that it appears that the groove diameter is slightly larger at the entry /butt end of the choke tube but rifling depth is about 0.0055" deep max. ((0.729" - 0.718")/2 = 0.0055") It looks shallower than that to me (I'd say more like 0.004") but that is what the measurements say. The rifling in my choke tube is certainly not 0.010" deep!

If the grooves are tapered I am not sure how they would accomplish that unless the choke tube was cocked with respect to a single cutter and choke tube revolved as each groove was cut.

Maybe Carlson's has changed their rifling method? It certainly appears that mine is much different than Randy's. I bought mine a couple of years ago... and it still sits waiting for me to pick a gun to silver solder the adaptor to!

At this point I'll wait to read about Randy's results before adding a rifled choke tube to a gun. Petander's results look good though so...?

Longbow

[missionary5155]

With those diameters I wonder... Are they hammer forging those rifled tubes ?

[longbow]

The bore is smooth without obvious machine marks but grooves look to be cut with longitudinal striations as a cutter would leave in them.

I'd say cut rifling from what I see.

Longbow

[W.R.Buchanan]

Kent: I measured my choke tube with Dial Calipers and it took me a few times to get repeatable readings. I was amazed that the rifling at the muzzle end was .010 deep! but also surprised that the entry end was so shallow and started out bigger .742?

Randy

[longbow]

Randy:

Mike brought up a good point. I am quite sure my choke tube is machined smooth to ID. whether bored or reamed then grooves cut.

Does yours look like cut rifling? I guess at 0.010" deep it would have to be cut or possibly hammer forged as Mike asked.

Longbow

[Cap'n Morgan]

The obvious way to cut rifling over a short length would be with a full profile reamer in a single pass (Uberti does this on many of their barrels)
but that would not explain the taper, unless the choke is "squeezed" slightly on the middle in the holding jig during reaming.

[barnabus]

here is the results from 30 yards with the Lyman 525 slug with 23.0 grains unique with f114 downrange wad and carlsons rifled choke. Mounted is a Burris Fastfire 3