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idsubgun
December 10, 2011, 15:31
I have an extra ribbed 870 barrel I'm cutting down to 18 1/2" (or so), even toying with around 21"+ (so I can have 7 rds. in mag).

I have a couple other 870's with 18" barrels. I'm considering reaming and tapping them all for Rem chokes so I can change the cylinder bore to MOD, or even FULL, so I can hold smaller groups out further using 00 buck.

Also have my hunting 870 (28' bbl with Rem choke tube). So want to stay with Rem chokes. Rem chokes come in all the choke tube sizes I need, including a rifled slug choke tube.

Another modification I'm considering is reaming a long forcing cone into each of them to reduce recoil, and hopefully improve shot patterns.

Questions:

Has anyone tapped shotgun barrels (long or short) to accept choke tubes? Was it worth the extra effort on the shorter barrels? Anything I should watch for while reaming/tapping shotgun barrels?

Has anyone reamed a longer forcing cone into their shotguns? And was it worth the effort?

Does anyone have experience with rifled slug choke tubes? Accuracy? Etc.?

Thanks everyone!
Bill

ByronF
December 10, 2011, 20:15
No experience but would seem to be a physics issue with attempting to impart spin to such a heavy slug after it's already approaching mach 1. Very different from imparting spin whil accelerating down the bore. Not saying they won't shoot accurately enough but I would be skeptical of whether it would be any more accurate than a smoothbore without a choke. It's a very interesting question you ask.

Some may counter that if the choke didn't do anything they wouldn't make them. However, lack of function never prevented the old lead Forster slugs from having "rifling" on the OD of the slug. And they sold plenty of them.

FUUN063
December 11, 2011, 00:04
I have oft considered buying the reamers and taps for doing such work. They are expensive and it would seem that the ones that I want would be different than the ones people would want such as Winchokes, Browning, etc. So, I never bought them. I would still like to purchase the Remington tooling, though.

As far as the rifled choke tube, the above has always made sense to me, but who am I to say they don't work. The only thing I know is, I have cut many hundreds of barrels off to make them shorter over the years. I have seen two where the owners swear they had longer barrels with the rifled choke tubes installed and when they bring me their barrel, the end is split back a little ways and now they want it modded to be around 18" because it apparently "blew up". I don't know how true this is, but I do know the barrels were blown up at the very end and they were threaded for a choke tube. Who knows?

Leland

DrBaboon
December 11, 2011, 00:45
Tried what you are talking about, and used it for quite a few deer seasons.

My experience is limited to overlap between the barrel/rifled choke project, and the load-my-own slugs project.

IOW - I have not had a fully rifled shotgun barrel available to compare what I am getting with my slug loads.

I called it day when I got better groups with my slug loads and screw in rifled choke than I was getting with factory rifled slugs in a smooth boare. Most of my sight in and fooling around is at 50 yards. I like to hit 2-3" high at 50 yards.

All that I wanted was a repeatable load, with a predictable drop, that gave me acceptable hunting accuracy and groups.

How good is the combination of hand loaded slug and the rifled choke compared to a high dollar factory sabot slug and fully rifled barrel? Beats me - have not had the chance to try that. And like I said, I have not even had the chance to compare my slug loads between the rifled choke and a fully rifled barrel.

On a good day I can probably hit a 3" paste on target at 50 yards with as many shots as I bother taking. It's a lot better than I can get with a cylinder bore and a rifled slug.

I'm using 1 ounce 12ga slugs that used to be sold at the Mountain of Geese, with AA wads for sabots. It's one of those 3" choke tubes with slow rifling (not sure - might be 1 in 48").

The main thing I've needed to pay attention to is being religious about using moly anti-seize grease on the choke tube threads, and breaking the choke tube free before coming home from hunting. Don't even remove it, just make sure I can break it free after firing 2-3 or whatever number of slugs I need for deer on that trip.

The rifling ends up tightening the tube into the barrel with each shot.

Just like you are starting with, I used an off-the-shelf ribbed barrel, had it cut down, reamed/threaded for screw in chokes. I put rifle sights on the vent rib, and shoot iron sights.

I don't think I've ever had a shot on a deer that was more than 80 yards. I know the drop on my load to 125 yds.

It reliably puts deer in the freezer. I haven't seen any reason to change what I'm doing with the rifled choke or the load.

tdb59
December 11, 2011, 10:28
I have installed choke tubes in several shotgun barrels, mostly standard Tru-Chokes, and the only major issue is barrel concentricity, and barrel thickness at the location of the threads. I use reamers and taps with bronze pilot bushings, and make the cuts in the lathe in back gear.

I do not know if Cation is still in business, but I have used their EDM rifled choke tubes, and with plain Winchester hollow base slugs, and a bead sight, put 3 rounds into an overlapping cloverleaf at 50 yards. This is in effect the same technology as the Holland and Holland Paradox guns.

Being as the results were all I wanted and more, I did not pursue any other loads.

idsubgun
December 11, 2011, 16:34
Well, my goal at the start of this whole project was to tighten up groups on short barreled shotguns. To achieve this, I was thinking of choking the muzzle, and reaming a long forcing cone in the breech end.
The slug choke was an afterthought. Saw the slug choke when I was researching the different types of chokes.
Not having a bunch of experience with choke tubes, I was wondering if slugs could be fired thru shotshell choke tubes, and is there a recommended size limit? As in "okay with MOD chokes, but not with FULL chokes"?

If I decide to go any further with this, I am sticking to Rem chokes. Mainly because I have a 28" barrel bird gun with Rem Chokes, and they are abundant...cheap! They almost give them away at gun shows.

As for the cost, I'll either eat it and try to recover by offering those services.
I haven't checked, but you may be able to rent the tools, like you can chamber reamers.

Thanks! Would love to hear further discussion...especially if I decide to buy the tooling. Expensive!! :eek:

Clark
January 11, 2012, 04:00
http://i757.photobucket.com/albums/xx220/ClarkM/ShotgunThreMetroChokesAddedDSCF0103-1.jpg

I got some shot gun barrels for very cheap off Ebay, back when they allowed barrels.

I cut for a rem choke on the muzzle and I cut like a choke tube on the breech.

Then I screwed some end to end, to make a shotgun quiet.

kotengu
January 11, 2012, 09:03
I had Ed Vandenberg do the work for me, so I can't help you with the method. I can tell you that the particular barrel I cut down to 18.5" didn't have enough wall thickness for RemChokes, so he had to thread them for thinwall chokes instead. They're a little harder to find, but hey - you only buy them once.

He also lengthened the forcing cone while he had it. I don't have any scientific evidence, but I am happy with the work. I wouldn't say the recoil is noticeably less, but that's a hard thing to quantify. I do think the patterns are better, and the flexibility of changeable chokes is worth a lot to me.

Everything I've read says typical slugs through anything tighter than an improved cylinder choke is a no-no. Reports range from poor accuracy to damaging your barrel, so I haven't tried it. Bulk Remington slugs from Walmart gave me the best groups with an IC choke, so I stick with that.

WWHD116
January 28, 2012, 05:32
I would recommend a Hastings Extended Length rifled choke tube. I have one for my Benelli M4 and a Remington 1187.

It adds approximnately 10" of rifling, ( 1 in 34 twist i think) and extends the length of the barrel by about 8". I have excellent results with Sabot slugs and Brenneke type ( with the attached base) slugs. I haven't tried any foster hollow points in it yet.

Hasting is out of business but you can still find some of the NOS choke tubes on gunbroker. GB is where I got the one for my 1187, and I think it was like $40.

The tube for the benelli was very hard to find, after 6 months of looking I found one from a company called Kebco llc. They have new ones available for $85 each.

You wont be disappointed with a Hastings extended length choke tube, as long as you don't mind an extra 8" to your barrel. Its the best compromise between a smoothbore and a rifled barrel IMO.

olgier
January 28, 2012, 07:48
I learned a long time ago that the best way to shoot slugs is out of a fully rifled barrel. I also learned along time ago that buckshot totally SUCKS for actually shooting deer unless they are 10 yds or less away from you.

I wouldn't choke a short barrel for slugs. I would choke one for birdshot though.

Deltaten
January 28, 2012, 08:49
Wouldn't the slug choke tube be "cylinder bore"??? IOW; a thread protector for when not using restrictive choke tubes?
I get 4MOA or less w/my Rem870 20" smooth-bore and hand-cast sabot slugs. No rifling needed ;

gunplumber
January 28, 2012, 10:47
There is no 18" choked barrel. You can get them in 20". I've done several in the past. I did some testing about 20 years ago. I found no significant difference in accuracy between a slug barrel and a rifled choke. Nor between a rifled choke and a Brenneke Rotweil.

So my recommendation is to just cut it at 18 (to the bolt face, not the end of the barrel) and use the Brenneke slugs

I'm contemplating now doing it on a 20g