Home Forums Hunting & Shooting Gunsmithing Opening up a fixed choke shotgun

I was at a gun show today, and found a beautiful little B C Miroku O/U that I almost took home.

The problem is that is is choked Full and Full. Probably a great duck gun back in the days of lead shot, but not so practical now.

Does anybody have any suggestions on who to send it off to to get it reamed a bit? I'm figuring to maybe to I/C and Mod or so? Or maybe I should just go ahead and spring for getting it threaded for tubes?

Ballpark figures on cost?

I know Briley can do it, but ouch....

http://www.ahlmans.com/shotgunalterations.html is a little lower than Briley's. I put a Browning A5 on layaway today and I was comparing prices.

An older Miroku probably has barrels to thin to tube with anything but Briley Thin Walls, if it can even take them. I use a Sunnen Honing Machine to enlarge choke diameters in fixed choke barrels. It's pretty quick and easy to control size and finish. Most all quality automotive machine shops have one and if you know your desired choke diameter I'm sure could oblige you.

Scott

Here again the caution flag must come out. If the person opening the choke isn't absolutely careful in aligning the cut to the bore, the column can stray enough to crate serious holes in the pattern resulting in misses. Because there is no practical way to adjust a shotguns point of aim using sights, shotguns rely heavily on precise bore/choke alignment for accuracy. So be careful!

I've opened up some chokes on shotguns with hones sold by Brownell's, IIRC.
As Malm mentions, you just need to be careful when doing it, so the shot from both tubes go to the same POI.

Mike Orlen in MA will do it for $35 TO $40 a barrell. Look him up on Shotgunworld.com.

79 Salem Street � Amherst, MA 01002 � (413) 256-1630 � fax (413) 253-5665
michael.orlenverizon.net
Shotgun Barrel Services Offered:
Dealer List
Choke Tube Installation (per barrel) $35.00 $55.00
Cut Single Barrel (to rib post) Reset Bead N.C. $15.00
Cut & Fill Double Barrel (reset bead) $35.00 $45.00
Furnish & Install Center Bead $10.00 $12.00
Install Sun Spot, Raybar or Bradley Bead $10.00 $15.00
Lengthen & Polish Forcing Cone & Chamber
(10, 12, 16, 20, 28ga. & .410) $35.00 $55.00
4 inch �Super Cone� (12 ga) NEW!! $45.00 $65.00
Adjust To More Open Choke $35.00 $45.00
Jug Choke Barrel (12, 16 or 20ga) $60.00 $85.00
Port Barrel $45.00 $65.00
Install Permanent (soldered) Choke Sleeve $75.00 $95.00
Drill & Tap Shotgun Receiver (includes Scope Base) $45.00 $65.00
Stock Bending $95.00 $135.00
Rust Bluing of Double Barrel Sets - (from) $225.00 $275.00
Back Bore and Polish (12 gauge & 16 gauge only) $125.00 $165.00
Regular (flush fitting) Choke Tube $17.00 $22.95
Sporting Clays Extended Tube (12 & 20ga.) $19.00 $24.95
Ported Choke Tubes (12 & 20ga.) NEW!! $39.00 $45.50
Steel, Card, Turkey, or 10ga Thin Wall $21.00 $27.50
Rifled Choke (Rem, Inv, & True) 12 or 20 ga. $39.00 $49.50
Return Shipping & Insurance (UPS Ground) $12.00

The above info is from Mike Orlen's site. Looks like good prices.

One thing you better find out first: are those barrels chrome-lined?

If so, your choices will be limited..

Good point Redneck! I own a Miroku SXS that was literally made for him while my uncle stood waiting for it at the factory. He was stationed in Japan at the time. Anyway that one doesn't have chrome barrels but that doesn't make it so for all.

So what would be the options with a chrome-lined bore? I have a Beretta Silver Snipe that has a imp cyl upper and a full lower with no selective trigger. I would like to open the lower to Imp cyl. I think the barrels are a little thin for tubes and without a selector I would rather have them choked the same.

i remember reading about loads developed to open up more than usual. No clue on the what or who.

Thanks to everybody for the info so far.

For now though, I'm hesitating on buying the gun. Just not sure if it's what I want to do.

I did find two local guys though that are both tooled up and able to open them up, if I change my mind on it.

I have had two of my shotguns opened up and thin walled choked and the only smiths i trusted to do this work was Briley. They aren't as expensive as most would think, but if they do charge a few extra dollars it is worth it, because you can bet the work will be done right.

"So what would be the options with a chrome-lined bore?"

There used to be a gunsmith that wrote for one of the magazines, I think his name was Baker.

He said that you had to have the plating removed. I don't know how this is done, or how expensive the set up would be for removing chrome.

I would go ahead and buy the gun. Miroku's are a great value for the money. Pattern it and shoot it a bit. You may well find the chokes to be not as tight as indicated. You can always have them opened up later if you want or you may decide to just use it as is.

Spreader wads can be had from several sources. I use the "X" wad inserts from Ballistic Products. They reliably open the pattern up by about one full degree of choke. That provides me with greater flexibility with fixed choke guns. Since I found myself not changing chokes very often in guns with choke tubes I've come to re-think the necessity of them and in fact almost prefer guns without them.

I had Mike Orlean open up an older SKB 28 gauge for me. Fantastic work, and if you are a member of shotgunworld.com it's $35 a barrel, plus $10-15 return shipping. Have never heard of anyone who has had anything but excellent results from him.

Interesting that you mention the "X" wad insert to spread the pattern. I used "Post" wads years ago to shoot the 16 yard line with a full choke trap gun.

Many competition trap shooters use high-end guns w/o tubes.. It eliminates potential problems..

Agreed.

But if I buy it, I'd plan on using it for a "general purpose" gun, mainly hunting and maybe some informal clays (no trap though).

I'm just concerned that Full/Full is going to be a bit tighter than I need, or want.

I'd open it up to about a nice middle-of-the-road I/C and Mod, and could be perfectly happy with that.

Still tossing it around....

That's the choking I go with for field shotguns. And, I shoot skeet with them too, informally. If Post wads are available for the chambering, I'd use them for the tight choke barrel at the skeet range. With the I/C barrel, it is so close to skeet bore, no need to spread the pattern. Lots of ways to skin the cat..