Utilizing a fixed cylinder bore barrel to it’s greatest potential

[Tall]

Cylinder bore and Improved Cylinder bore are frequently used to improve the pattern when using #9 shot for skeet shooting. I think if shooting #4 shot at a steel target you would want to have a full choke or at least some choke.

[Kennibear]

I have a $15 "Long Range Winner" sold in the 30's with a Genuine Nickle Steel barrel that I cut from 30" to 18 1/8" so is obviously a true cylinder bore barrel. With 1 1/2 Oz of #5 lead shot and a moderate load of Unique that is subsonic it patterns very well and very even to about 35 yards. With that much shot it fills the ideal 30" circle fully and evenly and definitely improved my hits on Chukar Partridge as it was very fast to mount. Two rules to follow: 1) Paper doesn't lie. Pattern every load through your gun. 2) Subsonic loads perform better than you think.

KB

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[725]

It's an old technique, but some have had success by "jug choking" a cylinder bore. I'd find a credible source for actual descriptions on how to do it, but as I understand it, using a cylinder hone, you enlarge the bore a few inches away from the muzzle. Cheap & easy way to tighten the pattern. As above, if the wall thickness is sufficient, screw in chokes will answer your needs very well.

[HWooldridge]

Bob Brister describes jug chokes in one of his books, and shows basic dimensions.

[Barry54]

As Long Bow said, "you need Rifle Sights " on it. But to really get it to perform you need to send the Barrel to Vang Comp. They can also install the Rifle Sights.

The Vang Comp process consists of Lengthening the Forcing Cone to 3" long from it 1/2-3/4 current length. Then the Back Bore the Barrel to .745 until the last 2" which taper back down to .730. Then they port the barrel with 62ea. 1/16" holes on either side of the Front Sight starting back 2" from the muzzle.

The end result will make your gun pattern 00 Buckshot (9 Pellets) into 7" at 25 yards. It will also shoot slugs or round balls well and your Birdshot will do the same thing, but spread out faster past 25 yards..

A Stock Cylinder Bore Barrel will pattern 00 Buck into 15" at 15 yards and add 1" to the pattern for every yard beyond that. and that is what you are dealing with right now.

This process is considered the "Ne Plus Ultra" for Police Shotguns in this country for the last 40 years! And this company has done literally Thousands of Barrels for Police Agencies, the Military and even DHS.

This outfit is always busy and sometimes their lead times are long, but if you only send your barrel it can be turned around in 2-4 weeks.

www.vangcomp.com

Hope this helps? Also see this thread. https://www.calguns.net/calgunforum/....php?t=1651983

Randy

So what is the advantage of the Vang Comp process of lengthening the forcing cone and backboring over having the barrel machined for screw in chokes? Seems like screw in chokes would be more versatile??
Is the VangComp process equivalent to say a modified choke? Or?

[Kennibear]

Vang Comp can be done on a barrel too thin for a screw in choke. Large selection of chokes is always a good thing. I have a Poly-Choke on an old pre-1100 Rem and a quick twist changes everything. Not for everyone.

KB

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[Mk42gunner]

1980's Remington 12 pellet 2 3/4" 00 buckshot patterned very well from a cut down 23" barrel on a Mossberg Model 600.

Shot all the shells and the gun was traded a long time ago.

Robert

[W.R.Buchanan]

So what is the advantage of the Vang Comp process of lengthening the forcing cone and backboring over having the barrel machined for screw in chokes? Seems like screw in chokes would be more versatile??
Is the VangComp process equivalent to say a modified choke? Or?

Barry: I explained what the Vang Comp Process is in post #14.

Lengthening the Forcing Cone spreads the 'Recoil Impulse' out over a longer period of time Reducing "Perceived Recoil." The "Porting also helps in that regard as the Gas Pressure is reduced before the Payload goes thru the Choked area of the barrel so in effect it is coasting thru the Choke so there is less shot deformation.. The "Back Bored" portion also reduces the friction on the payload as it goes down the barrel which increases velocity somewhat.

The end result is a gun that will shoot 9 pellets of 00 Buckshot into 7" at 25 yards. And "Cylinder Bore Barrel" will only do 15" at 15 yards, and at 25 yards the pattern will be 25" which will result in some pellets off the target ,And since you are liable for everyone you send downrange this can cause Legal Problems you don't want.!

This was all concocted by Hans Vang when he was a high end Shotguns Smith is Santa Barbara CA. He was working with Expensive Trap guns which at the time didn't' have interchangeable Choke Tubes. He was trying to get these guns to pattern inside the normal 30" circle at 50-60 yards on the Trap Field. and the barrel mods described, worked.

Then the Santa Barbara Police came to him and asked if that procedure would work on their Rem 870 Police Cruiser Guns,,, and it did!,,, and it does! As evidenced by my two M500's which have it done.

Teh group at 15 yards is under 3"x3" and the one at 20 yards is 2"x5".

A Modified Choke Tube won't duplicate this.

I hope this answers your question

Randy

[Barry54]

Randy, thank you for both of your replies. I called VangComp last Wednesday, Thursday, and Friday. Someone finally answered Friday when I called on my lunch break. I was told that the porting caused approximately a 3% velocity loss and roughly One decibel increase from the shooters perspective. (After I said I was reluctant to get porting due to an increase in noise) I was also told that the process roughly equates to a modified choke. I was also told that if I was just going to shoot birdshot I’d be well served with having it fitted with interchangeable chokes.

I’ve ordered a heap of components and will work up some test loads as time permits. I’m interested in their process but not in a huge hurry or need to have it altered.

[Barry54]

I also read on their website that they don’t guarantee the pattern Results with their process performed on a barrel with interchangeable chokes. Or something to that effect, however it was stated.

I was unaware of their process and researched back boring and forcing cone lengthening after you suggested them. I heard proprietary a couple of times during my phone conversation with them. JD Jones made the 300 Whisper proprietary and someone changed the dimensions 0.015” in the throat. They called it 300 black out and dominated the market afterwards.

I’ve got a lot to learn and research is cheap!
BPI $1.99 subsonic brochure is on the way.

Found Marty’s molds while I was on the BPI site. I’m intrigued with his design vs the Lee 18 cavity buckshot mold. The reviews lead me to believe the Lee 18 cavity is problematic with the smaller buckshot sizes. I experienced some of the complaints with the largest version of the Lee 18 cavity and can see how it could be worse with smaller sizes.

And I think I may have the components to assemble some buffered loads after three orders back to back. I’ve got another shotgun with interchangeable chokes and plenty of butcher paper and corrugated boxes for pattern testing.

Picked up Hodgdon’s free “2023” reloading pamphlet and it still has loads for the Federal 12S4 wads in it...
How long have they been discontinued? Why isn’t someone making a replacement for them?

[M-Tecs]

I was unaware of their process and researched back boring and forcing cone lengthening after you suggested them. I heard proprietary a couple of times during my phone conversation with them.

My dad had Stan Baker lengthen the forcing cone and backbore his model 12 trapgun in 1975. It was not a new process then. A.H. Fox was doing it in the 1920's and possibly sooner.

https://www.gun-tests.com/accessorie...otgun-barrels/
This is no new practice. British gunmakers started using this technique in the late 19th century. Back then they called it freeing (not to be confused with free-boring), but this practice soon lost favor in light of the development and refinement of the fixed choke.

Early in the 20th century this trend resurfaced. The A.H. Fox Company in Philadelphia had a shotgun-bore mechanic named Burt Becker. His experimentation with back-boring produced some of the best long-range waterfowl shotguns of their time. These were the Super Foxes and HE-grade shotguns, and their bores were as much as .014 inch oversized.

[Barry54]

This article explained a lot to me on what the process did/does. They also mentioned testing with cheap buckshot instead of ultra premium tactical buckshot loads designed for tactical shotguns with improved cylinder or no choke constricton. So there’s hope that I can make improvements by ammunition changes mentioned previously by others who answered my questions here.

https://rifleshooter.com/2012/07/tac...e-performance/

[W.R.Buchanan]

My Browning Citori CXS that I bought last year came from the factory Back Bored to .740 with the Forcing Cone extended and interchangeable chokes as well. I run Cylinder Bore Chokes for Skeet but with the back boring they pattern like IC chokes because it is total amount of constriction that matters. IE .740 to .730= .010 constriction which would be IC. just like .730 to.720 = .010 constriction, which is normal IC.

The reason why they don't guarantee the exact pattern any more is because they can't control which ammo you will use in the gun. All of the regular Low Recoil Ammo will give you the results shown above.

The problem with trying to duplicate Flight Control ammo is the Wads. Nobody but Federal makes them and they are patented so they aren't available anywhere else and Federal doesn't sell them as components.

One of my shotguns, the "Monkey Berg" (Monkey Wards M500) has the barrel done with the forcing cone and choke tubes. I cut off a 28" Vent Rib barrel to make it. I didn't want to alter the diameter of the bore because the gun was going to be used with a Rifled Choke Tube and my Cheap Lee Slug Loads. Accuracy has been excellent with that combo. On the target below there is 4 slugs thru the big hole on the left. I then made a windage correction and the 5th shot was on the centerline of the target same elevation..

Randy

[Barry54]

Got the $1.99 subsonic loading pamphlet from BPI and it only has five 1oz loads on the back of the sheet of paper. That’s the light load on the left.
The center load is 1-5/8 ounce of #5 and the right one is the same volume of #2 shot.

Now I just need to get time to pattern test them...

[W.R.Buchanan]

Barry: Thanks for putting up that Article !!! I think I may buy the reamers ???!!!

I already have the Flex Hones and Tap Handle and can make the Extension.

Randy