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Shotgun Barrel Alterations for Steel Shot

Informative Article No.5

A guide. (17/12/02).

In the very near future wildfowl hunters will be asking the question “Is my gun suitable for steel shot?”.
In most cases the answer will be, “Yes, but with some alterations to the choke and forcing cone areas, and as long as you will only use 2″ 32gram ( 1 1/8oz) standard (non-magnum) steel factory loads.” (Actually soft-iron shot).
The answer will be “No”, if it is an exceptionally poor quality gun with low grade steel and finishing, or if there is already excessive wear or “play” in the action. In most cases guns chambered for 2″ are not safe to lengthen to 3″ chamber, but there may be some exceptions. For most duck shooting situations over decoys, 2″ shells will be perfectly adequate anyway, with a practical target range limit of 35 to 40 yards, using shot size #4, #3, or #2. The days of “sky busting” are over!!

We are now equipped to alter the fixed chokes and forcing cones on all 12ga shotguns, including those with chrome-plated bores. The tooling is piloted by the bore, so chokes are guaranteed to be perfectly in line and concentric (not bell-mouthed, as some hand-turned reamers are prone to do.) The altered sections are then carefully polished to remove the machining marks to a smooth finish.
The forcing cones ahead of the chamber are also reamed to a more gradual taper to minimise “shot mashing” and to keep chamber pressure down, thus reducing recoil effect as well. This work does not significantly alter shot velocity.
(Note: Chrome lined bores are not re-plated after alteration, so they must be cleaned and maintained as would a non-plated bore. The chrome plating will not strip provided it was originally done to a high standard, and as long as the barrel is well maintained.)

The firing of steel shot through a barrel with a choke restriction too tight may result in a ring-bulge at the choke section. Excessive chamber pressure will wear a guns action prematurely. It is a better investment to attend to these matters now if you intend using steel shot rather than to take the risk and have to deal with “complications” later.

Price guide (Based on time taken to complete each job, individual guns may vary. Any additional work required is at $30.00/hr +GST, and parts.):

  • Double guns – about $200.00 Incl. GST to alter fixed chokes and forcing cones.
  • Single barrel guns – about $140.00 Incl. GST to alter fixed choke and forcing cone.

Screw-in choke installation may be an option for some single barrel guns if desired. Forcing cone alterations only may be required for guns already fitted with “multi-chokes”. Special choke tubes for use with steel shot are available for a lot of common shotguns, so enquire with us if you require any of these.

Preliminary patterning tests with factory loaded 2″ #4 steel shot loads carried out recently, found constrictions of 0.005″ (skeet) and 0.010″ (improved cylinder/ choke) to be ideal at 35 to 40 yards. Tighter constrictions up to “Modified” (0.018″) actually showed a decrease in pattern percentage.
These tests however were not exhaustive and will be revisited in the near future.

If you have any queries please contact me.

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