Bruce,

Hi-I haven’t conversed with you lately and believe me, my shooting and my enjoyment of it have suffered for the lack of intelligent contact.

My question is for choke tubes in a trap gun. The gun in question is a reborn Model 12 Win. Everybody in my club has discarded this standby for newer, sexier tools so what do I do but drag the old girl out again so I can try whip their butts with her.

The particular gun I want to use is 30″ Full choke (.690) at the muzzle with a bore of .730. I want to get a set of choke tubes (3) for all yardage and wanted your advice on makers and proper constrictions.

By the way, I will not have any forcing cone lengthening, backboring or porting done. I consider these fine things to do to enhance the economic picture of your gunsmith but of little real value to me, the shooter.

Your point of view will certainly be appreciated.

Thank you for your consideration,

Mark

Dear Mark,

If it were my gun, I would probably shoot it just as it is and not install screw chokes. Most of the trap pros use full choke at 16 yards. You don’t mention what your handicap yardage is, but anything from 24 back is strictly all the choke you own territory. Most people break their birds about 16 yards out of the house, so you add your yardage to that.

Warren Johnson generated an interesting pattern program he called SPRED. From this he designed his “Choke Chooser” slide card. Warren writes for Shotgun Report and we have gotten to know each other over the past couple of years. He is a math Ph.D. and really knows his stuff.

Using the patterns generated by Choke Chooser, it lists 35 yard patterns on “trap view” targets (1/4 turned) as being maximized at 18″ when using 1 oz #7-1/2s and 19″ using one oz #8s. In each case the most effective choke to obtain this pattern is Extra Full. Full would be the best choice at 30 yards for #7-1/2 one ounce loads, while Imp Mod would be best at 30 for #8s one ounce.

In 1-1/8 oz loads at 35 yards (the distance at which a slow, but not extremely slow, 16 hard shooter takes his birds), #7-1/2s still require Extra Full to achieve a maximum 19″ pattern, while #8s need Full to optimize their most effective pattern at 21″. Warren uses an 85% chance of a two pellet strike to set his pattern parameters, which I think is pretty fair. Note that the extra 1/8 oz of shot actually increases the killing size of your pattern. It doesn’t just put more pellets into the center. If you think about it, it makes sense.

So- if you believe in computer pattern calculations (based on a ton of real world data), you would use Full or Extra Full from the 16 yard line if you break your birds around 17-18 yards out of the trap. Or, you can look at what the pros use- which is also Full for 16 yard birds. Either way the answer is the same AND you save $150. If it helps, I use .035″ (Full) and 1-1/8 oz #8s for 16 yard and the same choke with #7-1/2s for handicap and wobble trap.

One other thing to remember- many people do not believe that the screw chokes produce as good patterns as the solid chokes. Pigeon shooters and most long handicap trap pros stick with solid chokes. They do this because they believe solid chokes throw better patterns. Whether you believe this or not, it is a fact that it is not as easy to regulate the proper length of the cone and parallel sections on screw chokes because all the chokes are the same length. In a perfect world, the more open the choke, the shorter it can be. The tighter the choke, the longer the cone and parallel sections are. The screw choke world is not a perfect one in that respect.

Another disadvantage that the screw chokes have is the relief at the rear of the skirt. This is a little “jug” choke in effect and, what ever its other effects, is a bump in the road the shot must travel. Bumps are never good. Some makers have a rather large step at the skirt. Others are better. Nigel Teague, the ex-Rolls Royce machinist who does ultra high end screw choking in England, hand fits his chokes to the bore and there is virtually no jug effect. However, he still can’t overcome the fact that his full choke tubes can’t be as long as they should be.

Screw choke tubes sound good and for many shooters they are, but there is a price to be paid- as in everything.

For what it is worth, while I don’t believe in backboring or porting, I do think that lengthening forcing cones helps prevent a small amount of pellet distortion and also reduces perceived recoil slightly. If it were my Model 12, I would probably lengthen the forcing cone and keep the chokes as they are.

Best regards,

Bruce Buck
Shotgun Report’s Technoid
(Often in error, never in doubt.)