Please enlighten me. I have just purchased a new 30″ Remington trap barrel for my wife’s 1100. We shoot trap together, and her previous barrel came to an untimely end at the hands of a clumsy gunsmith. Other barrels that we had available were tried, but her scores dropped and her confidence faded. I wanted to give her a fresh start with a new target barrel, properly choked for loads developed for the distances we shoot.
You have frequently mentioned that choke tubes are mismarked, so I borrowed an internal dial caliper from work and measured the inside diameter of the barrel and the chokes. Here is the mystery. The barrel ID measures .740 until it approaches the choke tube. Within the last inch before the choke tube the barrel reduces to .729 . The three choke tubes that came with the barrel all start out at .740 and then constrict as follows: Trap Full constricts to .731, Trap Extra Full constricts to .711, and Trap Super Full constricts to .691 . I measured the barrel ID and chokes from an 11-87 30″ target barrel, and the dimensions were the same.
What are my constrictions, .009, .029, and .049? What does the .011 constriction in the barrel itself add to the equation? Is it some sort of pre-choke, or just a ton of protection against choke and barrel misalignment? If it is no magic “double choke” should I have it removed?
And lastly, would lengthening the forcing cone be worthwhile? My wife is a small person, and anything that reduces perceived recoil helps.
Thanks in advance. You have already helped us more than you could imagine.
Don’t worry. Your barrel is perfectly normal. What Remington did with the later 1100 and all 11-87 trap barrels was to try to combine the advertising benefits of “backboring” with their existing line of production chokes. Their existing chokes were cut for barrels based on an I.D. of .729″. They didn’t want to make an entire second set of choke sizes for the “backbored” guns, so they just left some permanent choke in the gun to take it from the backbored .740″ down to the .729″ that all their other barrels measured. They figured, correctly, that no trap shooter would ever want less than .011″, so they could get away with it by just relabeling the chokes and save some money.
While choke measurement alone doesn’t guarantee any particular pattern, it does give you a fair indication of what to expect. You should consider each choke to be the TOTAL constriction of the two (solid and screw chokes) starting at .740″. Looked at it this way you have .011″, .029″ and .049″ just as you said. This is more or less Improved Cylinder, Improved Modified and Xtra Full- sort of. It really depends on how they pattern.
I would skip lengthening the forcing cone on your 1100 barrel. I don’t think that you will be able to notice the very, very slight recoil reduction in a backbored gas gun. The best way to reduce recoil is to shoot the lightest load (both velocity and shot load) that will get the job done to your satisfaction.
Shotgun Report’s Technoid
(Often in error, never in doubt.)