Chokes and Patterns

Hi Bruce,

I have a Browning 725 O/U sporting ,12 ga.,with Invector DS chokes. I’ve been shooting sporting clays for almost a year now.Been reading all the stuff on different loads ,and chokes so I did some testing and what I found surprised me. I tested quality target loads,Challenger #8, Rem.Gun Club #8 and WAA #7.5 Tracker all 1 1/8 oz. I tested Mod. I.Mod. and Full chokes,four shots each at 40 yards and 30″circle .The best was the Challenger at 60%,WAA at 55% with Full choke,and I did count all the pellets in each shell so I think it,s accurate. I even measured a 27″ circle still same percentage.What I’ve read is doesn’t matter whats stamped on the choke it’how it patterns. So my question is should I be looking at getting a Ex.full choke or living with what I’ve got. Really enjoy reading all your stuff,keepup the good work ,thanks, Phil


I’m not familiar with the Challenger or AA Tracker shells. The former are Canadian-made and the latter are designed with a special wad to permit (in theory) observance of pattern placement in the air. I have no idea of the patterning qualities of these shells.

I am familiar with Remington Gun Club shells. They have softer shot than the STS, so will pattern 5% or or even a little more open in my experience. I’d be interested in seeing what your chokes do with STS shells or the better quality Federal target loads. Remember, the shell has as much to do with the density of the pattern as does the choke.

60% is the benchmark Modified pattern for 40 yards and a 30″ circle. 65% for ImpMod, 70% for Full.

In 12 gauge a typical Mod choke has about .020″ constriction. ImpMod is around .025″ to .030″ and Full is often .035″. But recent Browning chokes have tended measure more open than usual. When I reviewed the 725 Sporting for my column in Shooting Sportsman Magazine, my sample gun had a .740″ overbore barrel bore. But the surprising thing was the choke dimensions: “Five chokes are included with the 725 Sporting. With their constrictions, they are: Skeet, minus .003”; Improved Cylinder, .002”; Modified, .006”; Improved Modified, .014” and Full, .039”. With the exception of the Full, these are extremely open constrictions for their designations.”

An ImpMod choke that measures like a Light Mod can’t be expected to hold a tight pattern. That said, the Full choke of .039″ constriction is certainly up to snuff and should perform normally. Also remember that choke constriction and shell quality may be the major influences on pattern density, but forcing cones, barrel bores, gap where the choke seats to the barrel and some other small things also influence patterns.

Bottom line: Try using higher quality shells to see how much that helps. And do remember, in sporting clays a true Modified pattern of 60% should be able to deal with just about anything. Andy Duffy once told he that he won one of his National Championships with a Light Mod choke that he never changed during the event.

Best regards,
Bruce Buck
Shotgun Report’s Technoid

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