Measuring Choke tube constriction

[crabo]

What is the best way to measure choke tube constriction? I shoot a Browning Citori GTI. I bought a set of Briley X2 extended light mod choke tubes. I can hit way better at trap at the 27 yard line than I could at the 16 with the Browning factory modified choke tube.

I have ordered modified and full from Briley to further test them out.

Would an inside mic be the best to find out how the factory constrictions compare to the Brileys? The Briley X2 extended chokes are the same length as the factory GTI chokes.

I guess I need to get on the pattern board and do some testing also.

[geargnasher]

Brownells's sells an excellent choke gauge, but it's a bit spendy for one or two uses.

Just measuring the muzzle with an inside mic will tell you the size, same as the markings on it will, but not the contour. Good choice on the Brileys by the way.

Gear

[runfiverun]

there is a tool for measuring bbl's and chokes some gun shops will have them.
how choke is measured is by the amount of constriction in the choke in thousandths.
but it doesn't take into account the overbore of the bbl or the draft angle of the choke itself.
i used to have the numbers memorized as to how much constriction was deemed what choke.
it seems it went from none cyl bore to something like .0030 for full choke and 20 modified and 10 for imp cylinder.
but chokes have improved so much it seems they have 35 different constrictions now.
but knowing your bbl's internal diameter will allow you to make a better choice as they are not all the same.
the older 12 ga bbl's were sposed to be 729 now they are more like 740 on average and some are 775 [10 ga]

[crabo]

I was wanting to compare Briley's vs Browning. Not something I am going to spend much money on.

I have all Briley's for my Benelli, but I hate having to buy two of most of them for the the O/U.

[runfiverun]

most o/u's shoot a different choke in each bbl.
something like imp cyl/light mod.
or mod/full.
this gives you a close- far shot selection.
they are similar in constriction but gives you about 5-6 yds distance for your pattern coverage. like a 60% center fill at 30 and 35 yds.

[geargnasher]

A phone call to Briley with a description of what you have, and what you want to do at different ranges would clear all that up in short order.

Tell them exactly what you intend to do with the Browning, what loads you will be shooting, and they will tell you what you need. Most of this is based on a 30" pattern. The choke rating is the distance at which it will create that pattern size. If you shoot skeet with lead #8s, you likely need a skeet or modified. Trap or bunker is a different story.

Gear

[fecmech]

I've done over 500 patterns on a pattern plate at my home comparing various chokes etc. The bulk of my work was with Briley and Beretta factory chokes. The ONLY advantage that I could see between the two was that I could change the Brileys with my fingers due to the extended portion. That was it. Pattern density and quality was equal between the two. I did a fair amount of pattern work with 2 Browning 20 ga guns, about 100 patterns and results were the same there. One thing interesting with the 20's was that the one barrel was .005" bigger than the other and patterns with the same choke were almost always close to one step tighter than what the choke was marked. Your degree of choke depends on the difference between the choke constriction and barrel bore diameter. The MOST important factor in good patterns is shot quality, period. The best shot "quality" is in factory target loads ie. STS, AA handicap, Federal Gold metal. I have not seen any bagged shot as uniform as what is found in good factory target loads. I don't think there are any serious State or National level Handicap shooters using reloads in competition.
When you do your patterning, do at least 5 patterns for each load to check your percentages. One pattern doesn't mean much and you can "over choke". My Beretta did better at long range with the "modified" constriction than it did with "full". I had nice even 85% patterns with the mod at 40 yds while the full would run closer to 80% and patchy. That was with either Beretta Mobil chokes or Briley. If you have access to a pattern plate it sure makes life easier. I used a 4' x 4' steel plate covered with white lithium grease. Shoot the pattern, draw the 30" circle and count the pellets and then "paint" the grease with a brush and repeat. Good luck.