doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Measuring .410 choke

A number, .0??". I just want to know exactly how many points of constriction I have in my guns. I want to be able to measure the choke in a potential purchase, and I want to be able to describe it accurately if I decide to sell. I have already patterned the guns, and know what they throw. I like to know what I've got in the gun, then I can see by patterning if it the patterns are consistent with the constriction.

I have patterned many guns in my life ........ on plates, on paper, on the side of abandoned cinder block buildings, even on the doors of junked cars. I like a grease plate the best. I used to think it important to save the patterns, so I used paper. No more. If it's important enough to save I snap a digital pic of it. I have also chronographed many loads. One interesting thing is how close the velocity always was to published load data, and to the velocity printed on the box of factory loads.

SRH

That's for sure. There are as many measured velocity contradictions (vs factory specs) as you will see with actual constrictions vs what's stamped on the barrel. 3" .410 shells are exhibit A - all over the place.

You can't have too much data. The old line of "patterns are all that matter" falls short when buying and selling. If there is little choke, and the gun throws a tight pattern with someone else's pet skeet load, it may or may not be acceptably tight for a hunting load.

CHOKE MATTERS.

I can work with metal that is there. If it isn't there, you are limited in what can be done to tighten patterns. How many of you would buy a gun for pass shooting geese that wasn't tightly choked, but the owner said "my pet load is incredible in this gun for geese at great distances"?

Like Stan, I want to know what I have and what I'm buying.

The line about patterning and not worrying about choke has been parroted so many times, people have lost touch with reality. There actually is a direct correlation between choke and pattern with a given load.

Well said, Chuck. Thank you.

SRH

You are very right about needing to know what constriction a gun has. A lot of guns have had choke work, both good and bad, done to them over the years. I had to have a few gun back bored behind the chokes to try to get some choke back into a gun someone else reamed out.

Saddest case was a mint condition high grade Smith 32" barrels, 3" chambers some previous owner had opened to cylinder and cylinder to shoot steel shot in. It went from a great waterfowl to a collector closet queen. The patterns were just awful. I sent it down the road. Not enough metal for thin walls, not enough metal to back bore a little choke into it. And when I start thinking about thin walls in a high grade double I am desperate. Had I know how and had the tools to measure it I never would have bought it in the first place. From that one gun I learned how and why I need to measure things better

I have the CSP set for 5 gauges - 12 through .410. I have found several .410s that were choked so tight I could not get the bore gauge in them. I measure the bore from the chamber end in as far as I can, about 17", and then ASSUME that the bore diameter is the same all the way to the choke. Then I measure the diameter of the choke with a dial caliper. This does not allow me to measure the length of the choke or its profile. Not perfect, but close. These barrels that the gauge would not fit in all had over 0.020" of choke when measured indirectly as above and threw very tight patterns with small shot (8s and 9s). Not so good with #6 shot.
Regards,
Jeff

Chuck,
With all due respect, He isn't buying. He isn't selling. I'm going to guess he isn't pass shooting at geese, because, he said he wanted to measure constriction on a .410, but, I guess you never know. You can measure all you want, but, the direct correlation between choke, pattern, and given loads gets fuzzy in a .410. If anyone is parroting anything, it is the guys with a spiffy new micrometer, who measure a gun and declare it to be such and such choke, and head out with a variety of ammunition they have never, ever patterned said gun with said loads.

Choke matters, when you have done the homework. If you haven't patterned, you haven't even started.


Best,
Ted

I am most definitely not one of the technical guys here, but Ted's take on this problem rings true with me...Geo

Ted, no disrespect and none taken. Patterning IS important too. Choke is the equipment to facilitate the desired pattern. Sometimes more or less choke for the load at hand to get desired results. Some loads just don't pattern well, etc..

But if we know the internal configuration and dimensions of a barrel, Most of us have a good idea of its performance with loads we have experience with. We can buy a P-gun with a skeet choke and toss in some AA skeet loads and we are not likely to be surprised.

Do telescoping gages have radiused ends so that they will give a true reading of the inside diameter of a bore?

SRH