doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Skeets Bore Gauge - Accurate?

Aaahh, what's up(Rev)Doc? Mensuration is a perfectly good word for methods of measurement altho perhaps not of the linear King's hand/foot/digit sort; more having to do with formulae for determining volume of solids and such. Only the devotees of chock tubs mistake it for the-um-"curse". For a moment there, I had the thought that it might just be that time of month for a noted ex-spook but no, that can't be, can it? More likely missing the acute reading comprehension skills of us-uh-rabbits. And thanks for "tagging up" Mike. Lot of that going on. I hate it when they hold hands and jump from the ropes! Gotta go; think that old sci-fi classic "Night of the Lepus" is on fx right now.

jack

Mike, I think we all got that. But where Jack fell off the wagon was with the brass drop-in gauge--because everything it tells you is based on the assumption that the tool itself knows the bore diameter. Which it does, but only IF the bore diameter is standard. Which is a big IF.

Rabbit wrote and Rabbit quotes: "I should add that there are a host of pretty savvy guys out there who think one of those brass shoulder gauges tells all honestly. Avoiding actual measurements by the method mentioned sometimes rings a little bell for them and they get beyond the "nominal" constriction and the gauge standard bore. Mensuration is also useful for determining other info about the old sewer pipe."


For cat's sake, Larry, you're putting me in a Brown study. Please read this excerpt from my earlier post and THEN tell me that I am advocating use of a "ring sizer". I thought I was providing the antidote for the common misconception that it "tells all honestly."

jack

Jack, I think it's a clarity issue. Failure to communicate, if you will. First, we have the savvy guys. Then we have that avoiding actual measurements rings a little bell for them etc. I read that as a POSITIVE comment about the drop-in gauge, not negative. In my business, guess I've gotten used to making things clear to readers. Or, if I don't, some editor beats me over the head about it. (Deservedly so.) The way you worded your quote, there's no way I can tell that you're "dissing" the drop-in gauge.

Just for informational purposes, I was at a gun show two weekends ago, was looking at a shotgun in the ten thousand dollar range. On measuring the bore, I found that is was .070, yes, seventy thousandths, larger than nominal bore size. Now tell me that I shouldn't zero on a ring gauge before measuring constriction. What good is .030 of constriction on a ten thousand dollar gun if it's been hogged out by seventy thousandths?

Larry,
Maybe it's me but I understood perfectly well what Rabbit was saying.The brass choke gauges are only any good and then only as guidance if your bore is 0.729" for a 12.
In case there is any more confusion to be cleared up, a brass gauge calibrated to suit 0.729" is not any good for overbored 12,s or standard bore 20's.
Just in case it is not clear.
Finally being sensical, you need to measure a barrel with a bore gauge such as a Chubb dial gauge. But no matter what the constriction is at the muzzle, that is NOT the choke.It is the constriction.
Choke is the percentage of pellets of the complete number of pellets loaded into the cartridge that are within a 30" diameter circle drawn around the main mass that have hit a pattern board or pattern plate when shot at a distance of 40 yards from the plate.
Measured constriction of choke will only give an approximate idea of what pattern to expect. This can be greatly influenced by various cartridges and the construction of cartridges with regard to powder, wad, shot etc.

I also understood was Jack was stating.

"Measured constriction of choke will only give an approximate idea of what pattern to expect. This can be greatly influenced by various cartridges and the construction of cartridges with regard to powder, wad, shot etc."

I am glad that you put that in, as too many people judge what is stamped on the barrels or what they read on a gage. I have seen it more than once on this site, where someone bought a gun on an Internet auction and without having the gun in hand want to send the gun to someone to have the chokes opened because of readings given or what is stamped on the barrels.

Your last sentence sums it up.

Larry, I understand how you could shade the argument toward the view that really getting down and dirty with the mils would ALSO ring a bell for these guys but you do have to remember that many of us don't spend weeks and years with a caliper or mic in our pocket. There are very savvy people on this board who are "innumerate" when it comes to getting the decimal point in the right pew. So, yes, I agree with you and Bill that it is better to know the diameter of the bore and the minimum diameter of the choke and I agree with David that patterning with your load of choice tells the final tale and I agree with Bill that a big backbore and the original choking could produce, in Bill's case in hand, a constriction of say .11". I agree to agree and I agree to not be quite so vernacular and shorthand in future. I understand that I'm being held to a high standard of commo and I take that as a sign that there's some hope for me.

jack

+/- .001" accuracy.

Works great.