doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com 20g bore diameter

Gunman;
I believe you have your decimal point one place off. 1 mm = .03937" (1/25.4) or approximately .040". Thus .1 mm = .004" while .01 mm = .0004" or a bit less than � thousandths.
I was thinking the sizes were only stamped to one decimal place but wasn't absolutely certain so didn't say it that way.
In machine shop lingo, although not perhaps technically correct .1 was called 100 thousandths, .01 10 thousandths, .001 one thousandth &.0001 one tenth, which meant it was a tenth of a thousandth. This was universal among all machinists I ever knew & many of them came from widely different locations.

Hallowell is the only one that uses a spread like .005 to .011???? The only thing I can figure is they are talking about an IC choke giving an IC size pattern at a given yardage. I know I have been surprised when patterning guns giving much smaller or larger patterns than they should have, given the restriction. I am convinced how the choke is configured has a lot to do with the size pattern it may give.

The Cam 70 means it has a 70 mm (2 34") chamber, don't recall the HE offhand.

Piper you are correct and sorry for the confusion . This modern metric is not my favourite. It was always claimed the British gun trade worked in "attles" to wit attle do and attle be near enough .

Not to split hairs but, one (1) mm=.3934 inches, not .3937 inches. Obviously I AM splitting hairs!! Sorry.

So now a mm is well over a quarter of an inch long? And where did you get the "hair" to split?

Well not to split hairs "BUT" 1 cm =.3937". 1 mm =.03937". Rounding mm's to four decimal places will give .0394". My convert program shows 1 mm carried to 8 decimal places as .03936996. Rounding to 5 places gives us .03937, not .03934.

Here is my original statement on this, as you can see I did use mm's not cm's which was actually the error I was correcting & to which you have followed suit;

Those guys who talked about the number of angels that could dance on the head of a pin have nothing to us with our hair-splitting!

Not positive, but I believe the HE 1.2 might be the barrel weight in kg.

1.2 kg would convert to around 2 lb 10 oz. This would certainly be a feasible weight for a light set of barrels. I was just not sure what the HE stood for so was hesitant to state this was bbl weight, but you're probably right Larry.