ASSRA Forum - Width of Flats for Various Barrel Contours

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Width of Flats for Various Barrel Contours (Read 1887 times)

S99VG Oldtimer Offline Posts: 514 Location: CA Joined: Feb 1^st, 2020	Width of Flats for Various Barrel Contours Apr 17^th, 2021 at 6:04pm	Print Post
	Can anyone point me to a chart or table that gives the width of flats for octagon barrels. If not that, then can someone tell me what the width of the flats are on # 2 1/2 and #3 contour barrels? Thanks


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buchsenmacher Full Member Offline Posts: 209 Location: Adrian, MI Joined: Apr 18^th, 2004	Re: Width of Flats for Various Barrel Contours Reply #1 - Apr 17^th, 2021 at 6:24pm	Print Post
	On an octagon the width of the flat is .414 x diameter across flats. example: barrel 1.050" across flats, 1.050 x .414 = .4347 flat width.

	Steven Durren Professional member, ACGG
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JSB30 Senior Forum Member Offline Posts: 407 Location: Missouri Joined: Apr 30^th, 2011	Re: Width of Flats for Various Barrel Contours Reply #2 - Apr 17^th, 2021 at 6:30pm	Print Post
	Per Robert J Snapp To find the dimension across corners multiply the distance across the flats by `1`.0824. To find the width of flats multiply the corner dia by .3825 or multiply the flat dia by .414. #3 at breech 1.05 flat dia, 1.137 corner dia, .435 flat width. #3 at muzzle .95 dia flat, 1.028 corner dia, .393 flat width. #2 1/2 ? Barrel dimensions were not always perfect.


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JSB30 Senior Forum Member Offline Posts: 407 Location: Missouri Joined: Apr 30^th, 2011	Re: Width of Flats for Various Barrel Contours Reply #3 - Apr 17^th, 2021 at 6:42pm	Print Post
	See if you can make heads or tails out of this


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JSB30 Senior Forum Member Offline Posts: 407 Location: Missouri Joined: Apr 30^th, 2011	Re: Width of Flats for Various Barrel Contours Reply #4 - Apr 17^th, 2021 at 6:43pm	Print Post
	WOOPS


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S99VG Oldtimer Offline Posts: 514 Location: CA Joined: Feb 1^st, 2020	Re: Width of Flats for Various Barrel Contours Reply #5 - Apr 17^th, 2021 at 9:49pm	Print Post
	Actually I'd like to know the barrel contour number for a barrel with a 15/16ths wide flat. I'm using the barrel chart on the CPA web site for contour numbers - hence the #2 1/2 contour. I don't have a barrel in hand to make the calculations but I do have a forearm with that width and I'm trying to match it to a contour. Thanks


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Sure shot Frequent Elocutionist Offline Posts: 1169 Location: East central Iowa Joined: Jun 22^nd, 2020	Re: Width of Flats for Various Barrel Contours Reply #6 - Apr 17^th, 2021 at 10:13pm	Print Post
	Don’t you mean across the flats or diameter of barrel? A .875 or 7/8” across the flats is a #1, and a 1.00” is a #2 according to CPA’s website. So a .9375 or 15/16” would be a #1 1/2 I guess.


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S99VG Oldtimer Offline Posts: 514 Location: CA Joined: Feb 1^st, 2020	Re: Width of Flats for Various Barrel Contours Reply #7 - Apr 18^th, 2021 at 12:13am	Print Post
	You sir are absolutely right and I don't know where I got that stupid idea in my head. My apologies to all, I have seen the error of my question and yes I do mean diameter. Geez, maybe now some of the answers might start making sense. Thanks!


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