I have two of Les' ( aka Thor Tamper) "curved" tampers and I could not tell you what mm the curve is.
Perhaps he will see this and respond; from the look it appear to be less then 2mm.
ginny
I love them by the way.

Hi Everybody!  I want to get another tamper and I want to try out a Reg
Barber and they have an option of getting on with an American Curve 1.661 MM
or a Euro Curve 3.355 MM.  Has anyone had any experience with both?  I want
to have a curved one because I feel as though it's a little easier to keep
the tamp level throughout the tamp than with a flat tamper.  Also I feel
that that since the side is raised a little the water is less likely to
force its way through there.  David Schomer talked a bit about that in his
book but unfortunately nothing about the curvature of his tamper.  ...
Thanks for your input! -Gary

Haven't compared the Reg American curve to Euro curve but during PNWGIII we 
noticed Greg's Click tamper was much more curved than my Reg American. He 
was having constant shot problems until switching to a different tamper. 
YMMV.
miKe mcKoffee
URL to Rosto mods, FrankenFormer, some recipes etc:http://mdmint.home.comcast.net/coffee/Rosto_mod.htmUltimately the quest for Koffee Nirvana is a solitary path traveled by many. 
To know I must first not know. And in knowing know I know not. Each Personal 
enlightenment found exploring the many divergent foot steps of Those who 
have gone before.
From: "Gary Theisen Jr" 
Sent: Tuesday, June 28, 2005 3:22 PM
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Ginny,
I am such a nice guy, I will answer! My standard is 1.5mm. I have done the=
 
European profile, but I think it is too much of a curve. Personally, I use =
a 
1.5. I have been make a lot with just 1mm. Shomer's tamper is very close to=
 
1mm. The way I finish my tampers, they have a soft edge, and I think that a=
 
flat tamper works just as good as a curved. It is a matter of preference.=
 
Through testing, I have found tamping will not correct a bad doseing job.=
 
You must have a nice level evenly distributed dose.
 Les
 On 6/29/05, ginny  wrote: 
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