Believe what you want . What else would they be ?

Mark, I think you took my last reply the wrong way. What I was trying to say was Cheddite makes two different size primers, a European size, and a American size primer. I have measured Cheddite 209 primers and they are the same size as Win primers. I know I can go from Win to Cheddite and back without any problems with fit. On other reloading web sites guys have said about problems with fit if they get the wrong Cheddite primers. I know RIO primers are bigger. Hope this clears things up a bit.

I have never heard they made 2 different sizes before . I know they make different strength primers . But the only ones I have seen available here are the Clerinox CX2000 type 209 . Which are the ones I use that in Cheddite hulls that stay put . They measure slightly larger than American made primers . If I use any of the American made primers in Cheddite hulls they are a loose fit unless you condition the primer pocket first . I haven't had to buy any new Ched primers in a bout 5 years or so maybe they changed them .

Which Cheddite primers are you using ?

I've used Cheddite for oh, I'm not sure, but for 8 or 10 years. I broke my leg 13 days ago so I can't get down in the basement to check. I did a little checking and found the Cheddite primers for foreign use were never imported to the USA, so I was wrong on that count. Here's some measurements:
This should answer some questions. Point A is the measurement at the top of primer. Point B is the measurement taken as close to the flange as possible.
Primer Brand Point A Point B
CCI .239" .241"-
Cheddite .238" .243"-
Federal .242" .241"-
Fiocchi .243" .243"-
Nobel Sport .242" .242"-
Remington .241" .240"-
Rio .245" .244"-
Winchester .236" .242"-
Wolf .238" .242"
I'm not sure what a Cheddite hull measures.

From Ballistic Produces site

Part #
209 Primers
Type & Use:
Box/Case
Diam.
#F616
Fiocchi 616
multi-purpose 209
1000/5000
0.242"
#RIO209
Rio 209
multi-purpose 209
1000/5000
0.245"
#CH209
Cheddite 209
multi-purpose 209
1000/5000
0.242"
#CCI
CCI 209
small-bore & mild
1000/5000
0.240"
#CCIM
CCI 209 Magnum
magnum 209 uses
1000/5000
0.240"
#209A
Federal 209A
multi-purpose 209
1000/5000
0.241"
#R209
Remington STS
multi-purpose 209
1000/5000
0.241"
#W209
Winchester 209
multi-purpose 209
1000/5000
0.2415"

For me the Ched primers fit tighter and work better in Ched hulls than US made primers.

And they're cheaper, the only reason I use them.