Production Rimfire Rifles with CIP bores/chambers in the US (Especially semi-autos)?

[renaissanceman]

I've been doing a deep dive into chambers and bore dimensions and have been a bit surprised by the differences between CIP and SAAMI. The chambers are somewhat similar in some dimensions between SAAMI Sporting and CIP, with CIP being much tighter and less tapered. It's tighter and less tapered than a Bentz chamber as well.

On the bores, the difference is more significant:

SAAMI:

Bore: 0.217" +0.002" (0.217-0.219)
Groove: 0.222" +0.002" (0.222-0.224)

CIP:

Bore: 0.2118" +0.0008 (0.2118-0.2126)
Groove: 0.2196" +0.0012 (0.2196-0.2208)

This is a rather large difference in dimensions, with the European spec barrels having much tighter tolerances and deeper rifling.

This got me curious on which rifles (if any) that can be purchased off US shelves have barrels conforming to CIP standards and if they are all bolt guns or if there are some semi-autos in the mix (like the Bergara BXR, perhaps). If European produced rifles available in the US are CIP, this makes sense why many are regarded for great accuracy. I find a lot of 22lr ammo comes in right around 0.222" in diameter, which means it's not squeezing much to get through a SAAMI bore.

Anyone have some insight? I have contacted Tikka, CZ, and Bergara and am waiting to hear back.

 

[grauhanen]

Firearms made in countries that are members of Commission internationale permanente pour l'épreuve des armes à feu portatives ("Permanent International Commission for the Proof of Small Arms" – commonly abbreviated as C.I.P.) adhere to CIP specifications.

Among those members are Austria, Belgium, Czech Republic, Finland, France, Germany, Hungary, Italy, Russia, Slovakia, and Spain. Also included is the U.K., Chile, and UAE. Firearms produced in the CIP member states are proof tested at CIP approved proof houses.

As a result, firearms from manufacturers such as Anschutz, CZ, Tikka, and Bergara follow CIP specs.