Need .22 advise

AR/M4 AR Pistols & Pistol Caliber ARs
1

I have an existing upper receiver and want to buy a barrel and BCG for .22. I have no knowledge of the operation of the conversions.

If I have a barrel cut down to 7.25, does the CMMG conversion kit require a gas port drilled or will it operate without it. Thanks

2

the gas port has no effect on the bolt in a .22 conversion, it has a built in spring on the bolt.