Here is a description from site selling a 629-6.
"The grip frame is K/L size, and a set of Pachmayrs would make it even more pleasant; the Pachmayrs, however, will not install because their screw centers the mainspring. The Power Port is factory original for this 629 product code 163624. The port tames muzzle flip, of course, even with 300 grain Hornady loads. And it preserves the revolver's aesthetics with the adjacent high partridge front sight. The power port enables sufficient recovery to come close to Jerry Miculek's three second record for twelve rounds. Factory specs are as follows: 629 Classic Model Variant; caliber .44 Magnum and .44 Special; capacity 6 rounds; barrel length 6 1/2 inches; High Patridge front and adjustable black rear sights; Hogue Finger Groove Combat rubber grips; Large N frame with K / L size round butt grip frame; satin stainless finish with beveled thumb latch and case colored .500 MIM hammer and .400 MIM smooth combat trigger; floating firing pin; internal lock with two keys. Overall length is 12 inches; and weight empty is 54.5 oz. Winning buyer will receive the 629 in the photo or one of its identical mates. Own one of these excellent 629 Classics, the series most manageable variant,"
You can see why my question came from that description
