Been using these for years. May take a little modification to your follower but even that is simple sanding. Use them for IPSC matches and edc. Can't say enough about how well these have held up. Even my oldest extensions are in great shape. Never experienced a failure of any kind. The extensions lock onto the base of the mag perfectly but are still easy enough to remove for cleaning and maintenance. The spring holds its K value even after years of use and being loaded nearly full time. Definitely a buy.