School me - CZ 712 Semi Auto magazine tube springs

**DJ Vier** · 12-09-2016, 12:34

I have a CZ 712 (4 +1 standard configuration) and I added a Briley +5 tube to it (for a Beretta).

I had some issues with the follower getting stuck where extension meets the standard tube, but a gunsmith sorted that out for me.

I ran 2 x tubes cleanly through the gun a week or so ago, but on the 3rd tube it stopped feeding again. On taking it apart the follower passes cleanly through but it seems as if the spring is getting coiled up and hence does not feed the last few shells.

I measured the diameter of the supplied spring and the outside diameter is 17mm but the tube inside diameter is 23mm. The standard one on the +4 configuration is slightly larger - 18mm.

The smaller outside diameter could be be leading to the spring compressing into itself and getting fouled. I have 2 solutions in mind:
1) make the existing spring slightly shorter
2) get a new spring made up where the Outside diameter is slightly larger, say 21/22mm and make it slightly shorter than what I have now

I have not done either as yet, as I would like to get some info before I make changes.

**KillerD** · 12-09-2016, 13:56

I had the exact same issue with mine this morning. I haven't had the end of the original Magazine tubes lip removed yet so it could quite possibly be the follower catching that lip and causing my issue. The spring supplied with my Extension tube is also very long. I haven't checked the spring diameter as yet though. I will be following this with interest.