Well I went to the range today to run some Speer Gold Dots through my guns to check for function since I havent carried these. My new Kahr CW 45 gobbled up the 230 grain GD's like M&M's and put them right on the POA. 50 flawless rounds in the Kahr Nice, tweek the CT laserguard for them at 7 yards, done on that gun for today. I had two boxes of Speer 230 Gold Dots so I whipped out my trusty G21 (early model) to try some Gold Dots and replace my aging hydra shocks. The gun failed to feed the last round. Basically the round was pointed about 10 o clock with the nose in the edge of the chamber and the rim on the mag follower. It fed fine with more rounds but not the last round. I put two rounds in the mag a half dozen times with the same result. So I figured maybe its a Gold Dot thing. Nope put my Hydra Shock in last with the same result and also a Winchester Silver Tip. Only a FMJ would feed the last round. Now I only brought one magazine to the range for the 21 and its my carry mag and stays loaded 24/7. So I am thinking the spring has became weak and or the follower is worn. I sent my gun back to Glock years ago to have Trijicons installed and they did rebuilt this mag and changed the insert style.They said upon full compression with a fully loaded mag the springs coils were binding up or something. I never got that revised insert style for my other magazine and just made sure to carry the new style one. Here is what my two hi cap mags look like below. Notice the bodys are different with a U notch on one and a squared notch on the other. But what I am trying to figure out is the difference in the magazine insert that locks the base plate on. Here is a pic of the magazine that was used and had the feed problem. Notice the insert style. Here is a shot of that insert from another angle. and last my other 13 round mag with sqaured notch on the body and a flat style insert At this point I think the spring is just weak and not forcing that last round up fast enought to feed. So I will replace the spring and follower and recheck. Also I will check my other mag next weekend for function. Are current 13 round G21 mags using the flat insert or one like the restyled one here? Or something else all together? I think its time to order a couple new magazine but will rebuild this one also. Thanks Dobie.