Odd Para FTF isue

[Dave01]

I picked up a Para S16-40 LTD about a month ago (http://www.para-usa.com/new/product_pistol.php?id=12). Yesterday, I went on my second range trip putting 250 rounds through it (500 total). I'm having a failure to feed issue, but the odd thing is, it's only on the last round of the magazine. After 500 rounds, I have not had a single stoppage except on the last round in the mag. I have 4 factory 16 round, double stack, 0.40S&W mags and they have all done it at one time or another. I do not have an FTF on the last round every time; it seems to be somewhat random. The frequency increases the more rounds I put through it in a single trip though.

The last round is entering the barrel at an angle and getting wedged (top to bottom) causing the action to hang open. I'm confused as to why it only happens on the last round. The only thing I can come up with as that the mag spring force on a single round may not be high enough to help guide the round correctly. Empirically, the spring resistance for a single round is much less than that of my Sig 226, 10 round 0.40S&W mags.

Anyone have any thoughts on this? Thanks in advance.

Dave

[flintknapper]

Get some Wolffe "extra power" magazine springs. Should be end of problem.

[Dave01]

So my Para S1640 is finally fixed. I tried the Wolfe extra power mag springs that Flint suggested but that did not solve the issue. I messed around with different ammo also, but that didn't seem to help either (in some cases it was worse). I finally sent the gun back to Para to fix the issue. I sent them a list of observations that I thought might be causing the issue. One of these was that the recoil spring force seemed excessively high. It was very difficult to manually work the action, and almost impossible if the hammer was down.

They evaluated the gun and replaced the recoil spring. They claim this is all that was done. The gun functions perfectly now. The spring force now seems "normal". I'm happy, but a bit confused. How could an overly stiff recoil spring cause FTF's on only the last round in the mag when using Rem UMC and WWB (Blaser brass had an FTF on almost every round...shoots fine now)?

Dave

[Cosmo 9]

This is just a guess but it could have been the combination of an overly stiff recoil spring and your grip loosening up after 15rnds of .40 not letting the slide fully open to catch the back of the last round.

I'm not sayin you have a limp grip just a guess.