FTF in Sigma 40

[tionico]

can't quite get at what's up.

Used Sigma 40, I've got four different factory mags, checked that the firing pin/striker is free, not hanging up. Gun has some use, but is not worn out by any means. On occasion (somewhere around twice per mag) a round will fail to feed. Happens with me (fairly new to autoloader pistols) and another shooter, VERY experienced with autoloaders. The round tends to hang up by the nose hitting on the lower edge of the barrel ramp. Slide comes forward, jams round between the ramp and slide face. If I pull the slide back to clear, shake a bit, the round will usually rise up and ride the ramp up and feed. It might feed properly for five or six rounds, might finish the mag, might jam next round.

Slide spring doesn't seem to be weak and flabby, the mags all seem to have strong springs, no jams or roughness. Ten round and fifteen round mags behave the same. It does not seem to be relative to any particular mag. Slide is free, all is clean, makes the pistol a bit on the unreliable side of things... I sure would not want to have to depend on it for my life..... or anyone else's.

I am considering replacing the slide spring.. can't be too much money, maybe a hassle to get, but may well be a good investment anyway.

ANy further thoughts? Ideas? Suggestions? I otherwise like the gun..... but this behaviour, if not changed, could well earn this little fellow a one way ticket out of my life......

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[deadeye]

I had that issue until I polished the machined grooves out on the ramp,then no more problems. This only happened with Gold Dots for me though, would catch on the rim of the hollow points.

 

[tionico]

the ramp on this one is pretty smooth, few if any significant tooling marks.

Using Blazer aluminium cartridge FMJ with flat nose, and also Liberty brand FMJ FN. Tried a load of handloaded ammo, cycling the slide manually but not firing any. Same thing... and about as frequently as with the factory ball ammo.

It seems as though the rounds aren't being tipped up enough in the nose to make the shoulder of the flatnose rise up far enough the flat nose doesn't hit the bottom of the ramp and stick there. The nose does not rise up far enough to actually enter the ramp.

Thanks for the input...... and I'll take another good hard look at that ramp.