STI Trojan 9mm slide lock issue

[SourPatch]

I just bought an STI Trojan in 9mm and 6 Wilson Combat mags. It wont reliably make slidelock with an empty mag. I thought it was just my light reloads, but it happens even with factory loads. Maybe a lighter recoil spring?

 

[Alpo]

could be the mag follower interface with the pistol.

 

[NHT3]

Generally Wilson mags are as good as it gets but if it does it with several different mags I would consider at least 124GR bullets. Also possible that previous owner was running really hot loads and installed a heavier recoil spring. Make sure you have the correct recoil spring and go from there.

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[Opie]

Does it lock back on an empty mag consistently when you cycle it by hand?

 

[Grelber]

Had the same gun, it preferred Trip Cobra mags, can't remember if it was jams with feeding or other issues that got me to using TC's, have slept since then.

Recoil spring seems unlikely but if brass ejection distance is very short then maybe. Other thing, if somebody put grams followers in your mags or mags are pretty dirty and follower does not fully rise sometimes.

 

[rhino]

I just bought an STI Trojan in 9mm and 6 Wilson Combat mags. It wont reliably make slidelock with an empty mag. I thought it was just my light reloads, but it happens even with factory loads. Maybe a lighter recoil spring?

This is a common thing for 9mm 1911s. I've been shooting one a lot longer than most, and it's not unusual regardless of brand of gun or magazine.

You might be able to tinker with the recoil spring weight and getting them to lock back on empty, but if the fun functions well otherwise, I would advise to leave it alone and accept that it won't lock open consistently. Changing the recoil spring weight and/or the mainspring weight might fix the lockback problem, but it might also result in the gun not functioning otherwise consistently. To me, it's not worth it.

Also, failing to lock back is more common with 10rd mags, regardless of brand, than for any of the 9 round magazines. Before you do anything else, if you are dead set on having the slide lock back when the mag is empty, try some 9 round magazines. The best on the market are the Springfield mags designed by Rob Leatham and manufactured by Metalform. It's very possible that your slide will lock back with those without making other changes that might affect reliability.

 

[wcd]

I just bought an STI Trojan in 9mm and 6 Wilson Combat mags. It wont reliably make slidelock with an empty mag. I thought it was just my light reloads, but it happens even with factory loads. Maybe a lighter recoil spring?

Had the same issue with my STI worked great with STI mag 9 rounder, I wanted 10 rounds so purchased a 10 round Mcgar mag pos, eventually ordered 2 CMC power mags works great no issues locks back every time.

 

[churchmouse]

How tight is the slide lock in the frame. Th follower in the mag has to lift it into position in a narrow time window. It may need some tuning.

Rhino hit it.