Slide not releasing, need help

[Pido11]

I have a sigp226 in .40 cal. I bought the 9mm conversion barrel from EFK and so far it works except the slide doesn't lock after the last round. Do I have to change the springs? I tried to use reloaded ammo and that does not seem to move the slide al the way so I tried hotter rounds and it works except the last round.

[Josh]

I would guess the 9mm dosent have the power to cycle the slide far enough.

try a weaker recoil spring.

[Gnote]

I've read on Sigforum that the recoil spring needs to be lighter. The only other thing is to make sure your mag is clean and the mag spring is in good condition.

[Pido11]

Just checked everything and it clean. Spring is fine. I guess maybe I need a less heavy springs. Does anybody have any suggestion?

[Kestryll]

Here's an easy way to test if the 9mm round does not have enough 'oomph' to overcome the heavier spring and greater slide mass of the .40 top end.
Remove the magazine, empty the chamber, double check that the mag well and chamber are empty, ah heck TRIPLE CHECK just for the heck of it. Insert an empty magazine into the mag well and seat it in. Now pull the slide all the way back as far as it will go and then let it ease forward under control. If the slide lock catches it the magazine and firearm are functioning correctly. Try this with each of your magazines to ensure that none have a mechanical problem.
If the slide lock does not catch the slide when you ease it forward then you have something not lining up right.

[Pido11]

Here's an easy way to test if the 9mm round does not have enough 'oomph' to overcome the heavier spring and greater slide mass of the .40 top end.
Remove the magazine, empty the chamber, double check that the mag well and chamber are empty, ah heck TRIPLE CHECK just for the heck of it. Insert an empty magazine into the mag well and seat it in. Now pull the slide all the way back as far as it will go and then let it ease forward under control. If the slide lock catches it the magazine and firearm are functioning correctly. Try this with each of your magazines to ensure that none have a mechanical problem.
If the slide lock does not catch the slide when you ease it forward then you have something not lining up right.

Did what you suggest and everything is fine. Locking as it suppose to. Is this mean I need less springs?

[Gnote]

This link may help...

http://sigforum.com/groupee/forums/a/tpc/f/430601935/m/835107413/r/389102613#389102613

[Kestryll]

I would say your test backed by Gnote's link means you need a lighter recoil spring.
Follow Gnote's link to the info on sigforum, there are links in that post thatcan help you find the spring you need.

Here is the link to the Brownells web page that carries the spring you need. It is part 39 in the 16# version.

http://www.brownells.com/aspx/ns/Schematics/SchemMFG.aspx?schemid=832

[Compact45]

slide lock

make sure your thumb is not pressing the slide stop so hard that it
may prevent the follower to push the slide stop upward direction.

JJB

[Pido11]

I ordered the Wolf spring 15 lbs. Should be here in two days. I will let you know if this solves the problem. Thank you all!