Was out shooting yesterday with my G29 and Witness. Just because I loaded 10rds DT 200gr hard cast 40s&w in a 10rd G29 mag and worked the slide on all 10 RDS and all ejected fine. Am I able to fire these 40s&w RDS safely through a 10mm barrel in my G29?
Many have shot the 40S&W in their 10mm barrels without incident, just be sure to inspect for any bullet material that my stick at the end of the chamber cut and clean up (carbon and soot) before using 10mm again. Be aware you may experience the striker kicking the casing off the extractor (may never happen, but it doesn't mean it can't).
Good luck!
Next time out I am going to give it a try
Almost certainly not an issue.
On the other hand, for the price of three boxes of decent ammo, you can get a Lone Wolf 40 S&W barrel for your G29, and drop the "almost".
:P
http://www.lonewolfdist.com/Detail.aspx?PROD=156041
If it were me, I would play it safe and buy a conversion barrel and then you can shoot lead safer as well.
Fired 4rds as a test with 0 issues
The only issue with Lead in a Glock barrel is not cleaning any lead out before shooting copper jacketed. If your lead is properly sized with a good alloy, you should have no problems anyway.
Honestly I would just upgrade to actual, 10mm hardcast. Probably, uw, bb, pb.