I have this same issue on my G34. Turns out my right thumb is either riding the slide release or interfering just enough to keep it from engaging the slide. I removed the extended slide release and it helped but still happens occasionally. It doesn't bother me enough to try and change my grip.
I like it! I am constantly tripping over and/or moving my tumbler around the garage floor. Never thought about putting together a dedicated tumbling station. Smart!
Some of my best results came from being loose and having fun. That did not mean I forgot entirely about the plan or the task at hand, just that I was more relaxed and less focused on the outcome.
Welcome Rick!
Join us out at Cavern Cove in Woodville, AL with the Rocket City Practical Shooters. You can shoot or watch anything from USPSA, IDPA, Speed Steel, 3Gun, etc. Pick your poison. Great group of people and a ton of fun.
Shake it off and remember, you are there to have fun. There will be plenty of other classifiers for you to burn down and just as many (if not more) for you to completely tank.
Match starts at 10:00 cst and is $15. Pre-registration link below:
https://clubs.practiscore.com/rcps-uspsa-13-june-2015/register
I look forward to seeing you there!
I'm curious of round count too. Also, what hand guard are you using?
I have used the Troy Alpha rail and Samson Evo rail. Both of these have been great and I have not experienced them "heating up".