bugsy

I don't have an M&P Pro 9, but I have seen this same problem when I was developing my load for my CZ 85C. I did not change powder, bullet weight. The culprit: OAL. With your barrel on hand, try fitting your seated load, un-crimped. The bullet should barely touch your rifling, and at the same time, your bullet should seat flushed in the chamber. Then, do a light crimp, enough to remove the bell when the bullet is seated. Try several loads of varying OAL's. and choose the OAL that suits your barrel length. I might be wrong or missing few parameters. But this worked for me. Safe shooting!

I had similar problem before. Of 1000 rds reloaded, I might have at least 20 rds of no-fire scenario. A second pull (DA) of the trigger ignites the round. I am thinking of a bad batch considering I am already using an extended firing pin on my CZ 85C. I will be switching to Federal SPP after stock of about 900 rds re-loaded and another 800 WSPPs.

Sammy, I use 125 gr LRN and I start with 3.2 gr Titegroup, and tried up to 3.8 gr. Though I have not used a Chrono to check for Velocity and Power Factor, b I liked the accuracy and recoil @ 20 yds loading 3.4 gr for my CZ 85 Combat. 3.6 gr is also close to the accuracy and recoil. OAL about 1.1" Since you are using 124 gr, try a starting load of 3.2 gr, 5 rounds at a time and work your way up. Do not exceed recommended max load by the manufacturer. Safe shooting!

Ooooops.... I did not pick "Looks for Range" as my Member Title. I don't know how it happened. My apology to Judge Crater. How do I edit this?

Bullseye and Titegroup 3.2-3.6 gr for 125 gr hardcast. Play around with OAL based on the chamber length.

Hello.... I'm from the great white north (Canuckstan) and new to this forum. I've seen this keyholing and found the hard way that this partly relates to OAL. What I did before crimping was to drop the completed round into the chamber. Make sure the slug barely touches the rifling. This normalizes the pressure during ignition and bullet contact with the rifling. By the way, how thick is your target? Are you using paper taped/stapled to a cardboard or a cardboard? Make sure the target is properly supported from the back. If not, you will get some keyholing which is a false impression of what you should get. Safe shooting and enjoy reloading.