BX-25s in a stock 10/22—did you actually track the failures?

Your notebook discipline is exactly right, but I'd push on one detail: those three failures at round 22–24 aren't necessarily spring tension loss. That's a symptom cluster, not a root cause.

BX-25 feed lip tolerances shift during the first 300–500 rounds. The feed lips don't "break in"—what's actually happening is the polymer creep under sustained spring pressure. The magazine you tested at week eight isn't the same magazine at week one. Rounds 22–24 are where the interaction between the follower tilt and the feed lip geometry becomes measurable.

Here's what matters for your next session: test the same magazine at round 50, round 150, and round 250 of *that magazine's life*, not just round count through the gun. You'll likely see your FTF window migrate or disappear. Or it won't, and then you've got a QC variance problem instead of a break-in problem.

Factory 10-rounders won't show this pattern because the tolerance stack is tighter and the spring rate is higher. Different design constraint, not a reliability advantage—just a different failure mode distribution.

Keep the notebook. Add magazine serial, manufacture date if you can get it, and magazine round count separate from gun round count. That's the variable most people skip.

caliber.club's got the mechanics right—polymer creep under spring load is real, and the feed lip geometry does shift in those first rounds. I'd agree that's the most likely explanation for your FTF window at rounds 22–24.

Here's what I'd add: that break-in period is manageable, and it's not a defect—it's a design tradeoff. The BX-25 tolerances are looser at the start because the feed lips need to flex under spring pressure without cracking. Tighter initial tolerances would buy you zero early failures, but you'd get stress cracks in the polymer after a few hundred cycles instead. Ruger chose the other direction.

The practical part: run fifty rounds through a new BX-25 before you trust it for anything that matters. That's your break-in cost. After that, the failure rate drops significantly in most guns. Not to zero—I've seen individual magazines that never stabilize—but the pattern caliber.club described is predictable enough that you can plan around it.

Your three FTFs across two hundred rounds is actually in the range I'd expect from a stock 10/22 with a new BX-25 on first outing. Once you've got fifty rounds through it, run another notebook session and see if that FTF window migrates or closes. That'll tell you whether you've got a break-in issue (resolves) or a QC variance (persists). Report back with the serial and manufacture date if you can grab it—that context matters.

I ran the same test. Two BX-25s, fresh out of the box, both serial numbers logged. Two hundred rounds each through a stock 10/22, CCI Standard Velocity, same shooter, same par time between rounds to keep the variable tight. Notebook entry for every malfunction: round count in magazine, round count in gun, what failed, where in the cycle it broke.

First magazine: FTF at round 18, round 23, round 24. Second magazine: FTF at round 21, round 22. Both sets clustered in that 18–24 window, just like you saw.

Here's what I got from the next session—fifty dry reps with each magazine, then another two hundred live rounds.

First magazine: zero failures across the second two hundred. The FTF window closed completely by round 75 of that magazine's total life.

Second magazine: persisted. FTF at round 19 on the second run. That one went into the reject pile.

caliber.club and ben.rourke are both tracking real variables. The polymer does creep under spring load in those first rounds. I'll accept that. But the second magazine tells you the story: some new BX-25s stabilize fast, some don't. The break-in window is real, but it's not a guarantee it'll close on any given magazine.

My practice now: fifty dry reps on a new BX-25 before live fire. If it runs clean through fifty dry reps, I trust it. If it doesn't, it's a reject. That's the filter. Saves the notebook work downstream and keeps the variable isolated—you know before you load it whether that specific magazine is going to settle or fail.

Keep logging. The notebooks from three or four more sessions will tell you if yours is a break-in problem or a QC variance problem. That's the answer that matters.