Could FMJ-FN vs FMJ-RN really cause all this?

SuperTrooper

SuperTrooper

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On one of my 4th of July sales I neglected to notice that the Winchester Target & Practice 9 mm 115gr FMJ rounds in the order weren't the usual RN that I usually order, but were instead FMJ-FN (flat nose). With them today I experienced malfunctions, many malfunctions. My stone reliable P320 AXG Legion today threw a dozen or more live round stovepipes, and my P365 X-Macro locked the slide open after each and every round. When I switched back to my usual RN 115gr FMJ they both returned to their regular flawless operation, as with my 127gr poly reloads. I do see these FN are significantly shorter OAL than all my other rounds. Could the difference in shape, or OAL really cause all this, or did I get 250 bad rounds? I've never seen these short Winchester 115gr FMJ-FN rounds before - what are they for?
 
MisterEd said:
Range practice, target shooting, plinking etc.

The flat nose cuts cleaner perforations in paper targets, making hits easier to see at a distance.

You didn't get 250 'bad rounds'. I'd say your guns simply do not 'like' the shorter, FN bullets.
Click to expand...
My chronograph shows over 600 fps in variations. 6 pistols, none would digest them, are they for a revolver?
 
SuperTrooper said:
are they for a revolver?
Click to expand...
Well, no 9mm ammo is specifically designated for a revolver so maybe it is just crappy ammo with a wide variation in powder charges. 600 FPS seems pretty excessive but I guess it's a possibility.

I haven't bought any commercial ammo in probably 15 years, and that was just one box of .30-30 to go shoot a Mod 94 I had just traded for.

I reload everything (and coming up soon on 50 years of doing so!) so I haven't ever had the experience of 'bad' ammo.
 
My reloads are usually within 10-15 fps, I hear you. I just got one of those radar chronograph deals that records everything, I'm still pooring through the session data, but it appears that the only thing that looks amiss are the 115gr FMJ-FP.... Many were under 1000fps, way under.
 

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