M3 cocking problem

I was shooting my .25 cal M3 and began to have difficulty manually single loading both pellets and slugs; it felt like they were over sized. I examined the ammo and found size not to be the case, and it happened randomly. I did try gently working the cocking lever back and forth and found it helped to get some pellets to slide in effortlessly. I guessed it may be the transfer port causing the pellet to "fall in". So after figuring I needed to stop shooting and check it (of course), the cocking lever locked closed. It will not cock. Before I tear into it, I was hoping someone had a diagnosis and fix for it.

Thanks for reading.
 
I was shooting my .25 cal M3 and began to have difficulty manually single loading both pellets and slugs; it felt like they were over sized. I examined the ammo and found size not to be the case, and it happened randomly. I did try gently working the cocking lever back and forth and found it helped to get some pellets to slide in effortlessly. I guessed it may be the transfer port causing the pellet to "fall in". So after figuring I needed to stop shooting and check it (of course), the cocking lever locked closed. It will not cock. Before I tear into it, I was hoping someone had a diagnosis and fix for it.

Thanks for reading.

Just a guess, your hammer adjustment loosened up enough that your sear will not latch. Or my last issue was a small peice of lead in the slug port and causing a dragging feeling on the probe.
 
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TDK - Is your probe tight? Higher power and/or calibers the probe comes loose pretty quickly. I think the K&L ultra grip probe carrier should be standard.
Thanks, but, yes, the probe is tight.

Headshots - Just a guess, your hammer adjustment loosened up enough that your sear will not latch. Or my last issue was a small peice of lead in the slug port and causing a dragging feeling on the probe.
The cocking lever will not even start to cock. Thanks.

I removed the pic rail, cheek rest, and exposed the cocking rod. It appears to be in the barrel as when I attempt to cock it the cocking rod slightly bows which tells me the jam is at the transfer port/probe. The barrel will not come off. Most likely my original suspicion that the pellet got stuck in the transfer port and now, is hooked to the pellet probe.

To be continued...
 
Sorry, I missed the part in your original post where you said it was locked up. It definitely sounds like a stuck pellet. Can you loosen the probe and take the barrel out with the probe? I haven't done that but with the diameters involved you might be able to do that. Hopefully the pellet is stuck between the probe and brass transfer port on the barrel housing only.

EDIT: Disregard above. It's been a while since I looked at the probe setup. It goes in from the back so that won't work.
 
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I gave the barrel a real hard yank and it broke loose so I was able to remove it. The bottom of the probe was distorted, it was misaligning the pellets. I had to grind off the bottom of the probe at the pellet contact surface, but 80 percent remains. The barrel looks fine. I am back to shooting, thanks for the tips. Weird.

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Indeed strange. Glad you got it fixed.

I want to throw this out here even though it sounds like your problem was different. FX was still sending out M3s with only one alignment pin in the probe holder as of end of 2021. This affects side-to-side alignment. Mine had the probe slightly misaligned and was rubbing as you loaded pellets. I had a spare pin, so I pulled the probe holder, added the second pin and reinstalled. Problem solved.