Feed issue with M&P .40 FS

[S&W-Admirer]

At the range yesterday, my M&P .40 FS had trouble feeding some of my reloads. When there was only 1-3 rounds in the mag, the round would get stuck with the nose in the top of the chamber when releasing the slide with the slide release or sling shot method. Pushing the slide forward would usually chamber the round. It didn't occur when the magazines had more rounds in them.

Consider:
1. It happened with two different newer magazines that have proven reliable.
2. The .40 brass was bulge busted and sized properly and completely in spec. The crimp was in spec. All rounds passed the plop test. My Glocks had no trouble feeding the exact same ammo.
3. The recoil spring has less than 300 rounds on it.
4. The pistol was clean and well lubed. The pistol has about 300 rounds through it. It has been completely reliable in the past.

My only guess would be the OAL of the rounds was 1.130-1.135", toward the maximum end of OAL for .40. Maybe the flat conical shape of the Berrys plated bullet?

Any ideas?

 

[AGoyette]

Some guns don't like different shaped bullets. I used to have a competition gun that hated semi wad cutters. It loved round nosed bullets though.

 

[blackxpress]

I had that problem with mine the first 50 rounds I put through it. That was with 165 grain Fiocchi FMJ. As soon as I finished that box and switched over to 165 grain PMC the problem cleared up. Since that day I've put several hundred rounds through it, all different brands, and it has functioned flawlessly. I haven't tried any more Fiocchi so I don't know if it was an ammo problem or not but that's my assumption.

 

[NCooper]

My 40c & shield 40 had issues with some fiochi 170gr fmjtc which happened to be a flat nose bullet.

It would do the exact same as you describe, usually with in the first 3 rounds of a mag and again in the last three rounds of the mag.

I now know not to buy that ammo again. I'll stick with speer lawman and gold dot with some federal black eagle or what ever the red and black boxed ammo with the eagle is.

I believe the problem is flat nose and just a little shorter round.

 

[mistahd]

My 40c & shield 40 had issues with some fiochi 170gr fmjtc which happened to be a flat nose bullet.

It would do the exact same as you describe, usually with in the first 3 rounds of a mag and again in the last three rounds of the mag.

I now know not to buy that ammo again. I'll stick with speer lawman and gold dot with some federal black eagle or what ever the red and black boxed ammo with the eagle is.

I believe the problem is flat nose and just a little shorter round.

+1. My Shield 40 would not feed this at all. My M&P Pro 40 4.25" ate it up.

 

[jwalts27]

what grain bullets you pushing? I would seat a little deeper. Alot of people who use a long OAL with flat points have your same issue. Your OAL is more than likely the problem. I seat all my 165g and 180g at 1.125 with no issues at all.

 

[yogi]

cut your loses and buy an H&K or glock.

 

[Rastoff]

It could be an OAL issue. Seating .40 bullets deeper makes me nervous though. They are already a high pressure round.

Have you tried polishing your chamber? That helped me when I had a similar issue with my .45 M&P.

 

[WR Moore]

The flatpoint truncated cone shape pretty much mimics the profile of much JHP ammunition. I'd suggest measuring the OAL of some factory JHP ammo (Federal Classic is a good example) and then duplicating that with your reloads.

By pushing the bullet forward, the nose of the bullet is contacting the chamber roof at a point that puts the cartridge at a steeper feed angle.

If it feeds factory and not your reloads, that's what we call a "clue".

 

[S&W-Admirer]

I fired 25 rounds of Federal 180 grain ammo through the M&P .40 this afternoon, trying to duplicate what I was doing before, and had no feeding issues. It must not have liked the truncated cone shape of the bullets of my reloads or the longer OAL. I'm going to shorten the OAL from 1.135" to 1.125" on the reloads and see how it feeds. The Federal bullets were round with a flat nose.

This M&P .40 is very accurate and fun to shoot. The recoil doesn't bother me at all.