Occasional failure to feed

alphabrace · Dec 23, 2010

Hello,
I reload and occasionally I have a FTF with my M&P 9. I factory resize my ammo and length is consistent. What happens is during a string of firing, the slide moves forward but stops short about 1/8 to 3/16". Cannot move slide back so I hit with the palm of my hand the back of the slide to shove it forward. If I am lucky I can then fire the round and it ejects. Sometimes will not fire so I have to repeatedly pull back on slide and eventually it will come open. So where do I start to try to figure out why this happens? When the slide is all but closed isn't the round already begun to line up in the breach of the barrel? And if the slide is not completely closed why can't I pull it back?

Walthernut · Dec 23, 2010

I don't own a pistol as you describe, but here goes.
Does it do it with factory ammo? (this is the number 1 question)
How many times have your cases been reloaded? Could be a burr on the case.
Are your cases full length resized?
Do you trim the cases to the specified length?
When you can't get the pistol to fire and eventually get the cartridge out, is there any deformation of the bullet?
Is the overall loaded cartridge length within spec for each and every round you reload?
These are things you should look into.
Oh, are you shooting lead or full jacketed bullets with your reloads?

Dragon88 · Dec 23, 2010

What dies are you using? Are they in good condition, specifically the sizing ring?

Reinstall your sizing die. The bottom of the die should just touch the shellholder with the ram run all the way up.

What size bullets are you using? They should be .355 for jacketed.

I doubt the cases are too long but measure a sampling anyway to make sure they fall within tolerance.

Ensure you aren't crimping so much that you are causing the cases to buckle. A light taper crimp is all that's needed.

Check the COAL of your final rounds and make sure it is below max. OAL of rounds will vary a few thousands so your target should be at least .010 below max to ensure reliability.

OKFC05 · Dec 23, 2010

Buy a 9mm drop-in cartridge gauge.
Your ammo is out of SAAMI spec, and the gauge will show you exactly where it is too large. Rather than hammer the oversize ammo into the gun, remove the oversize ammo with the gauge before it winds up in the gun.

You're lucky the M&P won't fire out of battery; with some popular guns, you could have a face-full of brass shards by now.

alphabrace · Dec 23, 2010

I think my crimp may have been too much and caused the case to expand at bottom of the bullet. I thought the factory crimp would take care of that. I don't recall if I was crimping when seating the bullet or not. I am using the Lee 4 die set. I need to reload another batch. I am using both copper jacket and Hard lead. I think the problem was with the jacketed. Thanks for you input!

handgunner356 · Dec 23, 2010

Remove your barrel and use it as a drop gauge for your loaded rounds. Another quick check is when you find a round that doesn't want to chamber pull it out instead of forcing it in. You should see marks where it's hitting, offen it's the bullets' overall length and touching the rifling too soon.

Dragon88 · Dec 23, 2010

alphabrace said:
I think my crimp may have been too much and caused the case to expand at bottom of the bullet. I thought the factory crimp would take care of that. I don't recall if I was crimping when seating the bullet or not.

You need to slow way down if you don't recall steps in your loading process. Seat all the bullets then crimp in a separate step. I personally do not like the Lee factory crimp die, but if that's what you have it will work. The "sizing" it does is not meant to mask overcrimping or poor technique. Apply only a light taper crimp to the case mouth. Use your calipers to measure the mouth of the case before beginning crimping, then you can measure precisely how much you are crimping. It only takes a few thousandths.

silvercn · Dec 24, 2010

handgunner356 said:
Remove your barrel and use it as a drop gauge for your loaded rounds. Another quick check is when you find a round that doesn't want to chamber pull it out instead of forcing it in. You should see marks where it's hitting, offen it's the bullets' overall length and touching the rifling too soon.

this was my problem too...
I was not seating the bullet deep enough.
I was using SWC as well...... (bad choice).
I now only use RN and FP bullets... they always seem to cycle.
my 2 cents.//

chuck s · Dec 24, 2010

If the bullet enters the chamber leade it will do as you describe. The leade is the transitional area between the chamber and rifling.

Not only is OAL length important but the ogive shape is as well. That's the curved surface at the nose of the bullet. Not seating a proper shaped bullet will yield the same effect. I have some factory 147gr 9mm JHP that will not chamber in one of my 9mm pistols because of the ogive and leade tolerance stacking. The bullet is being jammed into the rifling because of the ogive shape.

-- Chuck

sgtvilla · Dec 24, 2010

only time I had that problem, we weren't seating the bullet deep enough. It was the first time reloading hollow points so we did it wrong.

SMMAssociates · Dec 25, 2010

Seriously non-expert here

, but I'd also look at the extractor. Is it clean, etc., and not failing to slip over the case rim. You may want to pop it out and clean it. (Randy Lee has a nice video at YouTube - FRE install.wmv.)

(It's about Apex's extractor, but the remove/reinstall is the same.)

Buddy of mine had a problem with cases that had been in a Glock and not properly resized to deal with the somewhat unsupported case head. I don't recall who's die fixed it.... Make sure you don't have the bump!

Regards,

Occasional failure to feed

alphabrace

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Dragon88

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OKFC05

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alphabrace

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handgunner356

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Dragon88

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silvercn

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chuck s

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sgtvilla

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