S&W M&P 40 fullsize, new Storm Lake barrel not feeding reliably

[cycle61]

Per the title, just received a Storm Lake threaded barrel for my M&P 40, and most of the ammo I've tried has been hanging up on the feed ramp. Just hand cycling rounds, slow release of the slide would jam nearly every time, and a slide drop from locked position resulted in about 20-30% jamming. The most reliable were the WWB 165's (third from left) but all the ammo I tried hung up multiple times per magazine. Dropping a round into the chamber with it out of the gun doesn't indicate any binding or jamming, slides smoothly in and out. The markings on the ramp in this picture are strictly from hand cycling maybe 100 rounds total through it including copper plated handloads.

The gun has always run flawlessly with it's factory barrel, and has never had a failure of any kind with any ammo.

Dremel polish and gentle radius needed, go run a few hundred rounds and see what happens, or do I have an actual problem here?

Read More

 

[JustSomeGuy]

To my old eyes, that ramp does look kinda rough. I'd polish it and see if that smooths out your feeding issue.

Just an old guys .02

 

[Lazyfaire]

Don't slow release your slide. Screws it up (feeding) almost every time.

Do you have problems with it on every cartridge? If you have 5 in a mag, how many jam up?

 

[cycle61]

Tried a bunch of different ammo, the WWB was the closest to reliable. I tried the slow feed and obviously it was better when doing a slide drop, but still 2-3 per magazine out of ten would jam.

Gonna give it a polish and try again. Also may see if I can find some ball ammo.