Any known way to reduce or eliminate that scrapping/screeching buffer spring noise?

Replace it. It shouldnt be doing that. You sure you've got the right spring in there? Commercial or Mil Spec? Try wiping it down with a good gun oil. None of mine make any noise.

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Dyin ain't much of a livin

It is the stock m&p Sport spring. I have 1000 rounds through the gun. It doesn't sound broken, just noticeable.

It's normal, don't worry about it.

Cool, thanks.

A little CLP will probably quiet it down. Just don't over do.

Normal. Best fix I know -- a light coat of grease on the spring.

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Pisgah

I have a syringe of this...

Gun Grease - Synthetic Gun Grease

Correct. Perfectly normal. Be advised that grease likes to hold onto ****.

When you get used to the "sproing" you can tell if you're out of ammo, or if you had a squib or other load malfunction just by the difference in the sound it makes. Just sounds weird when you first notice it. BTDT

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ΜΟΛΩΝ ΛΑΒΕ

^^ Exactly. The sproing is a confirmation that your rifle is functioning normally, or an indicator that something's wrong if the sproing sounds different.

I use the spring noise to tell me the magazine is empty. When it doesn't ring, I need to reload.

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*Aim small, miss small...

Funny this issue showed up her and at the other forum. This weekend I got to shake out the new DPMS carbine, and side by side it with the Sport. I noticed the Sport spring clunking in the tube under my ear for the first time. I shook the rifle 2 times, all seemed fine, and we went back to shooting. It takes a cleaning and a couple rounds before the spring starts to sing to you. FWIW, my Sport hit 3k rounds this weekend!!! Accuracy is still good. No signs of any unnatural wear; in fact, the wear patterns seem to be slow to even show up. I think I like the Melonite. The BCG cleans up pretty well with it, and the spring for the ejector was really clean in there. Good to go.

I usually don't notice the 'sproing' noise unless I'm shooting low-grade ammo...Like Herter's or other ammo that's on the ragged edge of running the gun.

If I shoot NATO ball or better grade commercial .223, stuff that runs the rifle a bit 'crisper', really don't hear the noise.

Ammunition loaded to a lower pressure will cycle the action less vigorously. This will make the clunk of the action slower and the buffer spring noise more noticeable.

M855 is the only thing I have shot with.

Overrun green tip is a little more expensive, but it's excellent ammunition for sure.

When I got my first AR, that "sproing!" sound irritated the **** out of me, as I was used to mostly bolt rifles. So... I put in a pneumatic buffer. It worked great and then I started to get some doubling, or bump-fires, which I didn't like one bit. My gunmith, who's an AR guy from way back, said put the standard spring back in, as the buffer was altering the cyclic rate and probably causing the problem. Since I put the regular spring back in, no problems.

Don't think about messing with a good thing.... the "sproing" means it's working like it should!