Some guy on XBL said having no attachments on your weapon made it more accurate. Is that true?

no.

I wouldn't believe what anyone on XBL said unless I knew for a fact they had some credilibility.

Besides Scrubs, what works for one person might not work for someone else.

I actually did some tests and having no attachment made my reticle smaller . I dunno interesting...

It makes your weapon alittle bit more accurate. But not a huge difference. Attachments like scopes just help to see the picture from far closer, they decrease accuracy abit but alot more obviously when moving. They're great for single shots but on burst and auto they spread too much. Laser sight just increases your reach out and touch someone (range).