If you're describing the slide assembly, check to see if it's getting hung up on the stock. Also, it might be because you have the "tang" on the guide rod inverted. It must be on the barrel side of the stop pin.
nope i have had tried to put it twards the stock side but the spring would get sticky so i put it back the right way. i put my bros stock on mine he has a mini 14 but it still did the same. its a newer one just got it last week. i contemplated filing down the bottom side of the slide assembly cause i took the top of the handguard off and saw it was getting caught up on the barrel where its the biggest in diameter (stainless steel barrel) but i know that would void warranty.
Did you check the guide rod? Pull the stock off, and look where the end of the guide rod rests against the cross pin. The "tang" end of the guide rod needs to be on the upper side of the pin (the barrel side). If it isn't, you will experience exactly the problem you are describing. Don't start filing any parts, and for heaven's sake, don't break out the Dremmel tool!
Here, study the end of the guide rod in this photo. The 1911 buffer is optional, but the photo also shows how the end of the rod must engage the cross pin. It really sounds like yours is upside down...
My Tac 30 does exactly the same thing that you're describing. The "cocking arm" isn't getting jammed anywhere, the recoil spring just needs more oomph while the gun is breaking in. Get an extra power Wolff recoil spring (hammer spring too) and problem solved.