This question is about a CAR-15 from Olympic Arms. It is a range toy with a slide fire stock. It has the 11.5" barrel with the 5.5" welded flash hider. The gun is used for rapid fire and does on occasion misfeed during bump fire sessions and more so once it heats up. The gun does not have the M4 style feed ramps and I am thinking that adding them may help. I want to change the upper from a fixed handle to a flat top but I do not want to change the barrel. I am thinking that I can Dremel or hand file the barrel ramps once the new upper receiver is on. Thoughts?