Shares of gun makers Sturm Ruger (RGR) and Smith & Wesson (SWHC) rose Wednesday after President Barack Obama unveiled his plan for decreasing gun violence, which includes banning assault weapons and high-capacity ammunition magazines.

Shares of firearm manufacturers sometimes spike when it seems more likely that tighter gun controls will be passed, because that worry triggers people to buy more guns.

Gun sales have jumped since the December shooting at a Newtown, Conn. school that killed 20 children and six adults. Obama made it clear after the shooting that he would push for stricter gun laws.

Since then, gun dealers around the country have been overwhelmed with demand for firearms. Many have been sold out.