Homer Talley tells TMZ Eric, an 11-year vet for Boulder PD, was a strong advocate for gun rights, and had an AR-15 he often used for target practice. Homer's seen the debate erupt over reforming gun laws, and although this tragedy cost him his son, he doesn't blame gun access ... and doesn't think Eric would either.

He told us, "My son would have been deeply offended to know his death would be used to promote gun control. Before he was an officer, he enjoyed shooting."

Of course, that's the big discussion now in Washington, D.C., as it usually is after a mass shooting. President Biden called for an outright ban on assault weapons Monday ... shortly after the Boulder massacre that killed Eric and 9 others.

While Biden, many lawmakers and a large majority of Americans feel banning AR-15's and similar weapons would deter these tragedies -- Eric's father isn't so sure. He calls Ahmad Al Aliwi Alissa's alleged attack "a senseless act and that is just it. The situation [Eric] found himself in wasn't one that the government could protect him from."

He adds, "Just because some wacko goes around shooting people doesn't mean guns need to be taken away. You can't take away enough guns to protect this country."

Now, Homer also says he's all for common-sense gun laws, "but to take away that freedom completely is something I am against and my son was against." Of course, therein lies the debate ... what is "common sense" when it comes to guns?

Officer Talley's comrades paid their respects during a procession Wednesday, and interestingly ... Homer says he's already letting go of his anger over Eric's murder, telling us, "My family and my son are people of faith, we understand forgiveness and that is necessary for not just the shooter, but for ourselves."