PHILADELPHIA -
A Philadelphia man is grieving the loss of his grandson, killed in Monday night's mortar explosion at the Hawthorne Army Depot in Nevada.
"So many of them..." says 77-year-old Jerome Muchnick, when asked to recall his fondest memory of his 23-year-old grandson, Roger Muchnick, Jr. "Sorry..." he apologizes as he breaks down in tears.
"He was a great kid. I had a great relationship with him. He would text me on my phone. I'd get up and there'd be a text that would say, 'just want you to know how much I love you, grandfather.'"
Muchnick was one of seven Marines who died when a mortar shell prematurely exploded in its firing tube during life-fire training at Hawthorne.
At least seven others were injured in the blast.
Military investigators are still trying to determine whether the accident was caused by operator error or a mechanical malfunction with the mortar.
Muchnick says he was notified of his grandson's death on Tuesday.
"When the news- when my daughter came to my office to give me this news, I just lost it."
Roger Muchnick grew up in Connecticut.
His grandfather says he was a good student and an even better athlete, starring in football and lacrosse.
He entered the military three years ago, as a means to a college education.
"He chose the Marines and he wasn't interested in anything else," Muchnick told FOX 29's Bruce Gordon. "He wanted the Marines and the Marines only."
Muchnick, Jr. served two tours of duty in Afghanistan-- fighting that his grandfather says, left an impact.
"He told me one thing. He said, 'whatever you think a third world country is like, it's twice as bad.'"
But Muchnick never regretted serving his country and the folks back home. Which caused his grandfather to re-think his own awareness of the sacrifice of so many strangers.
"I go into a diner and I see some young soldiers or sailors, I never walk out without thanking them for their service and picking up their check. It just happens now- just because of him."
Muchnick says the military has not yet released his grandson's body, so funeral services will likely wait until next weekend.
Roger Muchnick, Jr. visited Philadelphia often and was a big sports fan- rooting extra hard for the Eagles.
He had three siblings.
A younger brother attended Temple University for a time.
Roger Muchnick, Jr. was one of seven Marines killed when a mortar shell prematurely exploded in its firing tube during life-fire training.
Muchnick, Jr. grew up in Connecticut but visited Philadelphia frequently.
