WASHINGTON — Editor's note: List of guns at bottom of story.
On one side were pegboard panels mounted with various assault rifles and semi-automatic weapons -- including a Bushmaster similar to the one used in last month's Newtown school massacre.
Behind the stage stood police officers supporting a renewed ban on such firepower. One by one, victims of gun violence told their brief stories and expressed support for a new federal ban being proposed by Sen. Dianne Feinstein on some assault rifles and semi-automatic weapons.
Almost six weeks after the Connecticut shooting rampage that killed 20 first graders, Feinstein said she will introduce her measure later Thursday, with Reps. Carolyn McCarthy of New York and Ed Perlmutter of Colorado doing the same in the House.
Feinstein's proposal would upgrade an assault weapons ban that expired in 2004 and also outlaw ammunition magazines that hold more than 10 rounds.
She said the goal is to "dry up the supply of these weapons over time."
"These massacres don't seem to stop," the California Democrat lamented, listing notorious rampages of past years known by the lone name of their locations -- Columbine, Virginia Tech, Aurora, Tucson and Oak Creek.
"We should be outraged at how easy it is" for attackers to get hold of the semi-automatic weapons or large-capacity magazines used in those slaughters, Feinstein told the event at the U.S. Capitol that she organized..
Her legislation is opposed by the nation's powerful gun lobby, led by the National Rifle Association. That means that despite a push by the White House and Democrats for tougher gun control steps, Feinstein's full measure is given little chance of winning congressional approval.
In a statement on Thursday, the NRA said Feinstein "has been trying to ban guns from law-abiding citizens for decades."
"The American people know gun bans do not work and we are confident Congress will reject Senator Feinstein's wrong-headed approach," the organization added.
Feinstein acknowledged that enacting a ban was "really an uphill road," adding: "If anyone asks if we can win this, the answer is we don't know, because it's really uphill."
She then made a plea for people to call their senators and House members to declare "enough is enough," adding that a mobilized public is "stronger than the gun lobby."
President Barack Obama called for renewing the assault weapons ban as part of his package of gun control proposals announced earlier this month in response to the December 14 Newtown school massacre and overall gun violence in America.
Feinstein's measure would stop the sale, transfer, importation and manufacture of more than 100 specialty firearms and certain semi-automatic rifles, as well as limiting magazines to 10 rounds or less, she said. Not all of the weapons in the bill meet the technical definition of assault weapons.
The restrictions would not apply to guns owned before enactment of any law. Feinstein noted her proposal exempts from the ban more than 2,000 models used for hunting or sporting purposes.
"They are by make and model exempted from the legislation," she said, adding that the old ban had 375 such exemptions.
Those exemptions were an apparent effort to garner support for the measure from conservative Democrats and others expected to face fierce lobbying by the NRA and constituents.
Supporters of more gun control acknowledge the constitutional right to bear arms, but argue that rifles capable of firing multiple rounds automatically or semi-automatically exceed the reasonable needs of hunters and other gun enthusiasts.
They also contend that high-capacity ammunition magazines provide the capability for mass shootings such as the Newtown massacre.
Opponents contend the Second Amendment forbids the government from this type of limit on weapon ownership by citizens.
They worry that such a weakening of gun rights would signal a shift that would leave citizens defenseless against criminals and, some also argue, against potential future government tyranny or abuse. Instead, the NRA has called for increasing armed guards at schools to protect students.
Speakers at the event organized by Feinstein rejected arguments that anyone beyond the military or law enforcement officers needed such firepower.
"How are you going to hunting with something like that?" asked Philadelphia Police Commissioner Charles Ramsey, pointing to the assault weapons displayed to his left. "You kill something, there's nothing left to eat."
He drew on his experience as a police officer in Chicago, Washington and now Philadelphia, noting the proliferation of sophisticated weapons and large-capacity magazines.
Ramsey said he could not remember the last time he went to a crime scene and saw only one shell casing on the ground.
The continuing bloodshed on the nation's streets -- with dozens dying every day from gun violence -- should be enough evidence to overcome the past inability to get gun control legislation enacted, he argued.
"If the slaughter of 20 babies does not capture and hold your attention, then I give up because I don't know what else will," Ramsey continued, pointing his finger in the air.
Both Ramsey and Democratic Sen. Charles Schumer of New York emphasized that Feinstein's proposal would allow law-abiding gun owners to keep their weapons, challenging a conservative talking point that the government seeks to take away guns.
"We're not trying to seize everybody's guns, but c'mon, we need reasonable gun control in this country, or guess what, it will happen again," Ramsey said.
At Feinstein's request, people who were injured or lost loved ones to gun violence, including several from the Virginia Tech massacre, then offered their support for her efforts.
Some told of losing a parent or child. Others described how attackers inflicted carnage so quickly.
Pam Simon, a staff member to Rep. Gabrielle Giffords of Arizona, said she was a few feet away from the congresswoman on the day both were shot outside a Tucson grocery store.
"On that day, 30 bullets were delivered in less than 30 seconds," Simon said.
Some of the weapons on display Thursday are currently against the law in the District of Columbia, and Democratic sources told CNN that Feinstein coordinated with police on being able to have the guns there.
NBC's David Gregory was recently investigated for holding a banned ammunition magazine on the network's "Meet the Press" program broadcast from Washington. No charges were brought in that case.
Obama's proposals include expanding and strengthening background checks on gun buyers to ensure all sales include screening to prevent weapons from going to criminals and the mentally ill.
While the gun lobby has indicated support for some improvements in background checks, it remains opposed to other steps, saying they won't prevent criminals from getting weapons.
Instead, gun advocates urge tougher enforcement of existing laws and making criminals serve their full sentences.
Vice President Joe Biden led a panel assembled by Obama to examine gun control steps after the Newtown shootings, which sparked a fierce public debate over how to prevent such mass killings. Biden's recommendations formed the basis of the package of proposals Obama announced this month.
A recent CNN/Time Magazine/ORC International poll indicated that Americans generally favor stricter gun control, but they don't believe that stricter gun laws alone would reduce gun violence.
In announcing his gun control package, Obama also signed executive actions that call for tougher enforcement of existing laws and require federal agencies to provide data for background checks.
New York state recently enacted a series of new gun regulations, the nation's first since the Newtown shootings. Ten other states are reviewing some form of related action.
Listed below are the proposed guns to be banned in the U.S., according to the Washington Examiner  :
AK, AK-47, AK47S, AK-74, AKM, AKS, ARM, MAK90, MISR, NHM90, NHM91, Rock River Arms LAR-47, SA85, SA93, Vector Arms AK-47, VEPR, WASR-10, and WUM, IZHMASH Saiga AK, MAADI AK47, and ARM, Norinco 56S, 56S2, 84S, and 86S, Poly Technologies AK47 and AKS, All AR types, including the following: AR-10, AR-15, Armalite M15 22LR Carbine, ARmalite M15-T, Barett REC7, Beretta AR-70, Colt Match Target Rifles, DoubleStar AR rifles, DPMS Tactical rifles, Heckler and Koch MR556, Olympic rms, Remington R-15 rifles, Rock River Arms LAR-15, Sig Sauer SIG516 rifles, Smith & Wesson M&P15 Rifles, Stag Arms AR rifles, Sturm, Ruger & Co. SR 556 rifles; Barrett M107A1; Barrett M82A1, Beretta CX4 STorm; Calico Liberty Series; CETME Sporter; Daewoo K-1, K-2, Max 1, Max 2, AR 100 and AR 110C; Fabrique Nationale/FN Herstal FAL, LAR, 22 FNC, 308 Match, L1A1 Sporter, PS90, SCAR, and FS2000, Feather Industries AT-9, Galil Model AR and Model ARM; High Point Carbine; Hk-91, HK-93, Hk-94, HK-PSG-1 and HK USC; Kel-Tec Sub-200, SU-16, and RFB; SIG AMT, SIG PE-57, Sig Sauer SG 550 and Sig Sauer SG551; Springfield Armory SAR-48; Steyr AUG; Sturm, Ruger Mini-14 Tactical Rife M-14/20CF; All thompson rifles including the following: Thompson M1SB, Thompson T1100D, Thompson T150D, Thompson T1BSB, Thompson TM1, Tompson TM1C, UMAREX UZI Rifle; UZI Mini Carbine, UZI Model A Carbine, ad UZI Model B Carbine, Valmet M62S, M71S, and M78; Vector Arms UZI Type; Weaver Arms Nighthawk; Wilkinson Arms Linda Carbine.
All AK-47 Types including the following: Centurion 39AK pistol, Draco AK-47 pistol, HCR AK-47 pistol, IO Inc. Hellpup AK-47 pistol, Krinkov pistol, Mini Draco AK-47 pistol, Yugo Krebs Krink postol; All AR-15 types including the following: American Spirit AR-15 pistol, Bushmaster Carbon 15 pistol, Rock River Arms LAR 15 pistol; Calico Liberty pistols; DSA SA58 PKP FAL pistol; Encom MP5 and MP-45; Heckler and Kock model SP-89 pistol; The following MAC types: MAC-10, MAC-11; Masterpiece Arms MPA A930 mini pistol, MPA460 pistol, MPA Tactical Pistol, and Mini Tactical Pistol; Military Armament Corp. Ingram M-11, Velocity Arms VMAC; Sig Sauer p556 pistol; Sites Spectre; All thomspon types including the following: Thompson TA510D, Thompson TA5; All UZI types including Micro-UZI
Franchi LAW-12 and SPAS 12; All IZHMASH Saiga 12 types, including the following: IZHMASH saiga 12, IZHMASH saiga 12S, IZHMASH saiga 12S EXP-01, IZHMASH saiga12K, IZHMASH saiga12K-030, IZHMASH saiga 12K-040 Taktika; Streetsweeper; Striker 12