Email their chiefs of staff directly
Sorry about the formatting - make sure you cut and paste the entire email address...
Official: Sen. Mark Begich (D-AK)
Title: Chief of Staff
Email: david_ramseur@begich.senate.gov
Phone: (202) 224-3004
Fax: (202) 224-2354
Official: Sen. Lisa Murkowski (R-AK)
Title: Chief of Staff
Email: edward_hild@murkowski.senate.gov
Phone: (202) 224-6665
Fax: (202) 224-5301
Official: Sen. Jeff Sessions (R-AL)
Title: Chief of Staff
Email: rick_dearborn@sessions.senate.gov
Phone: (202) 224-4124
Fax: (202) 224-3149
Official: Sen. Richard C. Shelby (R-AL)
Title: Chief of Staff
Email: alan_hanson@shelby.senate.gov
Phone: (202) 224-5744
Fax: (202) 224-3416
Official: Sen. Mark Pryor (D-AR)
Title: Chief of Staff
Email: andy_york@pryor.senate.gov
Phone: (202) 224-2353
Fax: (202) 228-0908
Official: Sen. John Boozman (R-AR)
Title: Chief of Staff
Email: Matt_Sagely@boozman.senate.gov
Phone: (202) 224-4843
Fax: (202) 228-1371
Official: Sen. Jeff Flake (R-AZ)
Title: Chief of Staff
Email: steve_voeller@flake.senate.gov
Phone: (202) 224-4521
Fax: (202) 228-0515
Official: Sen. John McCain (R-AZ)
Title: Chief of Staff
Email: pablo_carrillo@mccain.senate.gov
Phone: (202) 224-2235
Fax: (202) 228-2862
Official: Sen. Dianne Feinstein (D-CA)
Title: Chief of Staff
Email: chris_thompson@feinstein.senate.gov
Phone: (202) 224-3841
Fax: (202) 228-3954
Official: Sen. Barbara Boxer (D-CA)
Title: Chief of Staff
Email: laura_schiller@boxer.senate.gov
Phone: (202) 224-3553
Fax: (202) 224-0454
Official: Sen. Mark Udall (D-CO)
Title: Chief of Staff
Email: michael_sozan@markudall.senate.gov
Phone: (202) 224-5941
Fax: (202) 224-6471
Official: Sen. Michael Bennet (D-CO)
Title: Chief of Staff
Email: jonathan_davidson@bennet.senate.gov
Phone: (202) 224-5852
Fax: (202) 228-5036
Official: Sen. Christopher S. Murphy (D-CT)
Title: Chief of Staff
Email: francis_creighton@murphy.senate.gov
Phone: (202) 224-4041
Fax: (202) 228-9604
Official: Sen. Richard Blumenthal (D-CT)
Title: Chief of Staff
Email: laurie_rubiner@blumenthal.senate.gov
Phone: (202) 224-2823
Fax: (202) 224-9673
Official: Sen. Thomas R. Carper (D-DE)
Title: Chief of Staff
Email: james_reilly@carper.senate.gov
Phone: (202) 224-2441
Fax: (202) 228-2190
Official: Sen. Chris Coons (D-DE)
Title: Chief of Staff
Email: todd_webster@coons.senate.gov
Phone: (202) 224-5042
Fax: (202) 228-3075
Official: Sen. Bill Nelson (D-FL)
Title: Chief of Staff
Email: pete_mitchell@billnelson.senate.gov
Phone: (202) 224-5274
Fax: (202) 228-2183
Official: Sen. Marco Rubio (R-FL)
Title: Chief of Staff
Email: cesar_conda@rubio.senate.gov
Phone: (202) 224-3041
Fax: (202) 228-0285
Official: Sen. Saxby Chambliss (R-GA)
Title: Chief of Staff
Email: charlie_harman@chambliss.senate.gov
Phone: (202) 224-3521
Fax: (202) 224-0103
Official: Sen. Johnny Isakson (R-GA)
Title: Chief of Staff
Email: chris_carr@isakson.senate.gov
Phone: (202) 224-3643
Fax: (202) 228-0724
Official: Sen. Mazie K. Hirono (D-HI)
Title: Chief of Staff
Email: betsy_lin@hirono.senate.gov
Phone: (202) 224-6361
Fax: (202) 224-2126
Official: Sen. Brian Schatz (D-HI)
Title: Chief of Staff
Email: andrew_winer@schatz.senate.gov
Phone: (202) 224-3934
Fax: (202) 228-1153
Official: Sen. Tom Harkin (D-IA)
Title: Chief of Staff
Email: Brian_Ahlberg@harkin.senate.gov
Phone: (202) 224-3254
Fax: (202) 224-9369
Official: Sen. Charles E. Grassley (R-IA)
Title: Chief of Staff
VACANT
Phone: (202) 224-3744
Fax: (202) 224-6020
Official: Sen. Jim Risch (R-ID)
Title: Chief of Staff
Email: john_sandy@risch.senate.gov
Phone: (202) 224-2752
Fax: (202) 224-2573
Official: Sen. Michael D. Crapo (R-ID)
Title: Chief of Staff
Email: john_hoehne@crapo.senate.gov
Phone: (202) 224-6142
Fax: (202) 228-1375
Official: Sen. Richard J. Durbin (D-IL)
Title: Chief of Staff
Email: pat_souders@durbin.senate.gov
Phone: (202) 224-2152
Fax: (202) 228-0400
Official: Sen. Mark S. Kirk (R-IL)
Title: Chief of Staff
Email: kate_dickens@kirk.senate.gov
Phone: (202) 224-2854
Fax: (202) 228-4611
Official: Sen. Joe Donnelly (D-IN)
Title: Chief of Staff
Email: joel_elliott@donnelly.senate.gov
Phone: (202) 224-4814
Fax: (202) 224-5011
Official: Sen. Dan Coats (R-IN)
Title: Chief of Staff
Email: dean_hingson@coats.senate.gov
Phone: (202) 224-5623
Fax: (202) 228-1820
Official: Sen. Pat Roberts (R-KS)
Title: Chief of Staff
Email: Jackie_Cottrell@roberts.senate.gov
Phone: (202) 224-4774
Fax: (202) 224-3514
Official: Sen. Jerry Moran (R-KS)
Title: Chief of Staff
Email: todd_novascone@moran.senate.gov
Phone: (202) 224-6521
Fax: (202) 228-6966
Official: Sen. Mitch McConnell (R-KY)
Title: Chief of Staff
Email: josh_holmes@mcconnell.senate.gov
Phone: (202) 224-2541
Fax: (202) 224-2499
Official: Sen. Rand Paul (R-KY)
Title: Chief of Staff
Email: william_henderson@paul.senate.gov
Phone: (202) 224-4343
Official: Sen. Mary L. Landrieu (D-LA)
Title: Chief of Staff
Email: donald_cravins@landrieu.senate.gov
Phone: (202) 224-5824
Fax: (202) 224-9735
Official: Sen. David Vitter (R-LA)
Title: Chief of Staff
Email: kyle_ruckert@vitter.senate.gov
Phone: (202) 224-4623
Fax: (202) 228-5061
Official: Sen. Elizabeth Warren (D-MA)
Title: Chief of Staff
Email: mindy_myers@warren.senate.gov
Phone: (202) 224-4543
Fax: (202) 228-2071
Official: Sen. William Cowan (D-MA)
Title: Senior Advisor
Email: val_young@cowan.senate.gov
Phone: (202) 224-2742
Fax: (202) 224-8525
Official: Sen. Benjamin L. Cardin (D-MD)
Title: Chief of Staff
Email: chris_lynch@cardin.senate.gov
Phone: (202) 224-4524
Fax: (202) 224-1651
Official: Sen. Barbara A. Mikulski (D-MD)
Title: Chief of Staff
Email: Julia_Frifield@mikulski.senate.gov
Phone: (202) 224-4654
Fax: (202) 224-8858
Official: Sen. Angus King Jr.(I-ME)
Title: Chief of Staff
Email: kay_rand@king.senate.gov
Phone: (202) 224-3825
Fax: (202) 224-1946
Official: Sen. Susan Collins (R-ME)
Title: Chief of Staff
Email: mary_dietrich@collins.senate.gov
Phone: (202) 224-2523
Fax: (202) 224-2693
Official: Sen. Debbie Stabenow (D-MI)
Title: Chief of Staff
Email: dan_farough@stabenow.senate.gov
Phone: (202) 224-4822
Fax: (202) 228-0325
Official: Sen. Carl Levin (D-MI)
Title: Chief of Staff
Email: david_lyles@levin.senate.gov
Phone: (202) 224-6221
Fax: (202) 224-1388
Official: Sen. Amy Klobuchar (D-MN)
Title: Chief of Staff
Email: rose_baumann@klobuchar.senate.gov
Phone: (202) 224-3244
Fax: (202) 228-2186
Official: Sen. Al Franken (D-MN)
Title: Chief of Staff
Email: casey@franken.senate.gov
Phone: (202) 224-5641
Fax: (202) 224-0044
Official: Sen. Claire McCaskill (D-MO)
Title: Chief of Staff
Email: julie_dwyer@mccaskill.senate.gov
Phone: (202) 224-6154
Fax: (202) 228-6326
Official: Sen. Roy Blunt (R-MO)
Title: Chief of Staff
Email: glen_chambers@blunt.senate.gov
Phone: (202) 224-5721
Fax: (202) 224-8149
Official: Sen. Roger Wicker (R-MS)
Title: Chief of Staff
Email: michelle_richardson@wicker.senate.gov
Phone: (202) 224-6253
Fax: (202) 228-0378
Official: Sen. Thad Cochran (R-MS)
Title: Chief of Staff
Email: bruce_evans@cochran.senate.gov
Phone: (202) 224-5054
Fax: (202) 224-9450
Official: Sen. Jon Tester (D-MT)
Title: Chief of Staff
Email: tom_lopach@tester.senate.gov
Phone: (202) 224-2644
Fax: (202) 224-8594
Official: Sen. Max Baucus (D-MT)
Title: Chief of Staff
Email: paul_wilkins@baucus.senate.gov
Phone: (202) 224-2651
Fax: (202) 224-9412
Official: Sen. Kay Hagan (D-NC)
Title: Chief of Staff
Email: mike_harney@hagan.senate.gov
Phone: (202) 224-6342
Fax: (202) 228-2563
Official: Sen. Richard M. Burr (R-NC)
Title: Chief of Staff
Email: chris_joyner@burr.senate.gov
Phone: (202) 224-3154
Fax: (202) 228-2981
Official: Sen. Heidi Heitkamp (D-ND)
Title: Chief of Staff
Email: tessa_gould@heitkamp.senate.gov
Phone: (202) 224-2043
Fax: (202) 224-7776
Official: Sen. John Hoeven (R-ND)
Title: Chief of Staff
Email: don_larson@hoeven.senate.gov
Phone: (202) 224-2551
Fax: (202) 224-7999
Official: Sen. Deb Fischer (R-NE)
Title: Chief of Staff
Email: mike_hybl@fischer.senate.gov
Phone: (202) 224-6551
Fax: (202) 228-1325
Official: Sen. Mike Johanns (R-NE)
Title: Chief of Staff
Email: terri_moore@johanns.senate.gov
Phone: (202) 224-4224
Fax: (202) 228-0436
Official: Sen. Jeanne Shaheen (D-NH)
Title: Chief of Staff
Email: maura_keefe@shaheen.senate.gov
Phone: (202) 224-2841
Fax: (202) 228-3194
Official: Sen. Kelly Ayotte (R-NH)
Title: Chief of Staff
Email: john_easton@ayotte.senate.gov
Phone: (202) 224-3324
Fax: (202) 224-4952
Official: Sen. Robert Menendez (D-NJ)
Title: Chief of Staff
Email: daniel_o’brien@menendez.senate.gov
Phone: (202) 224-4744
Fax: (202) 228-2197
Official: Sen. Jeff Chiesa (R-NJ)
Title: Chief of Staff
Email: donna_mullins@chiesa.senate.gov
Phone: (202) 224-3224
Fax: (202) 228-4054
Official: Sen. Martin Heinrich (D-NM)
Title: Chief of Staff
Email: steve_haro@heinrich.senate.gov
Phone: (202) 224-5521
Fax: (202) 228-2841
Official: Sen. Tom Udall (D-NM)
Title: Chief of Staff
Email: michael_collins@tomudall.senate.gov
Phone: (202) 224-6621
Fax: (202) 228-3261
Official: Sen. Dean Heller (R-NV)
Title: Chief of Staff
Email: mac_abrams@heller.senate.gov
Phone: (202) 224-6244
Fax: (202) 228-6753
Official: Sen. Harry Reid (D-NV)
Title: Chief of Staff
Email: david_krone@reid.senate.gov
Phone: (202) 224-3542
Fax: (202) 224-7327
Official: Sen. Kirsten Gillibrand (D-NY)
Title: Chief of Staff
Email: jess_fassler@gillibrand.senate.gov
Phone: (202) 224-4451
Fax: (202) 228-0282
Official: Sen. Charles E. Schumer (D-NY)
Title: Chief of Staff
Email: mike_lynch@schumer.senate.gov
Phone: (202) 224-6542
Fax: (202) 228-3027
Official: Sen. Sherrod Brown (D-OH)
Title: Chief of Staff
Email: mark_powden@brown.senate.gov
Phone: (202) 224-2315
Fax: (202) 228-6321
Official: Sen. Rob Portman (R-OH)
Title: Chief of Staff
Email: rob_lehman@portman.senate.gov
Phone: (202) 224-3353
Fax: (202) 224-9075
Official: Sen. James M. Inhofe (R-OK)
Title: Chief of Staff
Email: ryan_jackson@inhofe.senate.gov
Phone: (202) 224-4721
Fax: (202) 228-0380
Official: Sen. Tom Coburn (R-OK)
Title: Chief of Staff
Email: brian_treat@coburn.senate.gov
Phone: (202) 224-5754
Fax: (202) 224-6008
Official: Sen. Jeff Merkley (D-OR)
Title: Chief of Staff
Email: michael_zamore@merkley.senate.gov
Phone: (202) 224-3753
Fax: (202) 228-3997
Official: Sen. Ron Wyden (D-OR)
Title: Chief of Staff
Email: jeff_michels@wyden.senate.gov
Phone: (202) 224-5244
Fax: (202) 228-2717
Official: Sen. Bob Casey (D-PA)
Title: Chief of Staff
Email: James_Brown@Casey.senate.gov
Phone: (202) 224-6324
Fax: (202) 228-0604
Official: Sen. Patrick J. Toomey (R-PA)
Title: Chief of Staff
Email: christopher_gahan@toomey.senate.gov
Phone: (202) 224-4254
Fax: (202) 228-0284
Official: Sen. Sheldon Whitehouse (D-RI)
Title: Chief of Staff
Email: sam_goodstein@whitehouse.senate.gov
Phone: (202) 224-2921
Fax: (202) 228-6362
Official: Sen. Jack Reed (D-RI)
Title: Chief of Staff
Email: Neil_Campbell@Reed.senate.gov
Phone: (202) 224-4642
Fax: (202) 224-4680
Official: Sen. Lindsey Graham (R-SC)
Title: Chief of Staff
Email: Richard_Perry@lgraham.senate.gov
Phone: (202) 224-5972
Fax: (202) 224-3808
Official: Sen. Tim Scott (R-SC)
Title: Chief of Staff
Email: rich_dunn@scott.senate.gov
Phone: (202) 224-6121
Fax: (202) 228-5143
Official: Sen. Tim Johnson (D-SD)
Title: Chief of Staff
Email: Drey_Samuelson@johnson.senate.gov
Phone: (202) 224-5842
Fax: (202) 228-5765
Official: Sen. John Thune (R-SD)
Title: Chief of Staff
Email: ryan_nelson@thune.senate.gov
Phone: (202) 224-2321
Fax: (202) 228-5429
Official: Sen. Bob Corker (R-TN)
Title: Chief of Staff
Email: todd_womack@corker.senate.gov
Phone: (202) 224-3344
Fax: (202) 228-0566
Official: Sen. Lamar Alexander (R-TN)
Title: Chief of Staff
Email: ryan_loskarn@alexander.senate.gov
Phone: (202) 224-4944
Fax: (202) 228-3398
Official: Sen. Ted Cruz (R-TX)
Title: Chief of Staff
Email: chiproy@cruz.senate.gov
Phone: (202) 224-5922
Official: Sen. Orrin G. Hatch (R-UT)
Title: Chief of Staff
Email: michael_kennedy@hatch.senate.gov
Phone: (202) 224-5251
Fax: (202) 224-6331
Official: Sen. Mike Lee (R-UT)
Title: Chief of Staff
Email: boyd_matheson@lee.senate.gov
Phone: (202) 224-5444
Fax: (202) 228-1168
Official: Sen. Tim Kaine (D-VA)
Title: Chief of Staff
Email: mike_henry@kaine.senate.gov
Phone: (202) 224-4024
Fax: (202) 228-6363
Official: Sen. Mark Warner (D-VA)
Title: Chief of Staff
Email: luke_albee@warner.senate.gov
Phone: (202) 224-2023
Fax: (202) 224-6295
Official: Sen. Bernard Sanders (I-VT)
Title: Chief of Staff
VACANT
Phone: (202) 224-5141
Fax: (202) 228-0776
Official: Sen. Patrick J. Leahy (D-VT)
Title: Chief of Staff
Email: John_Dowd@leahy.senate.gov
Phone: (202) 224-4242
Fax: (202) 224-3479
Official: Sen. Maria Cantwell (D-WA)
Title: Chief of Staff
Email: jennifer_griffith@cantwell.senate.gov
Phone: (202) 224-3441
Fax: (202) 228-0514
Official: Sen. Patty Murray (D-WA)
Title: Chief of Staff
Email: mike_spahn@murray.senate.gov
Phone: (202) 224-2621
Fax: (202) 224-0238
Official: Sen. Tammy Baldwin (D-WI)
Title: Chief of Staff
Email: bill_murat@baldwin.senate.gov
Phone: (202) 224-5653
Fax: (202) 224-9787
Official: Sen. Ron Johnson (R-WI)
Title: Chief of Staff
Email: tony_blando@ronjohnson.senate.gov
Phone: (202) 224-5323
Fax: (202) 228-6965
Official: Sen. Joe Manchin III(D-WV)
Title: Chief of Staff
Email: hayden_rogers@manchin.senate.gov
Phone: (202) 224-3954
Fax: (202) 228-0002
Official: Sen. Jay Rockefeller (D-WV)
Title: Chief of Staff
Email: Kerry_Ates@rockefeller.senate.gov
Phone: (202) 224-6472
Fax: (202) 224-7665
Official: Sen. John Barrasso (R-WY)
Title: Chief of Staff
Email: dan_kunsman@barrasso.senate.gov
Phone: (202) 224-6441
Fax: (202) 224-1724
Official: Sen. Michael B. Enzi (R-WY)
Title: Chief of Staff
Email: Flip_McConnaughey@enzi.senate.gov
Phone: (202) 224-3424
Fax: (202) 228-0359
Additional resources:
http://capwiz.com/gunowners/issues/alert/?alertid=62730346
http://capwiz.com/eagleforum/issues/alert/?alertid=62714421
http://capwiz.com/eagleforum/issues/?style=D
http://capwiz.com/caps/issues/alert/?alertid=62644426
http://www.capwiz.com/fair/home/