I have been doing research on 9mm carbines legal in Maryland. This is not legal advice, this is my own person research. Verify your firearms are legal yourself. I have decided to purchase a ATI AR 9mm Carbine. I picked one up for about $730. It uses Glock mags. As I get more information I will update this. There is also a trigger upgrade for the Keltec, but haven't figured out the price yet. I wrote Masterpiece to ask if they can build one with a collapsible stock, which would make it legal, but haven't heard back an answer. The guy from JP is in the process of getting approval for a compliant GMR-13. If anyone has further information, I will update here. Costs are estimated and rounded.
Cody
Mfr Model WEIGHT Length Stock Mags Barrel System MD Legal Cost Upgrades Beretta CX4 5.67lbs 29.7 Fixed/Inserts Beretta 10-15 16.6 Blowback Yes 750 Trigger/Spring Sig MPX 7.6lbs 33 Collapsable Lancer 30 16 Gas Yes 1600 Not necessary CZ Scorpion EVO 3 S1 7lbs 34.75 Folding CZ 20 16.25 Blowback Yes 950 Kriss Vector Carbine 7.8lbs 39 Collapsable Glock 17 16 Blowback Yes 1300 Just Right Carbine 6.5lbs 33 Collapsable Glock 17 17 Blowback Yes High Point 995-TS 6.25lbs 31 Folding Hipoint 10 rnd 16.5 Blowback Yes 300 American Tactical AT-15 9mm 6.25 36 Collapsable Glock 16 Blowback Yes 800 Keltec Sub 2000 4.25lbs 30 Collapsable Glock, more 16.25 Blowback Yes Olympic Arms K9-GL 6.86lbs 31 Collapsable Glock 16 Gas Likely 950 Rock River ARms LAR 9 7.1lbs 36 Collapsable ? 16 Gas Yes 1235 Masterpiece Arms MPA9300DMG 16.1 Not Likely JP GMR-13 Blowback Certain Config 1160 IWI Tavor B17-9 7.9lbs 26 Fixed/Inserts Colt Style 17 Blowback No-Too Short 1750 Tavor 9mm Conversion 7.9lbs N/A N/A Colt Style N/A Blowback DEPENDS CZ Scorpion EVO 3 Not allowed in IDPA as PCC gun Legal Kriss Vector SBR Not allowed in IDPA as PCC gun