i had to aquire the H/L regulator for my ACR recently. let me add that i am the first to bust out any company when i get bad service but when i talked with BM on this is was pretty good. despite some phone tag and i got routed to the wrong person. my big issue was i didnt want to send it back in. i just dont like doing it. basically its a bullet launcher with my name on it. anyway i talked to them at noon on a monday and got my regulator the very next day!!! very impressed it came way sooner than expected! now i had to get the H/L regulator cause my ACR started jamming just like the guys on youtube. i couldnt go 20 rounds without a few "stove pipes" and a stove pipe really isnt a stove pipe in the ACR it will double feed on a normal tap and rack. I did go out and try it and it worked just fine but guess what i threw the U/S regulator on and WHAM JAM!! so i throw on the H/L. WHAM WHAM no JAM. my serial number is quite low too. i wonder if this is just happing with a certian lot number of these rifles or if they all could possibly be affected? cause i kinda wanna get another one but im tempted with this whole gas regulator thing because theres a pretty big difference is the U/S and H/L regulator. what has everyone heard or experienced?