Model 1 sales upper owners

[medic08]

Here is my question. Will a Model 1 sales upper reliably work with subsonics? I really want to get into a 300 whisper but getting a barrel is looking like it will be way too expensive to have one made by someone else. So what is the word? Unless someone else knows of a place to get a barrel at a decent price. Someone give me some ideas if you can. Thanks.