Bison Tactical prefits are chambered by Modacam Custom Rifles. It's probably the best prefit out there.
Unfortunately, my experience with Modacam chambering my barrel was not positive.
I purchased my RimX .22 LR through Bison early this year, along with an 18" MTU pre-fit. The pre-fit was chambered by Modacam.
Early on, I was experiencing some ejection issues, and this prompted me to take a closer look at some things (including my chamber). Using my borescope, I immediately noticed very nasty gouging around the circumference of the throat area. This was in stark contrast to the bore, which was nothing short of breathtaking (this is my first Benchmark, and their product is simply amazing; the surfaces are extremely smooth, and the rifling impossibly crisp, and it's really a thing of beauty overall).
I called Fred at Bison (a very nice guy), he got me in touch with Jonathan at Modacam (also a very nice guy - this isn't personal), and, after seeing my borescope video, Jonathan acknowledged the issue and sent me a shipping label for the barrel. After receiving the barrel, he asked me if I'd mind losing a half-inch of barrel as he'd have to set it back to fix things completely. I wasn't thrilled, but I said ok (I'm not out to be difficult). Jonathan was very polite through all of this and it did seem like he really wanted to make things right (I need to give credit where it's due).
When I received the barrel back, though, I was beyond disappointed as soon as I unboxed it.
The flawless matte finish of the exterior had been all banged up. There are lots of little divots/grooves in it, some deep enough to can catch my nail in. There are chatter marks/scoring running length-wise in several spots, too. None of these are symmetrical or seem purposeful, but instead seem to be the result of rough, careless handling.
The shank looks terrible, with an uneven (almost wavy) surface and a groove around its circumference where it looks like a cut was started in the wrong place or something. The factory markings on the barrel are now abbreviated due to the half-inch being cut off (something I didn't think of when I agreed to shortening it).
The new chamber still has a small problem area in the throat, but it's much better than it was originally. It now has several lateral scratches, too, that are unsightly, but I can't see them causing any issues.
I'm really surprised Jonathan was happy with the barrel's condition and would send it back to a customer this way.
Having no faith in Modacam's work, and not wanting to miss upcoming matches, I coated the barrel in Aluma-hyde (to cover the mars), installed the barrel to the action (putting the ugly shank work out of sight), and moved on. I don't at all feel that I got what I paid for, and that beautiful Benchmark barrel certainly didn't receive the treatment it deserved.
I do well at matches, so the barrel shoots good enough. I'll just have to live with it or come up with an additional $800 for a new Benchmark chambered by someone else. However, I thought I might be able to save somebody some heartache by sharing my experience.