I want a MK25 as a suppressor host, and wanna buy the factory threaded barrel. Will this require ANY fitting?

The disclaimer says "may require fitting", on the Sig website. I don't wanna mess with it, if I gotta take the thing to a 'smith to get fitted.

Anyone had any issues dropping the factory threaded barrel in a gun that didn't come with it??

The barrel that I put in my MK25 dropped right in.  The threaded barrel that I got for my 1911R needed to be fitted.

Drop in barrels for Glock, Lone Wolf dropped right in. Sig Sauer 226, Sig threaded barrel also dropped in. All 1911 barrels require minor fitting. Minor fitting = send it to a gunsmith.

Thanks for the input ya'll. I actually got lucky yesterday, and found a MK25 TB.........

It just so happens, when I was calling around looking for a factory threaded P226 barrel, the guy was like, "nah, I ain't got any, but since you're looking for a MK25 to buy, I have one with a factory threaded barrel in stock, brand new".

She's quiet as hell with 147gr subsonic, and my Osprey 45.

1010141517 by The One and Only "B"!, on Flickr

Well, just to answer the OP's question, SIG factory barrels may require fitting.

I bought two factory 226 threaded barrels. With the first barrel installed, you could not pull the slide back. With the second barrel in the same gun, you could barely pull it back. Stripped it back down and noticed drag marks on the top of the locking block. So that is where SIG barrels need fitting.

I took a dremel and just took minimal amounts off of the bottom flat of the feed ramp until the movement was smooth. The other barrel was sold to a friend and it simply dropped into his 226 with no problems. So it just depends.

I bought (mail order) a factory Sig P226 threaded barrel that would not fit any of my (3) P226s. The problem was determined to be that the diameter was larger than the original barrels and Sig agreed to exchange it for a new one. In the meantime, I bought the very last Storm Lake threaded barrel from Midway (tried without success to buy 2). That barrel fit all 3 P226s very well with no play and smooth functioning. The replacement barrel that Sig sent wouldn't fit any of my guns, but the diameter was correct. It was sold on the EE with full disclaimer.

When it was time to get a threaded barrel for my P220, I drove out to the pro shop at Sig Academy. The first barrel that they tried in the gun fit well. It seemed like he was prepared to try a bunch of them to find one that fit though.

A Bar-Sto "semi fit" threaded conversion barrel fit my P229 perfectly without modification.

The Sig threaded barrel I picked up for my 220 slipped right in with zero issues.

I dropped a MK25 threaded barrel into my MK25 (when I bought it I never thought I'd be getting into NFA items...) with no problems at all.