So, what the heck is the P221? It's a prototype double-stack .45 caliber SIG that the factory was working on in 2001. Supposed to hold 14 rounds at full capacity, the gun has the milled slide with the profile of the the Legacy P229 (half height rear cocking serrations). I've read that there are two or three of these prototypes still float around. So, why did SIG can the project to bring the gun into full production? One theory is that, since this was right during the Klinton AWB, the mag would have had to be neutered to 10 rounds, thus limiting its appeal. My opinion, however, is that, although neutered, it's still a 10 +1 .45 gun. And, in the AWB era a 10+1 .45 gun would have competed well against the same capacity 9mm guns. And the AWB was approaching its sunset in 3 years. Then the gun would be at full capacity. Moreover, their European market is not hampered by the mag restriction. So, abolishing that project seems to odd to me.

Then, nothing happened until well into the second decade, when they brought the modern version of the P221, the P227, to production. But, by this time, the world has moved on. Too many things worked against it. The 9mm is king. Cheap plastic reigns supreme. Seventeen-, twenty-, thirty-round mags are legal again. The P227 14-round mag, which was a major selling point, never worked properly. So, the gun finally died.

Here are a couple of pics of the P221 I grabbed on the internet. You might say it's a P229 on steroid.

This one is from a thread from The High Road. Supposed to have been sold in Switzerland in 2007.



This one is from another article.

Most of us didn't believe they would ever let the AWB sunset in '04.

Thank God the Republicans were in charge at the time.

Why did Sig ever go with that style of serrations? Those were a pain in the ass on the P229. I still would have bought one since the only other option for a double stack 45 were the USP (awful trigger), Glock 21 (too massive), or an expensive and unreliable 2011.

IIRC, reading of this years back in Sig Forum, this was a all steel gun. 4140 or some industry standard steel but not stainless steel or aluminum.

I do recall reading about this particular SiG late 1999 in a gun rag. SiG at the time was trying to develop the handgun. Would have been a nice shooter in my opinion It loosely reminds me of Para's prototype handgun, although that was a 9mmx19.

If only..... For years I would have paid good money for a double stack Sig .45. When the 227 finally came out, I was right on the edge but, as you mentioned was moving on to other things and never did grab one. Limited to 10 rounds was a bit odd, when the slim 220 held 8 anyway. If the 227 could rock 14 rounds, I'd have two.

I went through Sig Armorer class in August 2001 and we asked about the 221 and the instructor said it was a myth. I would have gladly bought even with 10rd mags. I don’t understand why they didn’t produce it. 45acp and .40 were still in most police holster back then.

I like (and miss) the clean lines of the pistol. Too damn bad every gun, besides the P210, Sig has to slap a rail and optics plate on.

Read a few stories (with no pictures about this one.

The slide and trigger guard have a cleaner look to them.

Who knows, maybe back then they may have considered one in .38 Super.

In 2001 I would have bought two of these, even if I had to sell my car to pay for them.

If Sig had made the 221/227 in 2001 time frame, it’s would have been a decent seller.