I've always liked the concept of a pistol caliber carbine ever since someone told me about the Ruger .44 Magnum Carbine. At the time, I just acquired a beautiful used Smith and Wesson 629 .44 Magnum revolver, but Ruger had discontinued the .44 Magnum carbine by the time I learned that it existed. This was all back in the early 1990's before on-line auction sites and the ready access to discontinued firearms we all enjoy today. I prowled a few gun shows hoping to spot one for sale, but I never found one. The appreciation for the idea remained strong, but I gave up on the active pursuit.
After purchasing a Kel-Tec P-32, I started hanging around the KTOG Forum and learned about the SUB-2000 9mm carbine. My pistol caliber carbine interest was fueled again. Since I owned a Glock 17, it was logical that I should buy the Glock 9mm pattern SUB-2000 so I could use the Glock 17 magazines in the SUB-2000 Carbine. I had no problem tracking down the carbine at a local dealer.
I have thoroughly enjoyed the SUB-2000 ownership experience since adding it to the collection. It's been 100% reliable and reasonably accurate out to 50 yards. Much more accurate than if I tried shooting the Glock 17 at that distance. Some guns are just fun to shoot and the SUB-2000 is one of those fun guns you can look forward to getting out on the range.
Like most guns, there are always customizations and add-ons that can make your SUB-2000 uniquely yours. I've seen SUB-2000s with insane $1000 plus customization packages applied to them. I've always wanted to customize mine, but only to change out a few basic parts that would enhance my overall shooting experience with the carbine. I really like that the SUB-2000 is compact, light, and folds for storage so my modification list doesn't impact any of those features. I consider this level of modification to be low impact and easily changed back to the factory configuration if I want to do that in the future.
TANDEMKROSS offers a package of 4 upgrade components for the SUB-2000. They offer each component individually, or as a combo package. I've always appreciated the detailed color installation instructions that come with every TANDEMKROSS product. They also have several YouTube installation videos available. They make it easy to be successful installing their upgrades.
The TANDEMKROSS upgrade package focuses on replacing the plastic Kel-Tec sight components with metal replacement parts. They also add some unique features with their parts that Kel-Tec doesn't offer.
The most unique item in the package is the Eagle Eye rear sight. For the folks running top rail optics, having the ability to fold down the rear sight could be a tremendous benefit. I like the sight because it eliminates the peep sight and replaces it with a notched rear sight. At 50 yards or less, I prefer this type of sight.
If you spend enough time on the Kel-Tec forum you will see complaints about the factory front sight cracking/breaking/failing. The TANDEMKROSS front sight replacement should eliminate those problems while still providing a high-visibility fiber optic insert. The fiber optic is easily replaceable if it should be damaged.
Kel-Tec also offers accessories for the SUB-2000. From their list of available accessories, I liked the Dust Cover and Stock Extension. The Dust Cover minimizes the chance of something getting into the barrel when the carbine is folded and the Stock Extension adds about 1.5 inches to the length of pull. Perhaps I'll try the Sub Picatinny Rail and Spare Magazine Holder if I decide to make more invasive modifications in the future.
With a folded length of about 16.5", the SUB-2000 is too large for most pistol cases and too small to justify a compact rifle case. With some searching, I found the REX Scoped Handgun Case from Soft Armor. This case is a bit larger than it needs to be, but it will hold both the SUB-2000 carbine and Glock 17 pistol along with a boatload of magazines.
The total package price for all the modifications and case was less than $150.00 if you include shipping costs. That may seem like quite a bit to add to a rifle that sells for under $350 in normal market conditions. For me it was easy to justify the cost because it will make my SUB-2000 more fun, and hopefully accurate, for many years to come.
The video describes the upgrades in more detail. I did the actual installations off camera in the interest of keeping it short. All the parts installations went smoothly and were really easy to do without using any specialized tools.
If you asked me for additional ideas to improve the SUB-2000, I would immediately ask for a Glock 21 SUB-2000 in .45 Auto. Since Kel-Tec only makes the SUB-2000 in 9mm and .40 S&W, a .45 Auto version may not be possible. If they ever decide to produce one in the future, please add my name to the top of the waiting list.