SUB2K .40 Cal Crew


Wondering how many of us are running the .40 version?

If it makes sense, would you like to see a dedicated subcategory to this version? Exchange info, tips / tricks, etc. that may be unique to this caliber?

Not looking to be divisive towards our 9mm brethren, just trying to be a good steward / polite forum member in helping bucketize (IT Term, sorry!) these types of threads. Thoughts? Thanks in advance!


I love my .40 sub. No complaints. I would like to shoot it directly against a 9mm to see the real difference as the only thread I saw on this was the .40 really knocked the steel targets down a lot harder. I don’t plan on suppressing it, otherwise I would have gone with the 9


I also have the 40cal Glock version and I’m very pleased with it. Haven’t had any problem whatsoever. Have done a few Mcarbo upgrades but so far I have just done the real simple ones. Buffer, recoiless charging handle and also the bolt cover. I do however have the pro trigger bundle with the new flat trigger and the cnc trigger guard and of course all the springs and the hardened dowels and the better screws. Also purchased the stainless feed ramp and the polishing kit and I also bought me a dremel into tool to help polish the feed ramp. Would really love to have a new muzzle break for my Sub. Have been shopping for them but I was waiting to see what Mcarbo’s break looks like and I’m sure like every thing else the price will be very reasonable. Also love my Black Mcarbo t-shirt with the skull on it. Get lots of complements on it as well. Anyway I think you guys do great work and delivery time is quick and you stand behind your products. So please consider me for one of your muzzle breaks. I would be FOREVER grateful. Thanks very much. Todd P Kingsport, TN


Dave here in Colo. Compete in Steel Challenge & IDPA w M&P Pro 40. So it made sense to order the Gen 2 Sub2K to fit the same mags! Original reasons were the mags & folding feature.
Was I surprised when after adding some MCarbo mods…it shot awesome!! PCC div has been a ball!!
Added a Vortex Strikefire II Red Dot.
40 costs more to shoot than 9…but little issue since it matches my belt full of mags!!


I own a Glock 35 (full size frame) .40 S&W Gen. 3 so it only made sense to purchase the .40 Sub2K and I got it in the Nickel Boron finish which looks sweet. I have done every MCARBO upgrade for the Sub2K and each upgrade just made it look nicer and made it better to shoot. I have also installed the original Lone Wolf .40 compensator (LWD-COMP) which looks very close to the one MCARBO has coming out. I installed a Fab Defense FGG-S vertical folding forgrip (very compact). As far as an optic I use a Vortex Sparc AR red dot on a quick detach picatinny mount which comes already elevated to clear the front sight. I can pop it on and off quickly for iron sight use and storage if need be.


Looking forward to trying a .40 caliber S2K…has anyone shot both? How much more recoil does the .40 version have? I’ve never shot a .40 cal anything.


I have shot only the the .40 not the nine. It does have a kick to it. It is a short throw on cycling compared to a rifle cartridge. I sit out a recoil pad in and out if the tube for a smoother shooting day

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I also have the Nickle Boron optioned S2K in .40 cal. with G23 mags. Primary reason for going with the .40 is that I have a CZ Scorpion SBR in 9mm and wanted a completely different shooting experience.


I have one a gen 2 40 cal Nickel Byron.

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She just made it to Keltec yesterday for barrel replacement hopefully will have her back soon
… So far only put 200 rounds through it & loved every minute of it


I have the .40, I haven’t shot the 9. I put the recoil buffer, a heavy bolt, the double finger charging handle (not tons of extra weight compared to stock but a little) and a recoil pad on the butt stock. It has cycled great with all of that so far and has really reduced the felt recoil. I’m concerned if I add the recoilless handle it might start getting to be too much and could have cycling issues- I will try it if mcarbo makes a two finger recoilless handle as it’s too comfy to so back to a short stubby handle. I’m really excited for the little bit extra that the brake will provide, especially with reducing flip. Overall it hardly has much flip now, and very light on the recoil for me. I am reducing it as much as possible to make it more desirable for wife and kids who don’t share same enthusiasm yet for shooting so anything is appreciated. I wanted something different from all my .22s


I have the recoiless handle and love it. Even though it is still short the larger diameter makes up for that. It is very comfy to pull back and I could not stand the stock skinny one.


Hey brother, you may want to repost here:

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Would you be willing to post a few pics? Would greatly appreciate to see your sweet setup!


Looks like you have 200 more rounds there! =)

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Curious, where did you find a heavy bolt? I also did the double finger charging handle, really appreciate the extra grip! Recoil Pad was a nice ‘comfort feature’ as the original tore into my lousy excuse for a shoulder pocket… Thanks in advance for the 411!


@dherrle Found the Heavy Bolt! KeltTec Accessories… DOH!


So I just saw this. The heavy bolt when I weighed the difference from the stock was only an extra ~28 grams, it is I believe to be brass so in theory softer to cushion a little, but overall you gain a larger amount weight difference with a sumo or recoilless handle


@dherrle Appreciate the prompt and informative reply!


I have the Gen 1 Sub in .40 with Glock mags. I Love the guns accuracy. It ran fine at first, then found FTF problems. The mag would feed the cartridge, but would get hung up entering the chamber and dent the side of the case. It also pushes the bullet back into the cartridge. Could shoot 1/2 a magazine, then failure to fire would occur. Hopefully replacing the feed ramp with an MCARBO Feed Ramp will do the trick. Also doing Trigger kit, Mag release and screw kit.

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