Armory Sponsor
Posted: 3/29/2026 4:08:47 PM EDT
|
I have a factory Daniel Defense MK18 SBR circa 2015, so equipped with the larger gas port. Gun runs flawlessly suppressed, but gets dirty to the point of malfunction at around 200-250 rounds. This has happened twice in separate rifle classes, with a freshly cleaned upper and BCG. Gun is gassy for sure, and I notice it more shooting left handed, but it isn’t unbearable. Other than swapping the barrel for a newer, smaller gas port version, I have considered swapping to a H2/H3 buffer. Anything else to try? Other than keeping it wet during shooting. Ammo has been almost exclusively Federal XM193. Cleaned well with Breakfree CLP and lubed generously with Breakfree Synthetic. |
Joined:
Jul 2024
Posts:
70
EE: 0% (0)
WI, USA
|
Are you shooting exclusively suppressed? If so, a BRT gas tube around .059 will tame the excess gas but will turn it into a single shot with the can off. Gov 10.3s should be .070 which is equivalent to a BRT carbine tube with a ~.071-.073 port. https://blackrivertactical.com/WP/BRT-EZTUNE-Gas-Tube-Configurable-Carbine-p103167251 |
|
You can address the oversized gas port with an adjustable gas block, port insert, gastube, or whatever route you want to go. An H3 will offer a minor reduction in carrier speed, but it is a band-aid at best. At one time, DD would swap the .083" or so ported barrels for a proper .070" ported barrel for free. They might still do that, not sure. Might be worth contacting them; they have excellent customer service. That said, you aren't experiencing malfunctions simply because your gun is "dirty" after only 200-250 rounds. Something else is at play. Arguably, the larger port could be more forgiving running dirty, but an oversized port can also cause early unlocking and failure to extract. The chamber pressure isn't given sufficient time to drop before extraction, and as the lubricant burns off or gets fouled, the small amount of added friction isn't allowing it to yank the still swollen brass from the chamber. So, whether it's directly an issue of the oversized port or something else, it depends on what kind of malfunctions you're experiencing. I'd strongly suspect the above scenario. If you don't address the gas port, your best bet, assuming the above, would probably be an H3 and potentially even a stronger spring to try and delay unlocking a bit longer. I'd also recommend a better lubricant and/or reapplying more often. You might be underlubricating to begin with. Personally, I use light grease -- Redline CV2/Mobil 1 synthetic mixed, Superlube grease and Superlube Oil mixed, Cherrybalmz, and so on. Don't use NLGI 2 grease (the most common). You want NLGI 00 or 000 (think ketchup or applesauce consistency). Oil is fine as well, but in my experience, a light grease will go far longer between reapplications compared to oil, and doesn't burn off easily, which is especially important when shooting suppressed. In any case, lubricate liberally and reapply as needed. You should be able to go thousands upon thousands of rounds suppressed without malfunctions, shooting an utterly filthy gun -- simply by reapplying lube.  That's one of my DD .070" barreled CQBR/Mk18 URGs after well over 3,000 rounds suppressed. It was still running just fine; zero malfunctions. Being dirty isn't the issue after so few rounds. |
Practice, the master of all things. - Augustus
IG: @cqbr.kurdt
Looking for: LMT SOPMOD Gen 1
IG: @cqbr.kurdt
Looking for: LMT SOPMOD Gen 1
|
What can? Any non flow through can and just a carbine buffer and spring with that old barrel and that thing is launching your bolt carrier at mock fuck. But yeah I agree its more than the fouling causing your stoppages. I’d start by just putting an H3 in it for sure, I bet you stopping having issues. Ultimately gas tuning is the answer as long as you don’t go overboard and make your gun unreliable |
Armory Sponsor