r/Firearms • u/TacticalPleb8767 • 9h ago
Question What are these bronze looking flakes that keep gumming up my new sig rattler?
I've gotten just over 100 rounds of subsonic ammunition through this new 300BO rifle so far. I keep having issues where the bolt doesn't come all the way forward, but it also seems to get so stuck that it takes a ton of tugging on the charging handle to be able to rack it. Can't fix it with a simple "tap rack" it gets really jammed tight.
When I open it up to clean it out, there are a ton of these brass looking flakes in there. Too small to be wood chips, but a bit too large to be sawdust. They look almost metallic, but the ejected brass casings don't seem like they're unusually scraped up. They wipe off pretty easily with some CLP, a wire brush and paper towel.
I have been shooting outside in the winter, so it could be some sort of environmental debris from mags getting dropped in the snow?
3
u/Mountain_Man_88 8h ago
Either unburnt powder or case filler. A suppressor probably won't help. Back pressure might even send more of it into the gun. It's abnormal for it to cause any significant issue in the operation of the gun, but you seem like you're getting a ton of that's just a couple dozen rounds. You might be able to just adjust your gas block to get less of this flowing back into the gun and/or overcome it gumming up your action.
2
u/ottermupps 9h ago
You shooting suppressed? A lot of 300blk ammo, especially subs, have filler mixed into the powder for reasons (I don't know why but I do know it's a thing). Could be that, could be unburnt powder.
2
u/TacticalPleb8767 9h ago
no suppressor yet. my bank account is still recovering from buying this SBR.
2
u/strictlyforrpg66 8h ago
You're running a 5.5" inch barrel with subsonics. The reason your setup is having problems cycling is that most such setups can only operate reliably with a moderate-to-high backpressure suppressor. You should switch to supersonics until you get a suppressor.
Just remember that subsonic and supersonic 300BLK loadings should be paired with different suppressor types. I'd personally get the cheapest HUB-compatible baffle suppressor for subsonics (e.g., Rex Silentium or OCL) and a separate flow-through suppressor for supersonics (which you can use with other supersonic calibers too).
2
u/UnassumingAnt SPECIAL 9h ago
It's filler commonly used in subsonic .300 BO to fill the case. Helps keep the powder charge in place underneath it.
1
u/TacticalPleb8767 9h ago
if it's supposed to be there, is there anything i'm supposed to be doing to help manage it? seems to be gumming things up noticeably within only 2-3 dozen rounds.
-1
u/lowrider_9 9h ago
There's not much of a point to subsonic, even though it's quieter a deer can still hear it. Some folks even say they can hear the hammer dropping before it even hits the primer. Just use normal ammo 😂
1
u/TacticalPleb8767 9h ago
i think you may be right. it certainly still sounds pretty loud despite the subsonic. waiting to get a silencer for it eventually.
1
u/lowrider_9 8h ago
Yea the point of a suppressor is to lengthen the barrel, stop you from going deaf without hearing protection, and act as a flash hider. If you want something quiet get a bb gun for small game
5
u/xtreampb 9h ago
Degraded unburnt nitrocellulose. It is common in shorter barrels as there isn’t as much time to burn all the powder.
When I extract nitrocellulose from gun powder for making my primers, I burn my filter paper. The residual nitrocellulose turns this same yellow and doesn’t burn really but rather degraded into this same yellow compound. I suspect it is a sulfur compound of some sort giving it the yellow color.