Malfunction today...your thoughts on a fix?

[TomMcC]

Another possibility. Both the extractor and the ejector can be fine. If the bcg travels back but does not travel far enough for the case mouth to clear the receiver enough to be pushed out the port, when the bcg starts its forward motion the empty is pushed back into the chamber causing the appearance it was never extracted. As the bcg goes forward, since it did not go back far enough to catch the head of the next cartridge it rides up over the next cartridge, dragging it forward until it pushed up by the feed ramps. The bcg will then lodge on the case causing a dent in the case just before the shoulder. Usually this will not result in the bullet being set back.

If the bcg did go back far enough that it does catch the case properly and push it out of the magazine without the fired case having been fully extracted the bullet will probably be pushed into the barrel extension below the feed ramps and will be pushed back into the case mouth.

As described in the OP I would bet on a short stroke. Check the gas system for fouling and the carrier key for signs of leakage. Then a through cleaning.

From the OP brief description, I don't think it's short stroking. The empty is only being extracted 1/2", that's not even a 1/3 of the length of the case, yet the bolt isn't in contact with case any longer. The bolt has released the case and continued back to, and if I understand him correctly, pick up another case and wedge it between the bolt face and the feed ramps. 1/2" is a mighty short, short stroke. On top of that the OP said that an extractor donut pretty much has fix it.

[sva01]

From the OP brief description, I don't think it's short stroking. The empty is only being extracted 1/2", that's not even a 1/3 of the length of the case, yet the bolt isn't in contact with case any longer. The bolt has released the case and continued back to, and if I understand him correctly, pick up another case and wedge it between the bolt face and the feed ramps. 1/2" is a mighty short, short stroke. On top of that the OP said that an extractor donut pretty much has fix it.

Quoted for truth

[matemike]

I was getting fte’s on a 300 BO that was remedied by a $1 extractor spring donut. Since then I stocked on springs and donuts as well as the rubber barrels that some guys put inside the extractor spring.

I’d be interested to see if that steel cased ammo was expanding beyond chamber specs causing it to want to stick in the chamber after being fired. But to truly do that you would need for another round to NOT be forced into the spent stuck case.

Do they feed easily into the chamber? No forcing if easing the bolt into battery?

[TomMcC]

I was getting fte’s on a 300 BO that was remedied by a $1 extractor spring donut. Since then I stocked on springs and donuts as well as the rubber barrels that some guys put inside the extractor spring.

I’d be interested to see if that steel cased ammo was expanding beyond chamber specs causing it to want to stick in the chamber after being fired. But to truly do that you would need for another round to NOT be forced into the spent stuck case.

Do they feed easily into the chamber? No forcing if easing the bolt into battery?

It's my general understanding is that steel cases do not expand as well as brass cases. Thus...the steel case doesn't seal the chamber as well as the more expandable brass case. This lack of efficient sealing allows burning powder blow by in the chamber. Dirtier chamber leads to harder extraction.

[Dr. Bullseye]

OP, you have an incredible number of modifications and all of them would seem to influence the cycling of the rifle.

Rifle is a BCM 11.5" carbine upper with fixed FSB. LMT enhanced carrier with a BCM OEM bolt, A5H4 buffer, and Sprinco green buffer spring. Shooting suppressed with a Silencer Co. Omega 300 with Wolf steel case ammo in a Gen 2 windowed PMAG

I am no expert here and I have had cycling troubles in the past myself. But make one change at a time and then test fire before moving on to another change.

[HKGuns]

In agreement with Dr. Bullseye. You've made a number of changes that can affect gas and cycling. I'd take it back to as it came from the factory and work from there.

[sva01]

@HkGuns and Dr. Bullseye, the issue was fixed with a simple extractor spring donut.

I will be replacing the actual extractor spring once parts arrive as it has likely weakened as TomMcC mentioned.

[Clint]

Over gassing can increase extractor slippage.

In a scenario like this, it may run fine without the suppressor, but have extraction issues with the suppressor due to the increased gas drive.

Increased extractor spring tension usually resolves things.

[Dr. Bullseye]

@HkGuns and Dr. Bullseye, the issue was fixed with a simple extractor spring donut.

I will be replacing the actual extractor spring once parts arrive as it has likely weakened as TomMcC mentioned.

That's great!!!