so I've had my shrike upper for a couple of years now, it had always run pretty good, but this last time I had it out it kept stovepiping at the end of the belt, would burn straight through 180 someodd rounds then stovepipe. long or short belts as soon as it gets to around the 10 to 20 rounds left on the belt it'll act up... using good xm193 federal ammo, as well as ppu m855  both ran fine in the past... I'm thinking the ROF is jumping as it has less belt to pull and somehow causing these stovepipes.

oddly they arent the normal stovepipes either, the head of the case is inside the ejection port and the open end of the casing is pointed out. kinda hard to explain, but has anyone had any experiance with stovepipes with their shrike?  I'm running the mainspring from the factory with an H2 buffer on the 2nd gas port...

I'm thinking if its ROF related to go with an MGI buffer... any thoughts?

Never had any stovepipes in mine.  Sounds like maybe the extractor and or ejector spring is getting worn out.  Those would be the first two things I would replace.  

I have an MGI buffer in my Shrike.  I am not super happy with it as the nested spring inside the buffer (between the weights) disintegrated in about 1000 rounds, the weights locked up inside the body and I got bad bolt bounce and light primer strikes.  I replaced the demolished factory spring with some strong springs but I overall just think the design is just bad.  I just don't see how the small spring in there would ever hold up to be repeatedly crushed between tungsten weights.  I have about 500rds on the buffer with the new springs I put in that are alittle more stout vs. the factory springs.

I am considering trying one of the new hydraulic buffers just to see how it performs.  At $100 its not a huge financial gamble although I have read plenty of horror stories on those as well.

I understand you've had good luck with two types of ammo, but maybe the gas adjustment needs to be set on the third position. My set up is a Colt M-16A1 H-2 buffer Ares recoil spring, 855 ammo and the gas setting is all the way open. Links and casings drop just outside the receiver, sometimes near/on my elbow.

I might also replace the extractor spring as well.

It could be over-gassed. I'd try adjusting the gas regulator or use a heavier buffer.

I would also inspect the extractor, ejector and their springs. I would so check/replace the buffer and piston springs.

my extractor spring seems to be very stiff still, the ejector though, how hard should it be to push the ejector down? its seems to take less pressure to push down than my normal 556 bolts. anyone know if the ejector spring on the shrike is proprietary? or will a normal ar ejector spring work