I didn't see you comment on gas port size in the barrel.
Many 'Premium' or 'Semi-Finished' barrels are 'Pilot Drilled' and not drilled to full size.
The reason for this is gunsmiths will size gas port for specific ammunition the customer is using.
When laymen get hold of semi finished barrels they might finish chamber it, but miss the gas port sizing.
You say 'Short Stroke', where is the bolt hitting the next round in the mag?
A true 'Short Stroke' won't usually hit the side of the round in the mag, since the bolt doesn't actually move far enough to the rear for next round to pop up, the bolt simply slides over the round in the mag.
A true short stroke rarely bites into the side of the next round since it won't pick up the next round.
Biting into the next round, or not closing the bolt fully (into battery) is usually a spring, buffer, buffer tube or friction issue.
The bolt *Should* slide easily forward WITHOUT catching on anything.
Shouldn't catch on any internals without a mag in place, shouldn't catch on the mag at all when it's in place.
All this is a forward stroke problem, not a 'Short Stroke' problem.
Sometimes the mag lock is simply in the wrong place and the mag sticks up too far.
Sometimes the mag will have bent lips or be incorrect and cause friction/drag.
If the bolt *Seemingly* moves fully to the rear, but bites into the side of the round in the mag...
Check to make sure you have the right length buffer AND the correct buffer spring.
Buffer springs ARE NOT interchangable between carbine & standard length stocks.
Buffer springs ARE NOT interchangable between AR10 & AR15 formats.
Some suppliers play 'Mix-&-Match', and it never turns out well for the builder...
I get a TON of builders that have leaking gas blocks.
'Also Ran' barrel & gas block makers tell you to slather up that block with 'Goop', thread locker, etc.
If the gas block didn't need pressed on/off, it's leaking. Slip fits ALWAYS leak and it's sloppy building to use a slip fit gas block/front sight block.
A ton of builders show up in my shop with mismatched buffers/springs for the stocks they are using.
Not just 'Cheap' springs that don't have correct spring rate, but all together the wrong number of turns.
This is usually from buying 'Economy' stock & buffer kits from questionable sources.
Springs bind (too many turns for a carbine stock) will drive you nuts!
Leaking gas key on the bolt is common...
Incorrect screws, not staked into place, leaking between key and bolt carrier.
Not all bolt carrier & keys have gas ports that line up, something to watch.
If it doesn't take solid thumb pressure to get the bolt to seat into the bolt carrier then the gas rings are junk or the bolt carrier bore is oversized (junk).
This isn't real common, but it happens...
Charging handles will cause the BCG to tip DOWN in the back when hand charging.
Fire cycling will force the BCG, more or less, stright back.
Look for a wear mark on the recoil buffer tube TOP where the BCG isn't quite lining up with buffer tube/lower.
I've found that AREO often doesn't fit well with common non-Areo receiver offerings.
If you find that knock/gouge/rub mark, the upper & lower aren't aligned.
Sometimes the carrier will show rub, or even aluminum smear on the back/top of the carrier.
Keep in mind the bolt BARELY gets a bite on the back of the second round.
If the mag lips bite into the brass, it will slow the BCG down and often allow the bolt to jump the back of the round resulting in the bolt biting into the side of the round.
Feed ramps/guide grooves will often have sharp edges that will bite into bullet and cause the bolt to skip off the back of the round, biting into the side of the round.
Most 'Builder' barrels/kits DO NOT have the feed ramp edges deburred or rounded.
Just some ideas from things I've run into, hope it helps.