i ran my SBR in a tactical carbine/pistol course last week and have 8-10 double feed issue. true double feeds (two live rounds, one in the chamber and another trying poke the first in rear)

my SBR is a radical firearms upper
palmetto state armory lower
fixed low pro gas block
spikes tactical T2 buffer
standard buffer spring weight
BCG has the BCM upgraded extractor spring and o-ring
i was using reloaded ammo

i was using 12 different 30rd pmags, it happened with multiple magazines
i switched out my BCG from my delton 16".......still had the same double feed issue
then i ran my pmags on the delton 16" with zero issues
the ammo ran fantastic in the 16" also, zero issues

..............this makes me think
1) its not the magazines, they did great in the other 16"
2) its not the BCG because the SBR had the same issue with both BCG and the 16" had zero issues with the same BCGs

i tried looking around for answers, but very little on double feeds that not magazine related

my only thought is.........what if i'm over gassed causing the BCG to hit the buffer sooooooo hard (i think this is called over functioning) that it jars 2 rounds loose from the magazine.

don't know if any of this makes sense.......but the last thing i needed was a double feed malfunction drill while practicing vehicle extraction drills....really slowed me down

thx for all ur help and advice.

im not sure if i need to up the buffer to and H3 or get a heavier buffer spring........i did measure the distance of the gas port to the buffer tube 1/4" (by taking the spring out, dropping the buffer down in and then the BCG.....it did not hit the buffer tube)

ARCHIVED THREAD - Help!! Double Feed problem

that's a great thread, i appreciate u posting it.

it really only mentions
-the gas rings.......mine are fine, i checked them
-the gun being dirty......i cleaned it right before this class
-the gas key being dirty.....i used 2 different BCG, both had the same double feed (2 live rounds)
-the gas block being loose......i checked it.....its on REAL tight



anyone else help me out pls?

i thought about putting the 10.5" upper on my delton lower and seeing if i get the same issue (that would at least narrow it down to an upper or lower issue


what do u guys think?

no. those feed fine. the double feed is after firing a shot. the spent casing would extract and eject. then i would get a double feed with 2 live rounds

thx dano523,

i tried the mag test.....they function fine (which i thought they would, since all 12 off them worked perfectly in my 16" without any double feeds)

when u mentioned not enough spring tension or buffer mass..............i have a T2 buffer (spike's tactical) and the standard spring that came with my PSA lower. do u think i should adjust those? if so, which one first? do u have a recommendation for what kind of spring to get?

Dano523,

thx for the input

i remember when i was at the range.....the bolt always locked back on an empty magazine. i didn't look at the brass though to see if the rim was bent. i wish i had.

i checked the charging handle like u suggested. the bolt face stops 1/16-1/8" from the back of the ejection port. as far as spring strength.....the last inch feels a little heavier that it does in the middle.

i agree with you that i have too much gas pressure pushing the BCG for the amount of buffer/spring pressure. can u recommend a spring that i should get? (brand and strength). or should i just go for an H3 buffer? i'd love to order something so that i can hit the range again and see if i get the problems ironed out

Not to be a dick but I would really look at a better upper then use factory ammo.  The rest of your set up looks fine.  I bet the issue is with that Radical upper somewhere.

i figured i would post the solution.......upgraded the Spikes T2 buffer (4oz) to a spikes T3 buffer (5.4 oz)......made all the difference in the world. my brass was ejecting at about 3:30-4 o'clock (before it was 2:30). not a single double feed. i think it slowed it down just enough to eliminate the jarring from the bolt and the extra round wouldn't pop out of the mag.

just too much gas pressure.

thx to everyone who posted a reply, helped out a lot