round wont eject on 7.5 AR Pistol

[Dustbuster]

Home brew AR pistol,new,using amer eagle 223 55 g ammo
pistol wont extract fired round unless its done manually.
am inclined to believe its gas block issues;
any input appreciated especially trouble shooting process.
am leaning towards:
Temp swap bolt cg w known working bolt cg to eliminate extractor issues
re check gas block for alignment of ports/holes
Have already checked for obstructions in the gas tube,none

could this be a timing issue? and if so how do you check
upper was setup and checked,got it from J and T
thanks in advance Edited December 5, 2012 by Dustbuster

[Dolomite_supafly]

Timing is only an issue with full auto AR's, not semi autos.

It is a gas problem. Either the gas block is not lined up right or the gas port is not big enough. Also check your gas key to make sure it isn't loose. Something else I ran into, make sure your gas tube is fitting tightly inside of the gas key. Like any short barreled gun it will be finicky once you do get it running.

Is is partially unlocking and just not ejecting?

Can you verify the gas port diameter?

With it being from J&T anything is possible. I have seen and heard some horror stories about the stuff that makes it out of their doors.

Dolomite

[Dustbuster]

ill get the measurements,partial unlocking is possible, face of the bolt had a burned look to it.
thanks

[Oh Shoot]

[quote name='Dustbuster' timestamp='1354714083' post='855197']
ill get the measurements,partial unlocking is possible, face of the bolt had a burned look to it.
thanks
[/quote]

I don't know much re these, just still interested in getting one myself -- but I think Dolomite meant to determine whether it is getting enough gas pressure to unlock at all after firing or if bolt simply stays locked into chamber?

What kind of buffer tube arrangement you running?

I doubt appearance of a "burned" bolt face means anything, I guess mine could be described that way.

- OS Edited December 5, 2012 by Oh Shoot

[Lumber_Jack]

[quote name='Oh Shoot' timestamp='1354742266' post='855379']

I don't know much re these, just still interested in getting one myself -- but I think Dolomite meant to determine whether it is getting enough gas pressure to unlock at all after firing or if bolt simply stays locked into chamber?

What kind of buffer tube arrangement you running?

I doubt appearance of a "burned" bolt face means anything, I guess mine could be described that way.

- OS[/quote]

Get a range trip together and you can shoot my .300BLK pistol


OP, did you look to see if the gas port was was at 12 O'clock on the barrel? Heard of some barrels having misaligned ports. Or as Dolomite suggested, could just be the block not lined up. Edited December 6, 2012 by Lumber_Jack

[Dolomite_supafly]

[quote name='Lumber_Jack' timestamp='1354751956' post='855454']
[color=#FF0000][b]Get a [/b][/color][color=#0000FF][b]range[/b][/color][color=#FF0000][b] trip [/b][/color][color=#0000FF][b]together[/b][/color][color=#FF0000][b] and [/b][/color][color=#0000FF][b]you[/b][/color][color=#FF0000][b] can [/b][/color][color=#0000FF][b]shoot[/b][/color][color=#FF0000][b] my [/b][/color][color=#0000FF][b].300BLK [/b][/color][color=#FF0000][b]pistol[/b][/color]


OP, did you look to see if the gas port was was at 12 O'clock on the barrel? Heard of some barrels having misaligned ports. Or as Dolomite suggested, could just be the block not lined up.
[/quote]

Yes, it has been way, way to long since my last trip to the range.

Dolomite

[Guest nysos]

Going to be getting mine to the range soon to do a function test.

[Dustbuster]

OK here's the deal,problem solved.
I yanked the gas block etc last night.Evidently the port in the barrel was clogged with trash,rusty nasty stuff.I took a small bit and cleaned it out,punched the barrel to rid debris, done.Next step, the gas block hole and gas port were not properly aligned after the mfgr re installed the gas block.Port in the barrel was at 12 oclock. The hole in the 4 rail version is at a diff distance than the single rail block.properly installed with good alignment there should be a 4 mm gap between the edge of the block and the edge of the grip where you can barely see the gas tube. Bottom line is after cleaning the port and re aligning the gas block alls well,fired 2 test rounds,it cycled just fine.
The lesson learned is the gas block and barrel port alignment and flow should be checked during the build or rebuild especially when maneuvering components,but don't fix it till its broke.When performing any operation with the barrel take the time to clean the port. This upper was brand new.I was told "all of our uppers are test fired".........well ,last but not least i've learned to make port alignment part of my checklist,timing applies to autos,and when in doubt check basic specs,never forgetting when you hear hoof beats think horses not zebras.
Thanks for the help guys! Edited December 6, 2012 by Dustbuster

[Dustbuster]

port alignment update :
i opened up the hole in the aftermarket block to be in line with the hole in the tube. i did this because the pistol started showing ejection malfunction.
ran 5 rounds through it today to test all good.
other lesson learned: be careful with what u buy at gun shows ie where i bought the 4 rail block. I think the person i got the block from got a deal on blocks w hidden issues.
anyhow all good just wanted to pass it on

[53caddy]

I had the same problem today. Just got the BCG in today went to the field and it would not eject a spent round. The issue the hole on the gas block was not alligned to the hole on the barrel.

[Dustbuster]

I believe that if there is anything that will interrupt the gas flow,the pistol will rear up and puke.the gas port is about 1/16 in dia.the hole in the gas block was almost 3/16.The gas tube hole wasnt lined up right as well,so i aligned everything using a dremel,dig caliper, and 20/20 vision. re assembled again tested works good.Of course ill fix it till its broke because its been my problem child.well see how it works when the noveske pig arrives..... <efg>
actually ran 200 rounds through it this afternoon ran like a sewing machine, thanks for all the help from everyone. having all 3 holes ligned up where theres nothing inhibiting the gas flow seems to be the trick,making the hole in the 4 rail block oblong didnt upset anything Edited December 9, 2012 by Dustbuster