Ejection Problems...

[rocketboy]

Hi all. Got my L1A1 kit on a DSA group buy receiver out to the range today!!! It finished out pretty awsome, though had a hard time getting the park on the lower to finish out evenly, Ive even seen some at the shows that came out the exact same way... anyway thats besides the point... 1 foot off to the right at 225M, and 2 turns low...

heres the problem... I think its a multiparter... first is the gas tube pin keeps backing out if youre on the lower gas settings as the collar doesnt capture it on the left side... what to do? The original looked pretty coroded... what size/type pin here for a replacement?... I think this may be part of the ejection problem... well, the bolt hold open will catch on a gas setting of 6/5, that was until I had a ejection failure, so I tried to up the gas and see if that helped, thats when I noticed that the collar wouldnt turn and the pin had backed out, so then I got it back in and cranked it down to 4 so the collar would capture the pin. A few more rounds and I began to have failures where the case would unchamber, reverse itself, and end up jammed atop of the chambering round. What was ejecting was ending up at 4 o'clock at my elbow with some showing some nice extractor claw marks on the rim.... managed to trash 60 winchester white box reloadable cases... American Eagle, and some reloads seemed to be fine except for 2 out of 60 crunched...

anybody seen this before? Tapco piston sanded down to .435 to a tight fit, bottom of receiver deburred, stock cover, STG metric mags, FAQ read.... out of ideas... GP's response to one indicated wrong ejector length amoung other things?...

ideas?


TIA!!!

[herman07]

Start working them out one at a time beginning with the gas tube pin. The process of elimination will eventually get you running smooth. There has been lots of talk here lately about "sticky" chambers and the need for LIGHT polishing in the chamber.

I would start in the front of the rifle and work my way back, eliminating, timing, gas system, ill fit bolt/carrier, ejector, bolt hold open (must be an added option because I did not think inch guns came with them), then chamber as last resort.

My home build ran great from the start and I have never had to troubleshoot any of these issues that you are going through. My advice is only based on what I have read here from the very knowledgable persons who frequently post here.

Get Gunplumbers workbook, I think it has a good troubleshooting section.

[ September 04, 2001: Message edited by: herman07 ]

[herman07]

Just re-read your post. May be timing issue with piston binding (1 foot right at 225m). Possibly overtimed a bit. See if the piston binds.

gary.jeter has a formula to determine how far out of time based on point of impact.

[ September 04, 2001: Message edited by: herman07 ]

[Blood of Tyrants]

First, does the gas tube fit tightly or is there quite a bit of wobble? If there is a lot of wobble, tinning the threads with silver solder might help tighten them up. Tinning is a process where a thin coating of silver is applied to the threads to build them up.

The pin is 5/64" in diameter. Just put red Locktite on it before installation.

FAL's are bad about destroyong cases. With surplus ammo so cheap, it doesn't make economic sense to reload them.

[W.E.G.]

Sounds like a mo' beans issue.

More gas pressure should solve that failure-to-eject problem. You can accomplish that by closing the port more, or installing a fatter piston or a tighter tube.

Also be sure the gas piston is not dragging on the area where it passes through the receiver. This could be related to your timing issue.

Rotating the barrel one degree will move your point of impact five inches at 100 yards.

Moving the sight .006" will move your point of impact one inch at 100 yards.

[ce]

The only problem is the gas tube pin.
If it is even a little loose, enough gas will bleed out of the hole to disable the rifle.
Make new one, and peen the end if need be to secure it.The gas regulator was holding it in place until you allowed it room to move and the gas then blew it out.
Mine did the same thing, field expedience dictated the repair, a pin fabricated from a piece of barb wire fence.
If it shoots to the right, it's in too tight, although a foot at 225m should be within adjustment of the sight. Off a foot at 25m is another story.

[rocketboy]

Thanks for all the help guys! A 5/64 x 1/2" roll pin is indeed correct, the corners just need dremeled off to clear the regulator, thanks for the red loctite tip too!!!! It is correct that the tube is about 1/4 turn short of bottoming out correct? Tightening it will bind eveyrthing up. Thanks for the silver solder on the threads tip too! Will have to do that just to be sure!!! Timing does NOT appear to be an issue in this case, the piston slips neatly down all the way thru the receiver. In fact, this build is closer to being timed correctly than anything else Ive bought new or used! There is definatley enough gas there, it will bend up the rim where the extractor grabs it on 4! On about 6 it seems to eject to about 2 o'clock but 1 in 20 cases ends up jammed. I initially thought that it wasnt enough gas too, but increasing the gas makes it jam at least 2 out of three, and the ones that do get away end up at 5o'clock with seriously mangled rims where the extracter yanked them. It is *feeding* AND *extracting* like its supposed to, its just not *ejecting* them out of the dust cover before the next round tries to chamber. The wierd part is that they end up jammed in there backwards ontop of a chambering round. Could it be a weak piston spring, and or the ejector needs trimmed? What is the relation?

THANKS again all!!!!!