View Full Version : Single shot L1A1

February 22, 2017, 18:23
I purchased a Century L1A1 from a local gun show. I'm aware that Century aren't known for the quality builds, but I wanted to get into the platform and thought for the price I'd give it go. When I got it into my work shop and removed the zip tie holding the bolt. I noticed a good amount of rust and pitting on the bolt. Seeing this I began to inspect the gun closer in the much better lighting of my shop. The entire gun had several layers of paint or whatever covering tons of pitting and corrosion.

I started removing the entire finish to look at the extent of the damage. After doing so I thought it'll be alright as long as it fires and I'll just recoat it. Well it didn't, it fires only one shot and makes not attempt at charging another round. So I rotated the gas plug 180 degrees and still nothing. I ran it through all gas adjustments and still nothing. It doesn't even want to jam, it seems that no gases are getting to the piston to move the bolt. I disassembled the gas system and lower (for giggles) and I noticed that the gas tube is missing the little pin that keeps it from rotating and I know that the gas tube has to be screwed in a proper depth? Would this cause my problems or what else should I check?

I apologize about the long winded thread but I wanted to give the back story.

February 22, 2017, 20:15
the pin stops the tube turning and blocking the gas hole. it also stops gas loss out of the pins holes.

is it all inch or a mix and match?

February 22, 2017, 20:51
the pin stops the tube turning and blocking the gas hole. it also stops gas loss out of the pins holes.

is it all inch or a mix and match?

I have no idea on the mix match, and that's what I thought it did. When I reassembled it I didn't tighten it enough to cover the gas hole but I assume it can move since it isn't pinned

February 22, 2017, 20:58

February 23, 2017, 09:13
Post pictures please, it will help in getting your issue diagnosed.

February 23, 2017, 10:13
Also make sure that the gas regulator is not backed out over a full turn. I learned that lesson the hard way. Tighten it all the way down and then go through the adjustments.

February 25, 2017, 09:35
Also make sure that your gas plug is in the right orientation. If its 180* out, it's a single shot rifle. The push button should be on the left hand side of the gas block for normal operation.

February 25, 2017, 10:26
When you assembled the gas tube back into the rifle and are clueless like me, look through the gas plug hole with a flashlight as you screw it in. There is a bit of a shoulder on the gas block an you want to get the tube as close to that as possible without forcing (the pin is what holds the tube from backing out). I was scared, based on some threads here, about bending the tube so I stop tightening it as soon as I found *any* resistance. As a result my IMBEL was a single shot whose bolt carrier was not able to unlock the bolt much less removing the empty cartridge. The telltale was covering the gas block where it met with the tube with talcum powder and watching it be cleaned out when I fired, indicating gas was escaping around the tube.

AFAIK, you do not need the pin if you are just testing things out. Friction should keep everything in place for a few shots.

BTW, did you check if the gas hole between gas block and barrel is clean?

Capt D
February 25, 2017, 11:56
I know some folks might LocTite the threads on a worn gas tube, but an alternative is to brake clean the threads well, wipe them down with alcohol, then use high heat (1200 deg) Rustolem, or similar, enamel on just the threads. Do 3-4 coats to build up, allow to dry for an hour, then install. This will help reduce excess gas leakage, and won't require oven-baking to remove, as LocTite often does. Do this before investing in a new gas tube, to save urself a few bucks. Just another option for ya...