Is there a definitive way to measure ejector tension? Or do you just measure the ejector spring?
Measuring the spring is a relative pita even with a jig to hold the ejector in place while you drive out the roll pin. I mean, it’s not like pulling an action spring to measure free length… The last time I had a carbine that was having intermittent ejection issues I pulled the bolt and hooked a cartridge rim on the extractor claw and levered it down flush. I could tell right away, by feel, that the spring was weaker than what I was expecting and replaced it.
I suppose you could use a trigger pull gauge using the technique above on a new spring (installed) and then check it against other bolts. Yep, not definitive by any stretch, but I’ve never known any other way. Perhaps the knowledge base here will enlighten us.
Flick test. Remove the BCG from the rifle. Insert the rim of an empty case under the extractor and with your finger on the mouth of the case, compress the ejector. Then, flick your finger back and let the empty go flying. It should go about ten or twelve feet.
Nice. Been wondering how.
I just use a pin punch to push the ejector into the bolt, if it feels like mush is needs to be replaced.
Pretty much this, it should be a bi*ch it push in with just your fingers combined that with seeing where your brass lands should tell you if your spring has gone bad.
I little tidbit to accomplish two task with one act. After cleaning the bolt, place a drop of your favorite monkey jizz on the ejector and press the ejector in(I like to use the cam pin) 3-4 times to test the tension and get lube into the ejector pocket.
The force required to push the ejector flush to the breech face should be 9.9 pounds . . .
What is the method for checking that?
I haven’t seen any Armorers use anything like that.
Armorers? They just see if it flicks the case a few feet.
I have always taken a EMPTY cartridge and done the “Flick Test” .
Mine usually fly 6 to 7 ft. because I use a Sprinco Ejector and Extractor spring, between those 2 she will get a cartridge out of the rig.
Or tare the damn extraction grove off the cartridge under the extractor. 
And that’s all the ejector needs to do.
Using a trigger pull gauge on an ejector is classic overthinking.
Except that the gauge tells you how soon the spring is going to be out of spec. Numbers don’t lie, and are much more concrete than “good 'nuf.”
What kind of gauge do you use?
Same one as you. [emoji12]
What is that supposed to mean?
As I’m merely an enthusiast and neither an armorer, nor a 'smith, I don’t own a gauge; just like you.
The local smith close to me basically goes by feel and flicking a empty case. He is the go to dude around home. About all he works on is AR’s and AK’s that is his thing.
Also I enjoy your posts, you ask alot of tech questions and I really enjoy reading the answers.
Thanks.