I was at the range the other day when a guy tries to shoot his CVA inline muzzle loader only to find that the cap that holds the striker spring in the reciever had broken. The cap was made of plastic. I know the more quality brands use a steel cap.
Just a warning to everyone who might be in the market for an inline.

My CVA inline came with a plastic cap as you mentioned, I never had any problems with it but it made me a little skiddish, so I made one out of billit aluminum at the shop. no problems so far. and it was a cheep, easy fix for my peace of mind.

Yup, I had the same problem, except mine broke from overtightening.  Just like his did.  It just took some pressure to make it fail.  The book says to turn it down till it touches the rear of the receiver.  Do not tighten!

Anyways, so close to hunting season, I used a threaded insert then drilled and tapped the end of the receiver for a set screw, counter bored the threaded insert, and off to the woods I go.

I don't care how rigged it looks, my ass is going huntin'.

All you damn inline pussies.  I took two on Saturday with my sidelock TC.  

Damn newfangled young'uns, don't 'preciate the old way of doin things...now where'd I put my teeth...mebbe I"ll just close my eyes fer a few minutes 'n' rest a bit...

Yeah, Gwigg, I can see how that would happen. But I wouldn't trust plastic to last forever in any loaded condition. I've never seen plastic contain a spring of any power for more than a couple years. Like those Mossberg trigger housings that were made of plastic. They always gave way after awhile too, no "tightening" necessary.