Lee Enfield No.5 MK1 Headspace issue?

I bought this No.5 MK1 last week and it arrived yesterday. So today I took it to the range to see how it shoots and after I fire two test shots I found that upon examination of the brass I see what appears to be a head space issue. My question is, if my assumption is correct and it is head space and not a worn out chamber would I be able to swap out the No.0 bolt head currently on it with a No.4Mk1 No.1 or No.2 Bolt head to remedy the issue?

https://www.milsurps.com/images/impo..._zps6f3b-1.jpg

First test shot
https://www.milsurps.com/images/impo...ca371deb-1.jpg

Second test shot
https://www.milsurps.com/images/impo...04ce3c60-1.jpg

Your fired cases show normal expansion ahead of the solid web, not a headspace problem.

https://www.milsurps.com/images/impo...0/1qh9fq-1.jpg

Normal "scuffing" above the web is often confused with the "bright ring" indicating incipient separation. The two effects are quite different. Some examples -

https://www.milsurps.com/images/impo.../29n9p8z-1.jpg

See Milsurps Knowledge Library - Headspace 101 for .303's for detailed explanation.