Lyman Borescope - Convert to Straight View?

[Rum River]

I bought one of these years ago and still use it. If the Teslong had been available back then I wouldn't have bought the Lyman.
I would use my Lyman more if I wasn't locked into only looking 90 degrees.

Anybody tried any tricks with their Lyman to look straight down the barrel?

 

[Old Rooster]

My neighbor has one and the tip screws off so he can put the 90 degree tip or straight tip.
Don't know about the older ones