The material is Type II PVC.
With this material you do need to clean and lube the barrel after each shooting session since you will produce some chlorides which will cause rust. With that being the case I use an alcohol swab between shots to ensure that every shot is just like my first cold clean bore shot.
For the 150 grain NAB 30 caliber bullet I normally zero at 300 yards so most of my whitetail shots don't require a rangefinder and only one adjustment to 400 yards.
I don't know the pressure for sure but expect it to be around 45kpsi +-, based on expansion and velocity.
If I shoot this weekend with the 250 NAB's I'll bring pressure trace and get a trace for each load.
Which 45 bullets do you normally shoot, and which sizing method do you prefer?
I don't shoot sabotless much, but either shoot 250 SST's or the 300 grain Remington that I modify.
For sizing I prefer what I call "mushroom" sizing
To make them you need to size from the base and not the ogive.
Most of the bullet shank is 0.4485 so it will fit easily and align in the bore, however the last 1/8 inch of the shank is 0.452 ensuring a positive engagement with the rifling.
These are the Remington 300 grain 0.458 bullets sized for sabotless and modified to slightly improve B.C.