I was doing the dry build on my RT tonight and have hit a bit of a problem.
I fitted the piston, pushed down the barrel as far as it would go, no base gasket and checked the alignment of the piston with the transfers - it's about 2-3 mm below. Odd, because it's a Spanish casing and while I know some of these can be a little high at the gasket face, I wasn't expecting that much.
Looking round I can see the barrel isn't all the way home. I think it must be hitting the casing on the spigot.
I take it off remove the piston and refit looking down the barrel the spigot is definitely well short of the casing.
Off it comes again and I check my SX barrel back on - it goes down all the way. I check the spigot length and the BGM is actually shorter in the spigot by about 1.5mm.
I push the barrel back on and it's definitely coming to a hard stop with a distinct 'tink'.
I pull it up and down a few times till eventually I get a little witness mark -
Turns out it's hitting on the back of the mag flange where the additional base gasket area is (arrowed)
Anyone seen this before?
I'l thinking to relieve the area where the witness mark is with a file to clear the mag flange. There's plenty of meat for it still to seal.
Anyone think I should relieve the mag flange or possibly both?