Firing issues on my bitsa

[GB2017]

In keeping with my usual noob questions regarding rapids, I am in the following situation and would be grateful for some input.

So I bought a bad of bits from someone to build a 20 cal FrankinRapid, the bottle from another Rapid has a leak so that is getting some parts from Dr Bob when his life has returned to normal after his recent bad family news.

I purchased a gsx block from impact (bit like doing your own dentistry through your bottom) and put everything together with a trigger block from Dr B. After a bit of shenanigans with the cocking gate (?) cover cured by filing a Dr B's one to size everything got put together ok except when i cock it, it doesnt fire, i know the cocking dog is in situ so am suspecting there is something i havent done / interconnected properly, so thought i would reach out and enquire here prior to stripping it

thanks in advance

[KevG]

is it the correct hammer.as some hammers from series 3 triggers or sporter trigger will  not work on a series 4 trigger.
KevG

[GB2017]

is it the correct hammer.as some hammers from series 3 triggers or sporter trigger will  not work on a series 4 trigger.
KevG

that I couldnt say, is there some info somewhere that i can reference?

[KevG]

is the hammer actually going back but failing to latch onto the trigger sear
KevG

[GB2017]

is the hammer actually going back but failing to latch onto the trigger sear
KevG

I think so, i will strip it and post some pics. I do have a mk2 hammer for the mk4 trigger assy on order with Dr B

[KevG]

if you feel spring tension as your pulling bolt back at least you know dog is doing its  job on contacting hammer.
KevG