Gen1 Marauder .177 Huma

Hi I recently bought a 2nd hand Marauder .177 in excellent condition.
I already bought all replacement oring and a huma regulator with a gauge replacement.
Now it's the first time tuning a Marauder and I would like to have a guide regarding the setting of the regulator pressure , turns of spring tension and turns of hammer . My target is to shoot 10 gr slugs or jsb pellets as accurate as possible.. I suppose about 950fps will be the sweetspot for slugs.
Any input will be greatly appreciated!
 
Hi I recently bought a 2nd hand Marauder .177 in excellent condition.
I already bought all replacement oring and a huma regulator with a gauge replacement.
Now it's the first time tuning a Marauder and I would like to have a guide regarding the setting of the regulator pressure , turns of spring tension and turns of hammer . My target is to shoot 10 gr slugs or jsb pellets as accurate as possible.. I suppose about 950fps will be the sweetspot for slugs.
Any input will be greatly appreciated!
you may want to look at Tim Hill's parts , since now your not shooting from 3k to 2k and refilling , the regulator keeps you around 1900 psi in that little pocket of air that your valve will now be seeing , so removing restrictions from your valve - transfer port - and barrel where the transfer port goes to will make your gun work much better , a lighter valve spring "or" a tim hill valve with a light valve spring installed by tim hill before shipping , Anyway " a lighter hammer and hammer spring , tim hill has a few that are short enough to give you free flight , "so less hammer bounce " if you dont do anything but put a reg in you wont get enough power and a very low shot count , gen one requires a different hammer spring guide for newer hammer springs , tim hill sells the part , all this seems like alot , but it works , its fun , ive done 3 of these , one like yours gen 1 , all have come out good , any way ..... something to think about , if you just want more power maybe leave the reg out and open the valve up all the way get a polymer transfer port and i think tim hill has a drill bit and hone for your barrel transfer port that would get more power , regulated is probably the best way but takes a little more to make it work good , let us all know ! and have fun ! cause its fun doing these things !!!
 
What Joelayfield said above is right on. I have a gen 2 Marauder. I installed Huma regulator(set at 1700psi), Tim Hill light weight hammer, hammer spring and valve spring. I did not do any porting. I can go from 10 fpe up to about 21 fpe with hammer spring adjustment. So, the JSB .177 13.43 monsters go 840 fps. I usually shoot them around 18fpe or 775fps. The Tim Hill parts work great!