Tuning Marauder cooking effort.

[phillips4100]

I would liike to hear from other marauder owners on their experiences. I have been building a custom.25 marauder. It's a bottle conversion, regulated and I'm trying to achieve about 100 ft lbs (shooting 55 grn nielsens). To get the velocity I'm looking for, i have the reg set at about 165bar. I'm running a drop in valve from jsAir, but I've also run a cothran valve. The idea with the balanced valves i thought, was to be able to open them easily using a light hammer and very little spring pre-tension. In my experience though I've needed a lot of spring to open the valve enough. I'm 6'1 230 lbs and pretty fit and it's really hard for me to cock the gun. Has anyone here had experience with either of these valves, or maybe has som advice on how to run this valve / hammer combination?

 

[OldSpook]

I'm thinking even if you manage to cook it, it will still be tough as hell.

 

[SDellinger]

I had a gen 1 Marauder with the bolt. It got very hard to cock. I put some lube on the hammer and that fixed it. 

 

[TG59]

phillips4100,

What type of bolt do you have on your Marauder?

 

[nervoustrig]

Looks like an aftermarket side lever breech, in which case the cocking effort should be easier than the OEM bolt. Assuming the side lever is working correctly, that is.

Otherwise it sounds like the valve may not be functioning as a balanced valve.

 

[phillips4100]

Yeah, same issue with the OEM bolt and the one on the side-lever. I've tried several different hammers OEM, aftermarket, free-flight and otherwise... thinking maybe it's just a marauder design issue.

 

[sb327]

Just a thought,

you mentioned a light hammer. Opening the valve is only part of the dwell of the valve cycle. Although a light hammer can open the valve to the same distance as a heavy one, it will close faster due to being a lighter mass. 



When chasing power, a heavy hammer can help, some. 


It does seem as though the bv is not giving all the help it should. 


Dave

 

[fivestar45]

My experience with Don Cothran's valve was that it took very little striker spring to open it.

The amount of force you mention to cock the action sounds off for sure. I'd call Don.