How does my tune look like and any suggestion?

[RayK]

Yes, it is common. When you are on the downside of your shot string, the shot noise will sound a bit louder and there is likely more air wasted per shot. The guns are more efficient on the high-pressure side of the shot string.

Your shot noise is reduced because you have a relatively short hammer throw.

Ray

[Mapuia]

Thats exactly what i experienced. I just found ufc pro chorno, should i get it?

[npunk42]

Thats exactly what i experienced. I just found ufc pro chorno, should i get it?

That's an interesting little unit. Since you have to put the muzzle so close to the box your actual numbers may be a bit different than what you see here. Most guys here place their chronys 2-4 feet away from the muzzle. Whats important is the relationship from one shot to the next, and that's what this chrony will give you. It looks like it is made for airsoft guns, be sure it will detect velocities like those from your marauder before you get it.

[Mapuia]

Thanks Ray. I contact the seller and i was told it can be used for pellets as well so i have ordered it, i will post my strings again after i receive it. By the way i have some questions regarding hammer spring durability. I have set my spring tension to 4 turns cw. Can you tell how much this setting shortens the springs durability? Am i giving to much tension.

[RayK]

Can you tell how much this setting shortens the springs durability? Am i giving too much tension.

You're fine. Springs are cheap anyway.

Ray

[Mapuia]

In my tune right now my valve is 2.75 cw, HS-8cw and HT4cw, to get a more flat shot string @ a maximum velocity of 850 fps with 2600-2800 max fill pressure will opening up the valve one turn and shoter HS do the job?

[RayK]

No. It is all trade-offs. If you want a flatter shot string, you must lower your peak shot power so you are using less air per shot.

Ray

[Mapuia]

Ok, and a question Ray, based on your experience how many good shots can be tuned out from a .22 marauder with 18gr jsbs with stock parts?

[RayK]

At higher power, in Gen I, about 31 good shots within 3-4%. In Gen II, you can probably get 35-40 good shots per fill. With valve and hammer spring modifications, you might be able to get 50 good shots per fill. That's what I'm getting in my 22, but I have to fill to 3100 psi.

Efficiency is better at the start of the shot string and Marauder valves have better efficiency at higher fill pressures. The number of good shots per 100 psi is very high up at 3200 psi, but it drops as the pressure drops.

Some have modified valves to get great efficiency and power at lower fill pressures. Travis at Wicked Air Rifles and Douglas PakProtector are two I know of who have accomplished this.

Ray

[Mapuia]

Since I am using hand pump i am aiming for max fill of 2800. I will try to tune for 35-40 shots within 3-4%