FX Impact M3 slug or pellet port?

[Floridaman2005]

So I got my M3 from a local dealer and have a few questions.

1. I got my M3 and tuned it and everything seems to be shooting great, but I discovered it’s on the “slug” port on the barrel. I am shooting 18.1 grain pellets. Is there any benefit or detriment from using the slug port over the pellet port?

2. Is it normal for my regulators to creep a bit overnight? Maybe gaining 5-10 bar or so in a day. I’m noticing that both regulators are creeping. Front reg maybe 10 a day and rear 5. Can this harm the gun in any way? Should I attempt anything m, bring it to dealer, or let it be?

 

[Airmanator]

I have a mk2 and m3. I leave both on slug port. Slug port will have a larger transfer hole so more airflow and power. But can still be use with pellets by lower power wheel or turning valve by the bottle inward. As for 5-10 bar creep is normal. If you have a chorny and measure your shots, the first shot will be lower by 30-40 fps. That is normal. 99% of all impact does it. There is a rare 1% ppl claim they don't have any creep. Mine will creep about 10 bars overnight. I clean and polish the piston and screw and now it's only 5 bar creep overnight. If you know how to take it apart, try polish the piston and adjust screw. It may lower the creep but will not eliminate it. Reg creep does not hurt the gun. Ppl just hate it cause 1st shot is always slower cause hammer have to work harder to open valve.

 

[Floridaman2005]

Well mine creep up, wouldn’t that result in the first shot being faster? I usually dry fire one shot before I take my chrony string. Seems to level out the pressure before I start shooting for accuracy.

I do not know how to take apart the piston and adjust screw. Is there a video or instructions on the how to steps for that? I’m relatively new to the PCP world and this is my first PCP.

I dialed in my pressures and hammer and valve adjuster and it shoots fantastic. I just didn’t know if there were benefits to using the pellet port. I like how it’s shooting with the slug port. I’m shooting 890-900 fps with 18.1g on 120/85 regs (500mm barrel)

 

[LDP]

No if you have your rifle tuned correctly higher reg pressure will lower the velocity not increase it. You should be tuned on the knee of the reg setting. Meaning the hammer doesnt have enough force to fully open the valve. So if the reg creeps up its going to open less causing lower velocity.

 

[Floridaman2005]

No if you have your rifle tuned correctly higher reh pressure will lower the velocity not increase it.

Ahh interesting. Good point…didn’t think of that at all but that makes complete sense.

 

[Floridaman2005]

No if you have your rifle tuned correctly higher reg pressure will lower the velocity not increase it. You should be tuned on the knee of the reg setting. Meaning the hammer doesnt have enough force to fully open the valve. So if the reg creeps up it’s going to open less causing lower velocity.

This is how my strings generally look for my first 10 shots. Is it normal to gain a little speed towards the end? I like how it’s performing but didn’t know if it indicates anything else I may not know.

 

[LDP]

Yes the speed increase at the end is the balance between the hammer and tank pressure. Being tuned on the knee will cause the increase. So as an example if the hammer energy is set to fully open the valve at 1800 psi and the reg is set at 2000 psi you will see velocity increase when the pressure drops off the reg until the pressure hits 1800. Then it will start declining again.

 

[MongooseV8]

That is a nice shot string, and what is expected with a well tuned FX. I have had several different FX pcps, all used and none have had any creep with fresh orings. FX has had issues with the AMP regs creeping though, that has been well documented especially with the older style plastic pistons.

The slug port is going to give you more fps than the pellet port on the same tune. There isnt really any downside, other than some specific pellets might catch when feeding. This will show up as fliers opening up your groups, but most pellets feed great with the slug port.

 

[LDP]

Depending on how far down from the reg setting the hammer energy is at will determine how much jump you see when the pressure drops of the reg setting.

 

[Floridaman2005]

Yes the speed increase at the end is the balance between the hammer and tank pressure. Being tuned on the knee will cause the increase. So as an example if the hammer energy is set to fully open the valve at 1800 psi and the reg is set at 2000 psi you will see velocity increase when the pressure drops off the reg until the pressure hits 1800. Then it will start declining again.

Is this a good thing or is there something I need to fine tune?

 

[LDP]

Non its fine. All you need to worry about is if the hammers energy is too low causing a larger jump than you want. Thats based on personal choice and how you want it to perform. I usually like to see 10 fps or less jump since my tunes hold single digit easily with regulated rifles. That way if I take a longer shot and it happens to be at the point of velocity jump it wont cause a poi issue.