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Welcome to the Best of the Best! => Welcome New Members => Topic started by: GCGS on August 05, 2022, 12:39:49 PM
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Out of the box, my .25 Armada is shooting Hades 26.54 grain pellets an average of 798 FPS at 37.43 FPE. I’d like to bump that up a bit. I see instruction everywhere on the 3-step process for tuning the Benjamin. The steps include:
1) Adjusting the Velocity Metering Screw
2) Adjusting the Hammer Stroke
3) Adjusting the Hammer Spring Pre-Load
My question is: Can one simply adjust ONE of these settings without adjusting the other 2, or MUST I make adjustments to all 3? In other words, is there a “balance” necessary when making adjustments in that all 3 need to be tuned together to be in sync? If the answer is no and I can or should make only one adjustment, which of the 3 should I start with to bump up my FPS and FPE?
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Welcome to the GTA. David
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Welcome to the GTA David. 8)
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Out of the box, my .25 Armada is shooting Hades 26.54 grain pellets an average of 798 FPS at 37.43 FPE. I’d like to bump that up a bit. I see instruction everywhere on the 3-step process for tuning the Benjamin. The steps include:
1) Adjusting the Velocity Metering Screw
2) Adjusting the Hammer Stroke
3) Adjusting the Hammer Spring Pre-Load
My question is: Can one simply adjust ONE of these settings without adjusting the other 2, or MUST I make adjustments to all 3? In other words, is there a “balance” necessary when making adjustments in that all 3 need to be tuned together to be in sync? If the answer is no and I can or should make only one adjustment, which of the 3 should I start with to bump up my FPS and FPE?
I would first run a string from 3000psi and figure out where your curve is in that string before making any adjustments. When I got my .22 Marauder recently I actually found from 3000 psi I didn’t have a bell curve rather flat then, two magazines and it would drop off. I backed out the hammer spring I don’t remember maybe 1 turn leaving everything else alone and that did the trick for me getting more shots. If you want more power you can probably tried the hammer spring adjuster in some (keep track) and see what happens
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[smg id=8629]
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Welcome to the GTA.
Richard
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David. Welcome to the GTA!
I'm afraid that you won't get many responses since this is your Welcome post.
There has probably been more written about MRods than any other platform. I'll give you a quick shot of the things that I've learned by reading and by doing.
This is my short description of what these adjustments do for you.
The MRod has three adjustments for you to tune it:
HS, HT, VMS.
The trigger has adjustments for 1st stage, 2nd stage, trigger pull weight and trigger position. I think that the trigger position interacts with sear engagement so don't mess with that one unless you really need to.
So here's the thing about tuning:
All of the airrifles that I know of use a "poppit valve", it's like the Schrader valve on a tire. Push the little pin ( stem ) in the center and air escapes. The hammer slams the poppit stem to release a sip of air.
The hammer energy is adjustable, but it's constant once it's adjusted.
The energy required to open the valve depends upon how much pressure is in the tank.
Now here's the cool part:
1. when the pressure is high it's hard to open the valve, and it closes quickly. This gives a short burst of high pressure air.
2. When the pressure gets low then the valve opens easier and closes slower. This allows a longer blast of lower pressure air.
It kind of evens out, but you must adjust the hammer energy against the desired pressure range. (note 1)
The hammer energy is comprised of these factors:
Hammer mass ( weight ),
You would need to change parts to change hammer weight, there is no factory adjustment for that.
Hammer spring tension ( HS ),
More tension means that it hits the valve harder. This will open the valve at higher pressures, and it will open farther if you let it.
Note 1, If the pressure is too high for the hammer spring it may not open at all, this is called "valve lock".
If the pressure is too low for the current hammer spring tension then it may slam open, then bounce back against the hammer weight and spring only to open again, often several times. This is called " hammer bounce ".
Hammer Travel, or Hammer Throw ( HT ),
A longer throw means more hammer energy, and how far the valve opens. This affects how long the valve stays open.
You must balance these against the desired fill pressure. Just because the maximum fill pressure is 3000 psi doesn't mean that you must tune to that starting pressure.
You may very well use 3000 psi if you have a pump, either electric or hand pump, or SCBA tank that fills to 4500 psi. If you fill from a SCUBA tank you might want to choose a lower value like 2600 for a starting pressure.
VMS. Thus sort of evens things out. It does reduce the power of every shot, but it reduces the highest power more than the lowest power. It's just a screw that sticks into the airstream. I like to start by backing this all the way out so that it doesn't hide the small differences in the power curve. You can close this down a bit later to even things out.
Hunter
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Out of the box, my .25 Armada is shooting Hades 26.54 grain pellets an average of 798 FPS at 37.43 FPE. I’d like to bump that up a bit. I see instruction everywhere on the 3-step process for tuning the Benjamin. The steps include:
1) Adjusting the Velocity Metering Screw
2) Adjusting the Hammer Stroke
3) Adjusting the Hammer Spring Pre-Load
My question is: Can one simply adjust ONE of these settings without adjusting the other 2, or MUST I make adjustments to all 3? In other words, is there a “balance” necessary when making adjustments in that all 3 need to be tuned together to be in sync? If the answer is no and I can or should make only one adjustment, which of the 3 should I start with to bump up my FPS and FPE?
Simple answer... follow the instructions. No short cuts here. If you're looking for short cuts, buy a springer, and take what you get.
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Welcome to the GTA David!
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Welcome to the GTA!
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Welcome to the GTA, David!!!
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Welcome to the GTA. There is a lot of tuning info on the marauder/armada here on the GTA. There is a balance when tuning these rifles. Get a good chronograph and record everything. Good luck on your tuning adventure.
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Howdy
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Welcome to GTA Forums David!!!
SAFE & Happy Shooting!!!!
Dave
8)