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Benjamin 2015 Marauder 25 cal low velocity

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Bigtwin69

Bigtwin69

Member
May 23, 2015
29
17
Oklahoma
My 2015 25 cal Marauder is stock and I assume is a Gen 1. When I first bought it I recall it shooting in the low 800's using JSB's 25.39's. The last couple years it's shooting in the upper 600's and is accurate. My preference is to get the velocity back up in the low 800's. I've search youtube and forums trying to find a solution for increasing the velocity. I've opened up the valve metering 4 CC turns and have backed the spring off and turned it CW one turn at a time but the velocity seems to stall in the 680's. It appears not to leak off pressure while stored.

Are there parts I need to replace to regain velocity?

I've followed the information in this link down through where it mentions increasing hammer tension 1 turn at a time.

Tuning a Marauder- What to adjust and where to start

Found this while researching how to "tune my Marauder". As he states it is not a "how to" but rather a what are the components and a starting place. Thought this might be of help to other Marauder shooters. This was written in 2009 most likely for the Gen 1 but will apply to the Gen. 2 model. He...
www.airgunnation.com www.airgunnation.com
 
Bigtwin69 said:
Found a post about the o-ring after I posted.....I checked and my o ring is absent.
Click to expand...
O-ring may not be technically absent. Look at the base of the charging pin with the bolt closed. Most times it gets blown out of the barrel and around the pin. This happens when the gun is fired and the charging handle not locked up. The .25 has a clear amber urathane o-ring. May need a flashlight to look into the back breechblock.
Gen1 = ‘10-‘13
Gen2 = ‘14- present
 
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Airgun-Revisions said:
O-ring may not be technically absent. Look at the base of the charging pin with the bolt closed. Most times it gets blown out of the barrel and around the pin. This happens when the gun is fired and the charging handle not locked up. The .25 has a clear amber urathane o-ring. May need a flashlight to look into the back breechblock.
Gen1 = ‘10-‘13
Gen2 = ‘14- present
Click to expand...
thank you...Since I bought my Marauder in March 2015, I must have a Gen2. Thanks for the information. I'm attaching a couple of pics. Is the O ring at the rear of the breech the "blown out" o-ring?

IMG_9033.jpg


IMG_9034.jpg
 
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That does look like it might be it, but the groove is in the barrel, so to see if it is where it is supposed to be you have to look at the other side of the mag slot from the pictures. It does no good on the probe - it has to be in the slot. if it ended up back there as shown in your picture you'll have to fish it out and get it back in the slot. They are tricky to get seated in the slot - a dowel up the barrel as a support helps a lot.
 
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Bigtwin69 said:
thank you...Since I bought my Marauder in March 2015, I must have a Gen2. Thanks for the information. I'm attaching a couple of pics. Is the O ring at the rear of the breech the "blown out" o-ring?

View attachment 420332

View attachment 420333
Click to expand...
Second pic. Check to see if it’s around the base of the bolt probe. If it’s there remove it and insert it back into the barrel side.
 
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Airgun-Revisions said:
O-ring may not be technically absent. Look at the base of the charging pin with the bolt closed. Most times it gets blown out of the barrel and around the pin. This happens when the gun is fired and the charging handle not locked up. The .25 has a clear amber urathane o-ring. May need a flashlight to look into the back breechblock.
Gen1 = ‘10-‘13
Gen2 = ‘14- present
Click to expand...
Can I obtain a replacement o-ring from ACE vs a proprietary o-ring?
 
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