First of all, greetings, my name is Pablo, and I hope Google Translate is doing its job well, as I'm writing to you from Argentina.
I've followed many threads here and read entire posts about the BRK Bantam Sniper rifle, looking for information or, rather, a solution to a problem I'm experiencing with my rifle. This isn't a defect, but rather a characteristic of the rifle and its design. The first thing to clarify is that my rifle came from the factory firing at 39 joules, the regulator set at 135 bar, and it fires an 18gr JSB at 846 fps.
The problem I'm encountering is that I only get 45 stable shots (5 fps spread) at a velocity between 185 and 155 bar, which I understand is unexpected for a well-known regulator like the HUMA, and for a carbon tank that can be inflated to 220 bar according to the manufacturer and has a 500cc capacity. I understand that's very few stable shots. The total count is much higher, but with a spread of up to 20 fps. I should clarify that this is one of the first bolt-action models.
Reviewing the posts I've read here, some colleagues have played around with the hammer spring and pressure settings on the HUMA regulator, but without good results.
My conclusion at this point is that the lack of a plenum means that, at the moment of firing, there isn't enough regulated air available, and the regulator, with that pressure drop, lets air in at the same pressure as the tank, causing the shots to have a significant spread. This is most noticeable when the tank is between 225 and 185 bar pressure. After 185 bar, the subsequent shots stabilize somewhat, but still with some spread.
I've considered raising the regulator setting from 135 bar to 145 bar and reducing the hammer blow to see if that helps, but what I'd be most interested in is adding a plenum. Has anyone done this? Is it possible?
I've followed many threads here and read entire posts about the BRK Bantam Sniper rifle, looking for information or, rather, a solution to a problem I'm experiencing with my rifle. This isn't a defect, but rather a characteristic of the rifle and its design. The first thing to clarify is that my rifle came from the factory firing at 39 joules, the regulator set at 135 bar, and it fires an 18gr JSB at 846 fps.
The problem I'm encountering is that I only get 45 stable shots (5 fps spread) at a velocity between 185 and 155 bar, which I understand is unexpected for a well-known regulator like the HUMA, and for a carbon tank that can be inflated to 220 bar according to the manufacturer and has a 500cc capacity. I understand that's very few stable shots. The total count is much higher, but with a spread of up to 20 fps. I should clarify that this is one of the first bolt-action models.
Reviewing the posts I've read here, some colleagues have played around with the hammer spring and pressure settings on the HUMA regulator, but without good results.
My conclusion at this point is that the lack of a plenum means that, at the moment of firing, there isn't enough regulated air available, and the regulator, with that pressure drop, lets air in at the same pressure as the tank, causing the shots to have a significant spread. This is most noticeable when the tank is between 225 and 185 bar pressure. After 185 bar, the subsequent shots stabilize somewhat, but still with some spread.
I've considered raising the regulator setting from 135 bar to 145 bar and reducing the hammer blow to see if that helps, but what I'd be most interested in is adding a plenum. Has anyone done this? Is it possible?