I just bought a brand new SAM-rod. I shoot A LOT of small varmints (i.e. mice), and occasionally rat or squirrel size ones. The semi-automatic function of a known/established domestic brand, particularly of the notoriety of the Marauder, was attractive to me for the frequent follow-up shots on running mice (hey, let’s face it, a mouse running at 40-50 yds in the woods/brush IS a challenge!). Right out of the box is a very visual and palpable look and feel of quality and solid function to the SAM-rod. Very well-made piece of gear. The rifle cycles and functions flawlessly for me, which many forums have posts as to being problematic for some. Now, it's precision is terrific... almost... until it isn't (i.e. it will put five+/- pellets in 3/8 +/- of an inch at 35 yards)... until the POI shifts.
After sending approximately 400 pellets down range now, what I have observed is the POI continues to shift all the way down through the pressure drop. It has 2 primary POI nodes it seems to be content with... and then it shifts considerably:
From 3,000 to roughly 2600 psi is one node, and from 2,600 to about 2,200 PSI is another node. From 3000 psi to 2000 PSI, it will shift well over an inch. Below that, it really starts getting squirrely (off the reg). While in a node it is a 1/4 to 1/2 MOA rifle. Which is maybe 8-10 shots. Then for another six to eight rounds, it will shift over an inch to settle into the next node. Then it will shoot 1/4 to 1/2 MOA again, over an inch away from the first node. Although only partially recorded, I mentally noted velocity will also shift accordingly in this process: low SD in the node, then a dropping fps trend, then low SD again in a node, then another continuously dropping fps trend. Then below 2200 it's a 1+ MOA group that continues to move more and more as would be expected off-the-Reg.
I've tried two glass scopes on it, with two different sets of rings, one being $100 scope and the other being a $400 scope, and one $1,300 thermal optic with integral mount. They all did the same thing. I did remove the barrel shroud and checked the torque on the barrel connection points and those seem to be fine. I did not remove the air stripper or anything in front of the barrel though.
Is there any simple thing to check for that these things are known to have that would cause what I'm experiencing, that wouldn't require a complete disassembly of the rifle? I'm very capable of doing that but, sadly, with all the adult responsibilities that I have, I really just don't have the desire to get into that.
I'm an engineer, a hobby machinist, and a general tinkerer. From the few articles and/or videos I've watched on fine-tuning these things, it's an involved disassembly and adjustment process that is still very subjective in a lot of cases, IMO. I will say there is a notable sense of quality in the construction and general feel of the rifle, in its favor. Much more robust and refined than the other pcps I have. It's too bad that either the design has flaws or the quality of this exception does, however.
I'll throw out this disclaimer for those of you who are disinterested in the Chinese rifles: I am not a fanboy of them, but I do have two, gen 1 Gauntlets, one in 25 caliber and one in 22, that have functioned flawlessly for thousands of rounds. I simply bought them for the price/value as my first foray into airguns. I was curious and not educated or experienced to know if I would like it. It is the honest truth, however, I can pick up either one of those rifles after having not shot it for a month, and it will still shoot 1/4- 1/2 MOA right where I left it. The only thing I have done to those two rifles is clean the barrels, light lube, replace one fill port, and adjust the triggers, except for the 25 where I did install a bigger tank.
For both rifles, I get 60 plus shots on the reg and they will print one-hole, non-shifting groups through that whole range, on the reg. The ninja Regulators that came with them are flawless and crazy easy to do anything with, although I haven't had to do a thing. The 22 caliber will shoot 1/4 - 1/2 MOA with the cheap Walmart, Crosman hollow point pellets that are $7 for 500, too.
Again, I'm not trying to be a fan-boy for any particular brand, or slam another, but only conveying a real customer experience with value/performance-points with one product versus another. The point that is particularly frustrating for me is that I decided to spend more than twice the amount of what I bought those Gauntlets for with the expectation I would experience significant quality and commensurate performance. I had already adjusted my expectations that the SAM, because of the nature of its semi-auto design, would probably not shoot as precisely as the bolt action Gauntlets. I was prepared to accept some deviation in performance, but the POI shift is well over an inch at 35 yards through the on-the-Reg range. What I got was significantly, significantly below expectations performance wise, and the cost/value is very upside down between these 2 products.
I'm at the point now, when I have free time, I just want to shoot. If I have to make some minor adjustment, then I'm good with that. Perhaps the air stripper is non-compliant in some manner... or that the barrel is somehow shifting. But... it is possible that something within the pressure system is at fault... bolt o-ring, regulator, ???. I'm really not keen on buying a new gun like this and having to start replacing part after part until I find the culprit just to achieve reasonable and unexceptional performance. I'm going to reach out to Benjamin/Crosman and discuss the issue. Failing success in that, a refund, or some type of better replacement.
I'm open to suggestions of the expertise of anyone who can weigh in on what might be at issue in the meantime. Is this the nature of the beast... live with it or leave it? Is there an assignable cause that can be remedied?
My gratitude for any insight.
mrw
After sending approximately 400 pellets down range now, what I have observed is the POI continues to shift all the way down through the pressure drop. It has 2 primary POI nodes it seems to be content with... and then it shifts considerably:
From 3,000 to roughly 2600 psi is one node, and from 2,600 to about 2,200 PSI is another node. From 3000 psi to 2000 PSI, it will shift well over an inch. Below that, it really starts getting squirrely (off the reg). While in a node it is a 1/4 to 1/2 MOA rifle. Which is maybe 8-10 shots. Then for another six to eight rounds, it will shift over an inch to settle into the next node. Then it will shoot 1/4 to 1/2 MOA again, over an inch away from the first node. Although only partially recorded, I mentally noted velocity will also shift accordingly in this process: low SD in the node, then a dropping fps trend, then low SD again in a node, then another continuously dropping fps trend. Then below 2200 it's a 1+ MOA group that continues to move more and more as would be expected off-the-Reg.
I've tried two glass scopes on it, with two different sets of rings, one being $100 scope and the other being a $400 scope, and one $1,300 thermal optic with integral mount. They all did the same thing. I did remove the barrel shroud and checked the torque on the barrel connection points and those seem to be fine. I did not remove the air stripper or anything in front of the barrel though.
Is there any simple thing to check for that these things are known to have that would cause what I'm experiencing, that wouldn't require a complete disassembly of the rifle? I'm very capable of doing that but, sadly, with all the adult responsibilities that I have, I really just don't have the desire to get into that.
I'm an engineer, a hobby machinist, and a general tinkerer. From the few articles and/or videos I've watched on fine-tuning these things, it's an involved disassembly and adjustment process that is still very subjective in a lot of cases, IMO. I will say there is a notable sense of quality in the construction and general feel of the rifle, in its favor. Much more robust and refined than the other pcps I have. It's too bad that either the design has flaws or the quality of this exception does, however.
I'll throw out this disclaimer for those of you who are disinterested in the Chinese rifles: I am not a fanboy of them, but I do have two, gen 1 Gauntlets, one in 25 caliber and one in 22, that have functioned flawlessly for thousands of rounds. I simply bought them for the price/value as my first foray into airguns. I was curious and not educated or experienced to know if I would like it. It is the honest truth, however, I can pick up either one of those rifles after having not shot it for a month, and it will still shoot 1/4- 1/2 MOA right where I left it. The only thing I have done to those two rifles is clean the barrels, light lube, replace one fill port, and adjust the triggers, except for the 25 where I did install a bigger tank.
For both rifles, I get 60 plus shots on the reg and they will print one-hole, non-shifting groups through that whole range, on the reg. The ninja Regulators that came with them are flawless and crazy easy to do anything with, although I haven't had to do a thing. The 22 caliber will shoot 1/4 - 1/2 MOA with the cheap Walmart, Crosman hollow point pellets that are $7 for 500, too.
Again, I'm not trying to be a fan-boy for any particular brand, or slam another, but only conveying a real customer experience with value/performance-points with one product versus another. The point that is particularly frustrating for me is that I decided to spend more than twice the amount of what I bought those Gauntlets for with the expectation I would experience significant quality and commensurate performance. I had already adjusted my expectations that the SAM, because of the nature of its semi-auto design, would probably not shoot as precisely as the bolt action Gauntlets. I was prepared to accept some deviation in performance, but the POI shift is well over an inch at 35 yards through the on-the-Reg range. What I got was significantly, significantly below expectations performance wise, and the cost/value is very upside down between these 2 products.
I'm at the point now, when I have free time, I just want to shoot. If I have to make some minor adjustment, then I'm good with that. Perhaps the air stripper is non-compliant in some manner... or that the barrel is somehow shifting. But... it is possible that something within the pressure system is at fault... bolt o-ring, regulator, ???. I'm really not keen on buying a new gun like this and having to start replacing part after part until I find the culprit just to achieve reasonable and unexceptional performance. I'm going to reach out to Benjamin/Crosman and discuss the issue. Failing success in that, a refund, or some type of better replacement.
I'm open to suggestions of the expertise of anyone who can weigh in on what might be at issue in the meantime. Is this the nature of the beast... live with it or leave it? Is there an assignable cause that can be remedied?
My gratitude for any insight.
mrw
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