I got my first PCP recently and although I am mechanically inclined I have made no adjustments yet. Not even the trigger which is somewhat of a miracle for me. When I first got my Gen 2 Marauder I tested it with several pellets and decided to start with the CPHP until I got the feel of the gun. They shot almost as well as the H and N FTT. I only pump it up to 2600 psi because when I did initial chrono tests that is where the velocity settled in. I was clocking the CPHP's at 860 fps. Today I did some shooting at 35 yards which is the distance I shoot when shooting sparrows off of my blue bird box. I had the rifle pumped up to 2500 fps and was shooting 1/2 to 3/4" groups off of a makeshift rest on top of my trash tote. All of a sudden it was like the God of accurate shooting touched me on the shoulder and the pellets were going through one hole. To be sure this was on the up and up I moved to a different spot on the target and they were going through a hole about 3/8" in diameter. Then it happened. A shot about 3/4" low, back to reality. Next shot was over an inch low so I looked at my pressure gauge on the gun and saw it was at 1800 psi. So here is my plan. I am going to pump the rifle up to 2600 psi and run pellets through the chrono and record velocity down to 2000psi which is probably as low as it was shooting accurately. Now here is where I am going to lean the expertise of the members. First, at this time I am not ready for a regulator although feel free to tell me how a regulator would help if you would like. I am just wondering if adjusting the hammer spring tension to reduce the pellet velocity to the speed that I get at 2000 psi will give me more shots. Right now I just want to see what kind of accuracy and how many shots I can I can get out of this rifle without spending any money on it. The other option I am considering is letting it like it is and only pumping to 2200 and shooting down to 2000 which would require me to make more trips to the Yong Heng but would open me up to a hand pump since only pumping to 2200. Please be nice as I am on the edge of the rabbit hole and have one foot on a banana peel. Thanks, Gary
PCP Newbie on the edge of the rabbit hole. Help Please.
- Thread starter profsrgary
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i'm no expert about the gen2 maurader, but you will need a shot string from 2500 psi to 1900 psi your sweet spot will present itself. as far as adjusting the hammer spring, some guns will yield extra shots , others will not. so tweek the hst lower and take a second shot string and compare. it's all trial and error in learning your gun. we all have to do this. so ,good luck and see what your gun tells you.
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Also if your just taking English sparrows at 35 yards maybe slow down your gun fps range; which I have found to be more accurate and yield a slightly higher shot count. When/if you start to adjust the spring tensions write down how many turns left or right you make and then chrono your gun and record the extreme spread. Its a process but should bring positive results. Good luck
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I'm not at all familiar with your rifle, but, Nice Going!
What you just did was found the 'sweet spot' in your 'shot curve'! Basically, that's the 'pressure range' you'll want to stay in..
Since we have max psi that drops to min, the pellets will always come out at relatively different psi / speeds..
With a given pellet, you'll find a pressure range where they shoot the best, and also the straightest..
With non regulated guns, it can be a bit trickier to figure out - Much easier with regulated - since the psi is relatively close each shot..
But back to yours.. Instead of maxing out the psi - because you Know the shots Will be less consistent..
You can fill / pump to a psi just a tad higher than your sweet spot.. I do that, then do a dry-fire to 'level things out'..
Then shoot.. And you'll find that when you're in that 'sweet spot', things will be the most accurate..
Above that / Under that - You'll notice more variation in points of impact. This is very normal, and all part of the game.
It's Great that you have a chronograph! That'll be a HUGE help! [I used to try to do all of this without one]
So.. You can either live with shooting in a certain curve range, or, do some tuning..
That's where hammer spring tension and/or regulator adjustments will bring you closer to the sweet spot and keep it there..
Again whey Regulated is such a nice feature to have.. Once dialed in, they'll stay there through Max to Min pressures
as long as the pressure doesn't drop below the set Min.
You're definitely on the right track!
Sam -
What you just did was found the 'sweet spot' in your 'shot curve'! Basically, that's the 'pressure range' you'll want to stay in..
Since we have max psi that drops to min, the pellets will always come out at relatively different psi / speeds..
With a given pellet, you'll find a pressure range where they shoot the best, and also the straightest..
With non regulated guns, it can be a bit trickier to figure out - Much easier with regulated - since the psi is relatively close each shot..
But back to yours.. Instead of maxing out the psi - because you Know the shots Will be less consistent..
You can fill / pump to a psi just a tad higher than your sweet spot.. I do that, then do a dry-fire to 'level things out'..
Then shoot.. And you'll find that when you're in that 'sweet spot', things will be the most accurate..
Above that / Under that - You'll notice more variation in points of impact. This is very normal, and all part of the game.
It's Great that you have a chronograph! That'll be a HUGE help! [I used to try to do all of this without one]
So.. You can either live with shooting in a certain curve range, or, do some tuning..
That's where hammer spring tension and/or regulator adjustments will bring you closer to the sweet spot and keep it there..
Again whey Regulated is such a nice feature to have.. Once dialed in, they'll stay there through Max to Min pressures
as long as the pressure doesn't drop below the set Min.
You're definitely on the right track!
Sam -
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I have a Gen2 Marauder (.177) that I have shooting at a fairly low power, around 13 ft lbs. Like you, I no longer pump up beyond 2600 psi or so since anything above that just gives me unpredictable POI results. From 2600 down to 2000 psi my shots are pretty consistent though not one-hole at 25 yards or beyond. I am considering a regulator as well, a HUMA or perhaps an Altaros, in an effort to eek out a bit more precision. I recently picked up a Maximus in .22 and am approaching the shot precision problem the way you are handling your Mrod's accuracy. I'm setting out a predetermined number of pellets, 20 or so, and pumping up between pellet sets. This gives me acceptable accuracy and I don't mind the pumping using a Hill 4-Stage hand pump. Guess I'm saying you aren't the only one approaching this issue in the way you describe. One thing I've considered is that a regulator operating at the relatively low pressures you have specified should have an acceptable lifespan so long as it is a quality unit. Tom Gaylord has pointed out that at some point a regulator, like all other pressurized parts on an airgun, will fail and need either repair or replacement. The caveat is that the higher the pressure differential handled by the regulator, the shorter the effective lifespan. Working at relatively modest airgun pressures, say between 2500 and 1500 psi, should/might result in a longer useful life for a decent regulator. At least, that's the theory I'm going with on my Marauder. I'll just stick with the "shoot some / pump some" method for the Maximus.
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I'm in the rabbit hole. Just put a regulator in the Gen 2. Finally found the sweet spot right at 1800 PSI for efficiency. Still need to test for accuracy, but pellets running about 815 fps or so. Now, to really tune it needs a lighter spring and hammer, then on and on with more bits and bobs to make it shoot like an Impact, which is impossible.
Finally decided the only addon will be the regulator. Hope it proves out to increase shot counts by 25% or a bit more and gets 40 shots per fill (.22 cal).
To keep out of the rabbit hole, or just stay to the side, decide what you want it to do, and design the mods for that purpose. You can spend as much on the Marauder as you want, and it's still a Marauder. If you want a high end gun, save and buy. It'll be cheaper and lots less frustrating in the end.
Finally decided the only addon will be the regulator. Hope it proves out to increase shot counts by 25% or a bit more and gets 40 shots per fill (.22 cal).
To keep out of the rabbit hole, or just stay to the side, decide what you want it to do, and design the mods for that purpose. You can spend as much on the Marauder as you want, and it's still a Marauder. If you want a high end gun, save and buy. It'll be cheaper and lots less frustrating in the end.
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Gary,
I would say listen to Ironlion269 he seems to know his airguns and has some great advice.
Good luck,
Jim
I would say listen to Ironlion269 he seems to know his airguns and has some great advice.
Good luck,
Jim
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Thanks for the advice guys. I am going to give things a try as soon as I get a chance and will post the chrony results. Very recently a member asked for advice on tuning a Gen 2 Mrod and a member suggested he install a regulator and open the port fully and give that a try to get acceptable velocity and shot count. If I slip on this banana peel I will let all know. OK, scratch that, when I slip into the rabbit hole.
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