I bought a Crosman 1701 about a month ago because I wanted a good PCP .177 pistol. The 1720 is no longer available but was my first choice. I live at 7126 ft altitude and co2/springer pistols are limited in the usability (velocity) at my altitude.
My preference is a regulated PCP so I realized that I was going to have to convert my 1701 to a 1720 if I wanted a decent shot count when I added a Huma regulator. Long story short I now have a 1720 (with the help of Crosman parts personnel) with a Huma regulator! A little costly to do it this way but after 3 months looking for a 1720 and not finding one this was the option I took.
I have a P-Rod that was my first PCP. I have modified the P-Rod over time, so I had an idea of the modifications I was going to initially do to the 1701/1720.
I knew I was going to open the TP but was not sure what size would be best so I went with a 0.080” TP as a starting size. My research indicates a TP of 0.087” to 0.092” may be the sweat spot so I also have ordered some drills that will step me between these sizes.
So far, I have tested the stock 1701 configuration, the 1701 configuration with 1720 12” LW barrel, the 1701 configuration with 0.080” TP/1720 12” LW barrel and 1720 regulated configuration with 0.080” TP. I did not do any hammer/TP tuning for these tests because I knew I was moving to a 1720 regulated configuration. This where I am today:
1701 converted to 1720 with larger TP, larger air reservoir (stock 1720) & Huma regulator
Pellet = 8.48gr QYS
Air reservoir = stock 1720 (larger air reservoir)
Barrel = 1720 LW (12”)
TP = 0.080” (increased from stock 1701 TP)
Huma regulator set at approximately 1740psi (120 bar)
Hammer stroke - stock 1701 (3 ½ turn up (CW) from full CCW)
Hammer spring - stock 1701 (1 ¼ turn up (CW) from full CCW)
Moderator = TKO
Starting fill pressure 3000psi
Ending fill pressure 1400psi
1701/1720 current configuration
Crosman 1701 converted to 1720
Huma Regulator
TP = 0.080”
Alchemy Airwerks Stainless Steel 2 Stage Trigger
TKO Moderator
DonnyFL moderator adapter
Steven Corcoran Forearm & Grip
Optisan CP 3-12x32P Scope
UTG Accushot Scope Rings
My preference is a regulated PCP so I realized that I was going to have to convert my 1701 to a 1720 if I wanted a decent shot count when I added a Huma regulator. Long story short I now have a 1720 (with the help of Crosman parts personnel) with a Huma regulator! A little costly to do it this way but after 3 months looking for a 1720 and not finding one this was the option I took.
I have a P-Rod that was my first PCP. I have modified the P-Rod over time, so I had an idea of the modifications I was going to initially do to the 1701/1720.
I knew I was going to open the TP but was not sure what size would be best so I went with a 0.080” TP as a starting size. My research indicates a TP of 0.087” to 0.092” may be the sweat spot so I also have ordered some drills that will step me between these sizes.
So far, I have tested the stock 1701 configuration, the 1701 configuration with 1720 12” LW barrel, the 1701 configuration with 0.080” TP/1720 12” LW barrel and 1720 regulated configuration with 0.080” TP. I did not do any hammer/TP tuning for these tests because I knew I was moving to a 1720 regulated configuration. This where I am today:
1701 converted to 1720 with larger TP, larger air reservoir (stock 1720) & Huma regulator
Pellet = 8.48gr QYS
Air reservoir = stock 1720 (larger air reservoir)
Barrel = 1720 LW (12”)
TP = 0.080” (increased from stock 1701 TP)
Huma regulator set at approximately 1740psi (120 bar)
Hammer stroke - stock 1701 (3 ½ turn up (CW) from full CCW)
Hammer spring - stock 1701 (1 ¼ turn up (CW) from full CCW)
Moderator = TKO
Starting fill pressure 3000psi
Ending fill pressure 1400psi
Shot 1 – 10 | Shot 11 – 20 | Shot 21 – 30 | Shot 31 – 40 |
703 | 701 | 701 | 701 |
709 | 702 | 705 | 697 |
701 | 702 | 704 | 694 |
703 | 704 | 707 | 689 |
701 | 705 | 702 | 684 |
701 | 707 | 705 | 677 |
699 | 705 | 706 | 675 |
704 | 705 | 705 | 670 |
706 | 702 | 705 | |
705 | 703 | 701 | |
1701/1720 current configuration
Crosman 1701 converted to 1720
Huma Regulator
TP = 0.080”
Alchemy Airwerks Stainless Steel 2 Stage Trigger
TKO Moderator
DonnyFL moderator adapter
Steven Corcoran Forearm & Grip
Optisan CP 3-12x32P Scope
UTG Accushot Scope Rings
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