Others 1701P

[fderry]

Received my Crosman 1701P yesterday. Unboxed it and mounted a Williams open sight and a set of Steve Corcoran grips. Today I mounted a target at 10 yards and went to sight in the open sights when I realized my old eyes weren’t going to be able to use open sights! I had an Optisan CP 3-12x32P rifle scope on another PCP, so I borrowed it with its UTG rings and mounted it to the 1701P. Set scope at 6x, filled to 3000psi, sighted in the scope and shot 75 AA 10.3gr pellets. The ending pressure was approximately 1400psi (I ran out of my AA pellets at 75). I am very impressed with the accuracy and consistency for an unregulated pistol right out of the box.

For a Crosman out of the box trigger I was blown away. It has a nice first stage with a clear stop at the second stage with a crisp break for a total average pull of 13 ounces. I have a 1720 (1701 converted to 1720) and a Prod with the same trigger group but they required polishing/adjustment and still aren’t as nice as this trigger out of the box. In the past have paid tuners to get triggers this good!

Temp 62*
Barometer 23.06 inHg
Altitude 7126 ft
Shot count: 75
Low: 399 FPS
Hi: 433 FPS
Avg: 421 FPS
Spread: 34 FPS
STD Dev: 8.4 FPS

I am going to install some larger TPs to see how it performs at higher velocities. Also have a spare 1720 LW 12” barrel that I will install and test.

10 yard target

 

[PasadenaMike]

Absolutely amazing pistol. I have one with a Hawke red dot it’s stupid accurate

 

[fderry]

I installed a Prod TP (0.067”), my spare 1720 LW 12” barrel, Rowan Engineering air stripper and turned the hammer spring to 3 ½ turns from full CCW.
Hammer settings:
Hammer throw – 1 ¾ turns from full CCW
Hammer spring – 3 ½ turns from full CCW

I have looked for information on tuning a 1701/1720 on the internet and the best info on a 1720 tune is as follows:

nervoustrigger post on GTA Apr 5, 2015:
“I started by enlarging the transfer port to 0.094", then added three O-rings (-113 in 70A durometer) and managed to get a string of 26 shots inside of 4%. I then decided to try adding flat washers between the O-rings which is a technique that others have used. After playing around with the stroke adjustment and hammer spring preload, I ended up with a decent tune yielding 34 shots.

summary of the settings:
transfer port: 0.094"
Bstaley stack: 3x -113 O-rings (70A durometer) and 2x 0.054" thick washers (alternating O-ring and washers)
stock hammer spring
stroke: 2.0 turns from full CCW
hammer spring preload: 7.0 turns from full CCW”

This what I am using as a guide. Not sure I need the 12fpe he was going for but his post gives me a good starting point. I have the o-rings and washers he specified for the Bsaley modification, but haven’t installed them yet. Also, my TP is smaller than the one he used. My current tune is giving a max of 7.7fpe. Not sure I need more. If I stay at 7fpe - 8fpe, I will need to smooth out the shot curve.

Temp 58*
Barometer 23.43 inHg
Altitude 7126 ft
Benjaman .177 10.5gr
Shot count: 75
Low: 399 FPS
Hi: 573 FPS
Avg: 518 FPS
Spread: 174 FPS
STD Dev: 47.1 FPS
Starting pressure – 3000psi
Ending pressure – 600psi

5 Shot groups at 10 yards:

 

[fderry]

I added some Hill and Magnum parts to get more air tube volume and flow plus a B-Staley mod. Also restricted the air pressure that I tested at. More adjustment to come but I am happy with progress so far. The following is where the 1701 is today:

Crosman 1701
Crosman LW 12” Barrel
Hill High Volume Gauge Port
Hill Pistol Valve Cap
Magnum Airpower Custom Air Fill Adapter
DonnyFL 1/2”x20 Adapter
Rowan Engineering Air Stripper
B-Staley Mod (2) 3/4”x1/2”x1/8” rubber washers
Hammer stroke - 2 turns from full CCW
Hammer Spring - 3 turns from CCW

Pellet Benjamin 10.5gr
Altitude 7126ft
Temperature 58*
Barometer 23.30inHg
Shots 30
Spread 28fps
Average 588fps
Pressure 2600psi - 1600psi

573,FPS 7.7,FT Lbs
569,FPS 7.6,FT Lbs
578,FPS 7.8,FT Lbs
578,FPS 7.8,FT Lbs
583,FPS 7.9,FT Lbs
583,FPS 7.9,FT Lbs
589,FPS 8.1,FT Lbs
588,FPS 8.1,FT Lbs
592,FPS 8.2,FT Lbs
589,FPS 8.1,FT Lbs
589,FPS 8.1,FT Lbs
590,FPS 8.1,FT Lbs
594,FPS 8.2,FT Lbs
595,FPS 8.3,FT Lbs
595,FPS 8.3,FT Lbs
595,FPS 8.3,FT Lbs
597,FPS 8.3,FT Lbs
595,FPS 8.3,FT Lbs
595,FPS 8.3,FT Lbs
596,FPS 8.3,FT Lbs
590,FPS 8.1,FT Lbs
589,FPS 8.1,FT Lbs
592,FPS 8.2,FT Lbs
590,FPS 8.1,FT Lbs
590,FPS 8.1,FT Lbs
589,FPS 8.1,FT Lbs
587,FPS 8.0,FT Lbs
585,FPS 8.0,FT Lbs
581,FPS 7.9,FT Lbs
578,FPS 7.8,FT Lbs

 

[PasadenaMike]

Consistent