KosPilot wrote: ↑Tue Jun 04, 2024 3:51 am
Now that the GSP500 has been in circulation for a while, does anyone want to contribute with some experience based pros and cons vs the Pardini SP?
KosPilot
Here are my notes after 18 months of shooting the GSP500. The pistol is highly recomended and I think better than the Pardini in some small ways.
Thinking about getting the .32 barrel add-on in the future.
Walther GSP500 Notes
Trigger
Trigger setup, first stage 800g, second 220g small second stage roll off (trigger point 25-40 deg past let off point) with small transfer bar rattle (clearance for re-set).
Trigger set in lowest bar hole, using wide trigger shoe (side sharp edges removed ).
Trigger blade set full forward, flush with rear edge trigger bar.
Factory second stage spring OD 0.086”,Wire dia. 0.016”, length 0.235”
Factory second stage spring limited to 180g min. (min spring contact).
Spring changed to OD 0.080”, Wire Dia 0.012”, and length increased to 0.250”
This allows a good two to three turn spring contact and down to 100g second stage weight.
Dec 2023- new longer trigger shoe mfg. Alloy with 3.5mm shaft 3mm longer than factory allowing the grip spacer to be removed. Shoe now 10mm wide with slight flattened curve on lower leg.
Update July 2024 - Long alloy trigger cut down to be narrower at 7mm and contoured to finger.
Much improved feel for Std and Rapidfire.
Sights
Front sight, 3.2 mm, 3.6 mm & 3.9 mm
Rear sight, factory min 2 mm / max 4.5 mm
Insufficient rear opening for 3/1 rapid sight, rear sight will not allow the widest front sight to be used, light gap is too narrow. Throw back from using LP500 rear sight, will modify.
Modified rear to be min 3.6 mm / max 6 mm, good width – will allow up to 3/1 sight for Rapidfire.
Modifications
Front plate drilled for foresight hex screw access.
Sights added witness marks engraved and white paint.
Chamber/Feed ramp polished to high mirror finish.
Grip
Grip drilled for first stage weight access. (note hole is off set to centre-line)
Palm shelf rear edge rounded (3mm rad.).
Finger grooves cut bigger, angled slightly and higher up on tips, with little finger deeper.
Thumb rest lowered and flattened.
Trigger finger upper surface cut for clearance.
Aft ply filler added to add trigger finger length, rear grip trimmed to fit box.
(Note- removed after fitting new trigger shoe with longer rod.)
Stipple and Satin poly re-finish , 2 coats.
Weight/Spring Reference Data
Hole 7.18mm dia., 40.3 mm deep.
Barrel screw hole 7.18 mm dia. Depth above bolt 36.56 mm
Barrel weights, Tungsten 0.273” dia (6.93mm), 1.373” long (34.9mm),
Weight spring Wire Dia. 0.020” (0.5mm), 0.254” dia (6.4mm), overall free length 0.295” (7.5mm)
Compressed in hole 5.28 mm
Tension fitted to plate 280-300 g, fully compressed 520g.
4 coils, pitch 0.100” (2.5mm).
Ammo Testing
Chronograph Results - 15 round sample, Fastest to Slowest
Brand Average Extreme Spread Std Deviation
Geco Semi Auto 294 m/s 17.3 m/s 16.2 m/s
CCI Std Velocity 284.3 m/s 15.9 m/s 13.5 m/s
RWS Target Pistol 269.6 m/s 26.1 m/s 23.0 m/s
SK Std Plus 257.5 m/s 36.5 m/s 26.1 m/s
SK Pistol Match 251.0 m/s 28.3 m/s 26.5 m/s
Chrono results show 6-7 m/s faster for same ammo than Pardini (SK Std+ now safely passed)
Malfunctions
So far 600 rounds fired.
Malfunction fail to feed 4th round of RWS Target Pistol (4x) and CCI (1x), stove pipe with dent in case only half fed. Same as problem with Hammerli 280/SP20 believed to be the magazine feed if a round is over length, with nose catching on front face of magazine and dragging nose down.
I will modify an old SP20 magazine, slight vertical groove in front wall and test (which fit perfectly by the way).
After polish fail to feed last round Geco semi-auto (too hard cycle), rest OK.
Update March 2023 - 2000 fired no more malfunctions.
July 2023 now 5000rds, Dec 2023 now 10,000 rds. Only malfunctions failure to fire after hard strike with both new batch Eley Club and Sport, primer totally crushed.
Update June 2024, now approx, 18,000rounds. Only rare ammo fail to fire malfunctions (all brands).
Buffer requires replacement, centre of foam crumbling.
To Do
Play with extra barrel weights and also determine the best way around for weight/spring.
Stainless weights made and fitted, still waiting for tungsten weights.
Good argument about this on German forum. See Rapidfire testing.
Investigate possible interaction of safety with transfer bar feel during rapidfire. (done-nill).
Rapidfire Testing
Now testing as a rapidfire pistol to replace the Tesro TS22.
Best weight settings are Tungsten weights (springs front) in lower holes and S/Steel weights in
upper holes in reverse. (springs to rear).
Best ammo Sk Std + with short re-set trigger two stage.