Gamo G-Challenger Review

Gamo G-Challenger Review

This week we have seen many of IWA’s latest offerings and my turn to play with new toys came in the form of the new Gamo G-Challenger. The G-Challenger is Gamos latest step into the world of competitive air rifle shooting, and they really have produced an outstanding rifle.
Opening the box, we can see that at its core, Gamo have utilised its CF under lever engine for this rifle, and rightfully so. The CFX, CFR and other variants are well known for their excellent accuracy, so what better place to start building your match grade gun. This foundation is further enhanced by the presence of Gamos IGT system, Smooth action trigger, adjustable but pad and check piece. The G-Challenger also comes standard with a set of dioptre sights and one of the best looking stocks I’ve seen on a Gamo rifle, all the bits that need to move do, the balance is near perfect and the grip sits comfortably in the hand.

Some Specifications for the geeks:

Total Length 1190mm
Total Height 170mm
Weight (no scope) 3.58kg
Stock Laser Engraved Beech
Bore 25mm
Stroke 100mm
Comprisable Air 196cm3
Cocking Lever length 400mm
Barrel Hammer Forged BSA Precision Barrel
Barrel Length 450mm
Barrel Width 15mm

The first thing we did was send some pellets over the chrony and we discovered something rather surprising. With the same engine as the CFR IGT one would expect to find similar results, yet the G-Challenger produced much slower speeds than the CFR IGT that it was tested alongside. I also noted much softer report and recoil from the G-Challenger than its plastic donned counterpart.

G-Challenger RWS Match

High 552fps
Low 537fps
Average 548fps

G-Challenger AA Field 8.4gr

High 481fps
Low 490fps
Average 484fps

The CFR IGT returned muzzle velocities around 720fps, 200fps faster than the G-Challenger.

Now comes the fun part, digging around inside to see what makes her tick. Stock off and in we go expecting to find the pile of muck standard in almost all middle of the range spring rifles. Much to my pleasant surprise the piston came out clean, the slightly dirty tissue shown at the bottom is the very first one used to wipe out the inside of the rifle. Only a thin film of grease was found around the piston and nothing in front of the seal. The piston seal was damaged during assembly due to the burs found on the inside of the rifle body, not nearly enough to cause the huge difference in muzzle velocity, however it was duly replaced. The burs were removed and the inside of the action was honed.

During the initial testing we found that the difference in cocking effort on both the G-Challenger and the CFR IGT was indiscernible, quite bizarre considering the tremendous lull in the expected velocity. Testing of both gas rams was needed.

This test was carried out on a drill press with a Load Cell bolted to the base and a digital display that gave a reading in KG’s. I tested both rams at 70mm and 100mm of their travel. The relaxed ram measured 250mm with the total comprisable length being 105mm of that. The normal stroke length of the rifle was measured at 100mm.

Both rams returned identical figures, the ram it seemed was not responsible for the variance in muzzle velocity either.

At 70mm – 55kg or roughly 540N
At 100mm-72kg or roughly 700N

It was at this point that I discovered the reason for the lower velocity and muted recoil. The rotary breech block that normally sports a 3mm transfer port had been changed to one with a transfer port of only 1.4mm. So less than half the normal transfer port diameter while still maintaining the enormous 25mm length found in all CF series Gamo Rifles. This little Modification has clearly made a tremendous difference in the way the rifle handles because the pistons travel is restricted by the speed at which air is allowed to pass through the transfer port. This slows the piston down resulting in softer recoil and much less noise.

After the discovery of the restricted transfer port, my concern immediately fell onto potential accuracy issues, so I put the rifle back together and went off to do some shooting at paper. It’s only fair to say at this point that the rifle was subjected to a standard lube tune, de-bur and general clean up before the test targets were shot, The barrel was cleaned and about 100 shots were fired to settle the innards. The accuracy testing was done indoors at 10m with the rifle rested on a bench, the rifle was fitted with a 4-16×50 Gamo Scope. A second Chrony string was shot to check velocities, the average speed had risen by 30fps as a result of the service.

The results speak for themselves, this laser guided gift from the heavens practically put pellet on pellet from the word go. The high quality match grade pellets from RWS did the best with a smallest 5 shot group size of just 8.15mm (3.65mm CTC) Air arms came in close second with Gamos coming up the rear, however still with respectable groups. I then did some shooting while sitting and standing and found The G Challenger to have no problem putting pellets where I wanted them although I have no doubt that a more competent shooter will achieve better results.

All things considered, The G Challenger is an amazing step up for Gamo, They have found a combination that encapsulates everything id want from an entry level competition gun. There absolutely will be one of these in my collection in the near future.


Author:St-John Salisbury