I bought my Gamo Big Cat last October, primarily as a knock around "truck gun." My thoughts were to have a light weight, durable rifle to carry around in the extra cab space in my Ranger. I was very impressed with the accuracy of the rifle in its stock form, but like many box stock Gamo rifles, it was a noisy, twangy shooter.
Since I was so impressed with the accuracy of the rifle I was determined to see just how good a Gamo can be with a professional level tune. I asked Gene of Air Gun Toys if he would do a top level tune on the Big Cat for me and he said send her out. I asked Gene to smooth out the rifle, get rid of the screen door grunch when the rifle was cocked, quiet the awful twang characteristic of a lot of high powered Gamos. We discussed power level, as I use this rifle as a pest bird shooter, I wanted power in the high 800s to low 900 fps. range. Gene agreed this was a reasonable set of expectations for this rifle. I shipped the Big Cat to Gene and he went to work for me. Gene did a lot of work on this inexpensive Gamo to get her shooting at her peak. He used a JM Tarantula spring, JM Apex seal, custom machined a new Delrin rear spring guide, made a new custom brass top hat, addressed the awful sloppy tollerance of the fit at the barrel bushing and receiver yoke, then did his magic on the receiver tube finish, applied the proper lubes and got her boxed up to send back to me.
Gene sent the Big Cat back to me priorty parcel post. Unfortunately, my post office decided that the rifle would be better cooling her heels on a shelf in the post office, rather than going to work on the local grackle population. I never received notice that the rifle had arrived and had to go to the post office yesterday and request the assistance of a nice gentleman working the back parcel shelves to find it languishing on a top shelf. In the post office's defense I have had a number of other guns arrive with no issues.
I brought the Big Cat home yesterday morning, unboxed it and mounted a Bushnell Banner 4-12 x 40 AO on it in Accushot two piece, four screw mounts. The mount and scope set up turned out to be a very nice fit. The scope sits as low as possible on the receiver and still allows the lens covers to be used.
I had the rifle sighted in with a short session, tried both RWS Super Domes and BSA Wolverines in the rifle as this had been its prefered fodder pre tune. Turns out the Big Cat is back to prefering the BSAs again.
As far as what the tune has done for the rifle, it cocks with a quiet smooth stroke, no more old screen door grunch. The firing cycle is quick and very strong, a hard, fast slap. The JM Trarantula spring is the higher power spring for Gamo "1000 fps" actions, so this puppy hits hard. Based on the data sheet Gene sent me for the Big Cat it was doing about 910 fps average pre tune, it now does about 945 fps average with a 9 fps SD, half the SD pre tune. With 8.3 - 8.4 gr pellets this puts the Big Cat at about 16.5 fpe, very impressive.
I only have about 50 shots through it so far, but I am very satisfied, very impressed with the performance and vastly improved shooting behavoir of this light, handy, powerful Gamo. The investment in the tune was worth every cent. Thank you Gene for your efforts on this rifle!
The tuned Big Cat got her first blood this morning. The Grackles have been coming back and are in mating season, noisy, raccous nonsense going on in the trees all over the neighborhood. They haven't given me a good shot in any of the trees in my yard this morning, but one of their favorite perches is a big 50' Maple in my neighbor's yard across the street. I decided to see what the Big Cat could do. The shot is about a 40 yard distance and the avian villian I selected was about 30' up in the tree. I was able to get a good kneeling rest, rifle in my hand on the rail of my front porch. 40 yds dialed in on the AO, 9x setting, slow squeeze of the GRT-III trigger, a loud POP, the BSA Wolverine found its mark and the avain gangster plummeted through the branches. (News Flash, had to pause a bit, I just caught another stinky grackle perched in the Maple in my front yard, 20 yd. shot, 25' feet up, POW, another dead grackle in the dust.........there's a theme here....).
Pics below of the Big Cat, the disassembled action with old and new parts (notice the cant in the old Gamo spring) :
