Gamo Delta Fox GT Whisper .177

Tested pellet number two today.
Also a very old tin of pellets I have had for ages. CZ, Diabolo Master. No weight given.
I used to shoot tins of these through my old Diana mod42 side lever at 12m, developing muscle memory for my .458Lott. They were super accurate in that rifle at 12m, even free hand. (I’ve just found out why!)
I measured the heads of 25 pellets, and… they were all identical!!! All 4.45mm. Unbelievable!
The “boxers” I measured yesterday had a 0.2mm variation. These had 0.0mm variation!!!

Anyway, shot a group of 10 on the left to “lead in” the barrel, then another group of 5 on the right for some extra leading in, then a final group of 10 in the center. All shot at 10m.
Pretty happy with that and I think it’s going to be rather hard to beat that… 🤔 But still got the JSB hades and exact to come!


All 25 measured the same 4.45mm!!!


Seems the “leading in” really works. First 10 shots on left, (first 5 all over, second 5 settled). Third 5 shots on the right. Then 10 in the center.

Edited by RangerPete - 27 Jun 2023 at 7:38pm

Should good enough for head size.
Prob be better sorting a tin out into head sizes first. It's supprising how much variation there can be and often the most common isn't the head size indicated. That way you can shoot groups of a particular size.
Relaxing way to pass a couple of hours.

So what was the head size it prefured.

I won this air rifle on a trade me auction, the title mentioned a “youth” rifle, so I bid on it for my 11year old son.
It retails for $270, I won it (brand new) for $115.

The box says it weights 2,9kgs, and it really is light. I believe my son could carry it around for a few hours. It is supposed to be a mid power rifle, and thus should be easy to cock, and yes, it is. I’ll test it’s velocity and power out put in due course.

Out of the box, it is small (for me being 6’4) but the right size for my son. The stock is a black polymer (plastic) ambidexteriois thumbhole, as most Gamos seem to be these days. The LOP and pistol grip are too small for me, but again right for my son. The barrel is covered with a plastic shroud from the breech/back sights all the way to the (whisper) “silencer”, so there is no exposed metal on the barrel or the breach at all.
Infact, the side plates of the breach, which are usually metal and show the serial number and caliber, are also plastic.
The open sights are very basic, but usable. Three tiny little fiber optic dots make up the sights (and I mean tiny) and the back sight is adjustable for both windage and elevation. The first time shooting it I was able to get a 15mm group on a small paper target at 10m, but my older eyes would DEFINATLY appreciate the addition of a scope.

The first thing I did was to clean the barrel. This rifle was manufactured in 2021, so although it is new, it has been in storage for about 2 years. A bunch of patches and some Hoppes no9 later and I was satisfied the barrel was clean. I tightened up the 3 stock screws, 2 of them needed about a quarter of a turn to nip them tight.

To “lead” in the barrel I used some old “boxer” pellets I had lying around and also used these first 20 pellets to set the open sights.
Starting at 5m to check that it was on the 14x14cm paper target I then moved back to 10m and adjusted the sights.

A The trigger on this rifle is absolutely HORRENDOUS!
There is simply no other way to describe it.
The first stage is ok, longish, but ok. The second stage is never ending, and is so heavy it almost required 2 fingers to pull through! Youth…? Hummmmm.
I will defiantly be doing the same “lengthen the little screw behind the trigger” mod that I have done on my Gamo CFR.
After suffering a few convulsions and forgetting to breathe numerous times because I was concentrating so hard on squeezing, I managed to get through the first 20 pellets.
A 15mm group had started to appear close to the center, which I was quite happy with, considering I could barely see the target 😂.

Step one done.
Step two, fit a scope, adjust trigger, keep sending pellets down range.