The D54 .20 is numbered "27 Von 30" on the receiver and the barrel itself is a special run of L-W .20 barrels made in a run from Diana some years ago in anticipation of selling many in the then "new" .20 caliber.
I had never really heard of it until I was asked to try out Hector's Own .20 L-W D54 Diana with Traditions 3-10X black powder scope mounted in ZR mounts (first or second generation) and zeroed optically for the D48 "on wheels".
I had not bought ever a Diana air rifle in my life even though my dad had one in his childhood that reminded him of the first air rifle he and I got together on my birthday in December of 1969: a BSF .177 break barrel springer similar to today's HW30. I learned on that rifle.
Hector's .20 D54 had a balance and smoothness unusual to the times I would try out a sidelever Diana from the shelf of many sport rifle shops I've visited throughout the years.
The sidelever itself was something I had to get used to as another way of cocking an air rifle and if it felt like Hector's Own .20 then I wanted one and ordered it from him.
Tuning the rifle from Hector's Own JSB lubed pellets (standard not heavy) I specified tuning the D54 to JSB .20 Heavy Exact which really seems very little increase in weight but in reality I like the HEAVIER pellet in the D54 .20 configuration more than the light .20 D54 Hector has for himself.
I took this out for sight adjustment across a lake when the breeze was stirring in all directions to aim at 75 to 100 yards and while clicking the Traditions 3-10X scope UP I did some windage clicks realizing whatever the wind looked like over the lake the pellets were landing consistently as if drifted to the right 2" or so.
When I took out the Theoben .25 with the 20. something grain HN FTTs and started shooting across the lake at the target I found the gas ram to "be better" than a springer; but in retrospect what REALLY made the difference at ranges over 75 yards was the pellet caliber: .25.
In a Theoben gas ram the .25 pellet is more predictable than a .20 or .22 or .177 at 75 yards and above by the sheer ability to act like a projectile in motion that is not easily offended by breezes and winds. It's a hollow pellet capable of more than just being an air rifle pellet at close range. It stays stabilized better in wind. It is the better "varmint" rifle to use.
However, there are other reasons a .25 works better because of "dumping" energy faster in deformation. The .20 will go through anything out the other side without any teasing--but that .25, if it gets out the other side you see the thing is dead on the spot. No ricochet anywhere.
I had never really heard of it until I was asked to try out Hector's Own .20 L-W D54 Diana with Traditions 3-10X black powder scope mounted in ZR mounts (first or second generation) and zeroed optically for the D48 "on wheels".
I had not bought ever a Diana air rifle in my life even though my dad had one in his childhood that reminded him of the first air rifle he and I got together on my birthday in December of 1969: a BSF .177 break barrel springer similar to today's HW30. I learned on that rifle.
Hector's .20 D54 had a balance and smoothness unusual to the times I would try out a sidelever Diana from the shelf of many sport rifle shops I've visited throughout the years.
The sidelever itself was something I had to get used to as another way of cocking an air rifle and if it felt like Hector's Own .20 then I wanted one and ordered it from him.
Tuning the rifle from Hector's Own JSB lubed pellets (standard not heavy) I specified tuning the D54 to JSB .20 Heavy Exact which really seems very little increase in weight but in reality I like the HEAVIER pellet in the D54 .20 configuration more than the light .20 D54 Hector has for himself.
I took this out for sight adjustment across a lake when the breeze was stirring in all directions to aim at 75 to 100 yards and while clicking the Traditions 3-10X scope UP I did some windage clicks realizing whatever the wind looked like over the lake the pellets were landing consistently as if drifted to the right 2" or so.
When I took out the Theoben .25 with the 20. something grain HN FTTs and started shooting across the lake at the target I found the gas ram to "be better" than a springer; but in retrospect what REALLY made the difference at ranges over 75 yards was the pellet caliber: .25.
In a Theoben gas ram the .25 pellet is more predictable than a .20 or .22 or .177 at 75 yards and above by the sheer ability to act like a projectile in motion that is not easily offended by breezes and winds. It's a hollow pellet capable of more than just being an air rifle pellet at close range. It stays stabilized better in wind. It is the better "varmint" rifle to use.
However, there are other reasons a .25 works better because of "dumping" energy faster in deformation. The .20 will go through anything out the other side without any teasing--but that .25, if it gets out the other side you see the thing is dead on the spot. No ricochet anywhere.