"I owned a Brocock Bantam .25 before but can't say I was impressed". My .22 Brocock Bamtan HILite (carbon-bottle model) being definitely among my top 3 finalists in any oft-asked hypothetical "If you could own only ONE air rifle" query, I feel compelled to speculate on the reasons for my and DB's vastly different opinions of the Brocock Bantam. Unless I'm mistaken, the difference simply boils down to caliber choice(s).
No doubt each airgun power-plant performs better in certain caliber(s) than others. More specifically, as pertains equations involving the elements of power produced, efficiency (shot-count), and accuracy. And each of those elements are affected by projectile choices in each caliber.
The HiLite's equation sensitivity relates to it's Sling-shot firing system. However, that feature is one of the primary reasons I love my HiLite SO much...
in 22 caliber. That stated, the Sling-shot system is probably also the primary reason DB is... correction,
was not impressed with his .25 HiLite.
Before purchasing my HiLite, I invested a fair amount of due diligence investigating the performance differences between the caliber choices (.177, .22 and .25). I came to the conclusion that .22 performed more than little better than the other calibers,
especially .25. Be that performance difference due to the Sling-shot system or other design idiosyncrasies in the HiLite, the HiLite not only didn't have guts enough to achieve impressive velocities in .25 caliber, but from what I could tell, .25 caliber shot-count pretty much sucked.
However, assuming 30 foot-pounds of muzzle energy in .22 caliber satisfies the buyer's want/needs, the Sling-shot system impresses me enough to not only repeat myself (again) in saying I prefer the SS system to regulators, but to now own THREE Sling-shot guns.
I've successfully increased the power of my .22 HiLite and .22 Daystate Wolverine to 31-32 foot-pounds with simple techniques, while still maintaining acceptable shot-count. However, more extreme gunsmithing techniques increasing my .177 HiLite from 18 up to 23 foot-pounds affected it's shot-count more drastically. Interestingly, albeit unrelated to this thread, my .177 Bantam is more accurate shooting 10.3 JSBs at 22-23 foot-pounds than at 18 foot-pounds (or 13.43 JSBs at 23 FP). That being the case, I accept the reduced shot-count as the price paid to transform my .177 HiLite into a keeper. I can live with 3/4" groups at 50 yards with 10.3 JSbs at 1000 FPS; but can't live with 1" groups at 50 with 10.3s at 880 FPS.
Lil' Laser-
My research suggests .25 caliber the worst choice in Brocock Bantam HiLites from velocity and shot-count perspectives. From what I've read, .25 HiLites neither produce good velocities (for what most folks want in a .25), nor acceptable shot-counts (for what most folks expect in a bottle gun).
In my opinion, based on what I've read and experienced, the Brocock/ Daystate Sling-shot firing system really "hits the spot" in 30 foot-pound .22 caliber, does pretty well in 18 foot-pound .177, but misses the spot in .25.
18.1 grain JSB, 250 BAR fill, 54 shot powerband- Low= 871, Hi= 892, ES= 21, SD= 3, Average= 884 FPS/31.5 Foot Pounds