John Milewski studies the calibre controversy from a vintage perspective
John Milewski investigates the ‘power myth’ of the .25 BSA Improved Model D
The BSA Improved Model D in No 3 bore or .25 calibre has almost a mythical status among collectors. Very few come to the market and these big bores can be difficult to source, irrespective of how much you are willing to spend on acquiring one. Stories abound of the power these BSAs are capable of achieving, so over the next two issues, we are going firstly to test a .25 and then compare our results with a contemporary .22 BSA. We will see how the big bore performs on the range and determine what caused its untimely demise after just a year of production.
When the BSA underlever was introduced in 1905, it was not until 1908 that a calibre other than .177 was offered, when the .25 came on to the market. Initially offered in an overall length of 43¾ inches, the standard length cylinder was not quite powerful enough to offer much other than a pronounced trajectory and power around 6 ft.lbs. This was soon remedied when a longer cylinder was fitted, which resulted in an increased overall length of 45¾ inches. This longer cylinder resulted in muzzle energy increasing to nearer 12 ft.lbs., although with no power limit in place until 1968, BSA adverts tended to make more of penetration than muzzle energy or velocity.
CHECK MUZZLE ENERGY
The .25 long cylindered BSA on test initially produced 7 ft.lbs. muzzle energy and a longer spring increased this to an energy level too near the legal limit of 12 ft.lbs. A slightly shorter spring, with very little pre-load reduced the energy to 10.8 ft.lbs. and resulted in less dieseling too. This demonstrates the importance of knowing your rifle’s muzzle energy, particularly when changing springs, in order to stay on the right side of the law. A lighter gauge spring also results in a smoother firing cycle and less recoil. Pellet choice is crucial with the .25 BSA because not all brands are suitable. Many modern .25 brands weigh in excess of 20 grains and are intended for FAC-rated air rifles, so they are too heavy for sub-12 ft.lbs. rifles and not the best performers. I used older Milbro Rhino, BSA Pylarm and Marksman pellets, all of which weigh in the region of 18-20 grains, and whilst all grouped together, every one of these brands produced occasional flyers, even at 6 yards. Marksman pellets are made on pre-war machinery by descendants of George Lincoln Jeffries, the original inventor of the BSA underlever, so I was willing this brand to shoot well subconsciously, which was perhaps a little unfair on the other brands. The Marksman pellets are certainly good enough for informal practice, but the odd pellet does fly off at a tangent, thereby expanding group size.
THE PERFECT PELLET
I wanted to obtain consistently accurate groups before adjusting the sights and there was one more brand left to try. I had less than a tin of .25 H&N Field Target Trophy pellets left over from a previous test, and was astounded at the improvement in accuracy when these 20-grain pellets were tested from the standing position. All four of my five-shot strings landed within an inch at 6
“the .25 comes into its own, because the heavy pellet hits its target with far more clout”
yards and the pellets seemed to recoil less than the other brands, too.
After adjusting the rifle’s sights, I found my groups were forming around ¾” above my point of aim at 6 yards, when the sights were set as low as they would go. This increased to an inch at 10 yards and dropped to point of aim at around 20 yards. From this, we can see the .25 has a trajectory, which is a lot more pronounced than the .22 BSA from the same era. The .22 pellets are lighter at around 14-15 grains and a rifle producing around 11 ft.lbs. will zero down to point of aim at 6 yards.
RAW HITTING POWER
So much for accuracy. Now let’s look at what happens when a target is hit with the 20 grain .25 pellet. I placed tins filled with water at a distance of 15 yards and the .25 launched a tin into the air along with the water with a resounding wallop. This is where the .25 comes into its own because the heavy pellet hits its target with far more clout than a lighter .22. The No 2 bore also launched a tin into the air, but it was clear to see the .22 H&N FTT pellets were going straight through the water-filled tin with plenty of energy to spare.
I found the .25 an accurate rifle, which will group well, but the trajectory is noticeably pronounced, so it is vital to know the distance to your target and know where to aim. Neither is impossible and in actuality, a lot of fun to set up because it gives you an excuse to shoot the .25! Next month, we’ll compare the performance of a near identical BSA, but in .22 calibre. I
There are far fewer .25 pellet options that .177 or .22, but one of these should fit the bill.
Pre-WW1 BSA Adder pellets in .177, .22 and .25. The .25 is believed to be an Adder pellet and was kindly given to the author by John Atkins.
Lincoln Jeffries offered rifles in .25, too, as this page from a C.1908 catalogue attests. This water-filled tin was launched into the air by the force of the .25 pellet’s impact.
This is what all BSA collectors look for – a prominent 3, designating the big bore! The shotgun-style, straight-hand stock on the .25 resulted in a fast target acquisition.
‘Bessie’ might not be in the best condition, but she is a real rarity.
The .25 calibre BSAs can mostly be found with serial numbers in the 19000 to 23000 range, but others do exist. Note the numeral 3 signifying the calibre.