I have a 250 Ackley Improved (aka a 250-3000 AI) Savage Model 99 with a 24" PacNor barrel. I found the rifle years ago, originally made in 300 Savage, with date of manufacture in the early 1950s. The stock was in decent shape but the barrel was defunct and the action needed some work. I sent to the rifle to the same person Savage (the company) recommends to repair/restore old Model 99s and, rather than put a new 250 Savage or 300 Savage barrel on it, I decided to follow P.O. Ackley's recommendations (from his long out-of-print book/treatises on cartridges, their design and performance, their ballistics, etc.) and put a new barrel on the rifle chambered in 250 Savage A.I. I have no regrets about this at all.
(Side Observation: The 250 Savage A.I., to my eyes and from what P.O. Ackley wrote in his books, looks like the original DNA for what became the 6.5 Creedmoor. I suspect the 6.5 Creedmoor is the 250 Savage AI necked up to 6.5mm (.264), with few, if any, alterations to the parent A.I. cartridge.)
The 250 Savage AI (with the 40-degree shoulder) is a remarkable cartridge. Its performance massively belies its small size and minimal powder consumption. While I was having the rifle restored and put together, I contacted various bullet manufacturing companies here in the U.S. in an effort to acquire load information for the cartridge. I hit gold when I talked with the kind people at Sierra Bullets. It turns out Sierra uses the 250 Savage AI as its test cartridge for .25 caliber bullets . . . and this is because the cartridge uses very little powder, feeds and performs with no issues (as long as the loads within it are sane), and produces outstanding performance.
From the Sierra Bullets PDF file the company sent to me, accumulated from a test rifle with a 24" barrel:
87g. Sierra BT or HPBT, 41.9g. RL 15, 3400 FPS muzzle velocity. // My rifle Model 99 (new PacNor 24" barrel) produced 3425-3440 FPS MV with both loads and groups under 1.5"
87g. Sierra BT or HPBT, 46.6g. H-414, 3400 FPS muzzle velocity. // I saw essentially the same velocities/accuracy when using 90g. Speer Spitzers.
100g. Sierra BT or Match King, 40.1g. Varget, 3200 FPS muzzle velocity. // 100g. Sierra BT or Match King, 41.0g. RL-15, 3200 FPS muzzle velocity.
My rifle produced 3250 FPS MV (average) with both 100g. loads listed here, about MOA accuracy with Varget and the Match Kings and 1.5" or less groups with Sierra BTs and Nosler Ballistic Tips. Both excellent loads for NE TX hogs.
117g. Sierra BT or Match King, 42.2g. H-4350, 2900 FPS muzzle velocity.
117g. Sierra BT or Match King, 42.3g. IMR4350, 2900 FPS muzzle velocity.
My rifle produced muzzle velocities ranging from 2940-2970 FPS with both 117g. loads and groups of 1.5" or less. The rifle reached 3000 FPS muzzle velocity with 115g. Nosler Ballistic Tips/Partitions and minimal tweaking of the respective 4350 loads up to 42.5g for each. No pressure or extraction problems noted and 1.5" groups or smaller.
Note:
WIth all loads listed above my Model 99 functioned flawlessly. There were no problems extracting any of the cases, and I have used the same cases (at this point) four to five times without issue, although I have to trim their length from time to time. Given the ballistics I'm seeing on my chronograph and the results on paper downrange, I have not tinkered or experimented with Sierra's recommendations with Sierra bullets.
I am confident I can produce 3000 FPS with the 117g. Sierra bullets without issues with pressure or case extraction--P.O. Ackley conducted extensive pressure torture tests on Model 99 actions and proclaimed them to be very strong--but see no reason to do so. A muzzle velocity of 2940-2970 FPS is ample in my book.
The case capacity on the 250 Savage AI is so small the cartridge quickly runs out of coal with bullet weights above 100g, although it is entirely reasonable to obtain 2800-2850 FPS muzzle velocities with 120g. bullets (I've done it with 120g. Nosler Partitions without issue). This is easier done, however, if the chamber on a given rifle permits seating a 120g. bullet so that it does not protrude into the case.
Regards,
Renaissance
Last edited by ARenaissanceGuy; 07/16/19.
