Applied Ballistics Tests Reveal BCs of 50 Rimfire Ammo Types

Photo shows Bryan Litz (on right) and tester Mitchell Fitzpatrick. Bryan said: “Only 2,445 rounds to go! We’re testing over 50 ammo types in five different twist barrels… science can be exhausting!”

Do you know the actual BC (Ballistic Coefficient) of your rimfire ammunition? Well Applied Ballistics has the data, thanks to a comprehensive, marathon ammo testing session. Some years back, in an effort to determine the “real world” BCs of various rimfire ammo types, Bryan Litz and his team at Applied Ballistics did an extraordinary, in-depth shooting test. Litz and company tested over fifty types of .22 LR ammo, using five different twist-rate barrels. This was one of the most comprehensive and through rimfire ammo tests ever done.

Bryan tolds us: “We tested many types of .22 rimfire ammo for the 2nd Edition of the Ballistic Performance of Rifle Bullets book. We used a pair of Oehler chronographs to measure velocity at the muzzle (MV) and velocity at 100 yards.” With these numbers (average and SD) Bryan can calculate G1 BCs for all the 50+ types of rimfire ammo. What’s more, because every sample is shot through five different barrels (each with a different twist rate) Bryan can also determine how velocity is affected by twist rate.

The tests are primarily to determine velocities for BC calculations — this was not an accuracy test. Bryan explains: “Our tests are not really looking at accuracy, mainly because that’s so subjective to different rifles. Our testing is primarily focused on measuring the BC of rimfire rounds from different twist-rate barrels. The MVs and BCs from the different twist test barrels was then published by Applied Ballistics in print books. Bryan Litz told us: “The .22 LR Rimfire data was originally published in Ballistic Performance of Rifle Bullets, 2nd Edition, which is now out of print. The 3rd Edition of that book doesn’t have rimfire data. The rimfire testing results and data were re-published in Modern Advancements in Long Range Shooting – Volume II (along with many other topics).

Bringing Science to the Rimfire World
Bryan’s goal with this project was to increase the rimfire knowledge base: “We hope to give the world of .22 LR rimfire a good dose of science. How is the BC of .22 rimfire ammo affected by barrel twist? Do subsonic rounds have more consistent BCs than supersonic or transonic rounds? What brands have the highest BCs? What brands have the most consistent MVs?”

Data from two Oehler chronographs is recorded in a computer. Ammo samples were tested in five (5) different barrels (of varying twist rates). Give credit to Dane Hobbs who supplied a test rifle, multiple barrels, and most of the ammo types for the test.

.22 LR at 300 Yards?
Bryan also conducted some longer range rimfire tests. His interesting findings have appeared in the Modern Advancements in Long Range Shooting book series. Bryan notes: “While .22 rimfire isn’t typically considered ‘long range’, we were able to consistently hit a two-MOA steel target at 300 yards with the trajectory predicted by AB software and the measured BC of some standard .22 LR rimfire ammo. The info we’’re generating may make it possible to push the range of target engagement for a round that’s not seen much advancement in many decades.”