June 3rd, 2015

LR Primer Types Tested for Velocity, ES/SD, Group Size and More!

Target Shooter Magazine Laurie Holland Primer Comparison Test Magnetospeed
Click Photo to read full test results in Target Shooter Magazine.

If you shoot a .308 Win, or any cartridge that uses a Large Rifle (LR) primer, you should read an important new article by Laurie Holland in Target Shooter Magazine. Holland, a talented shooter from the UK, tested no less than sixteen (16) different large primer types using a custom F-TR target rifle shot from the bench. Laurie loaded .308 Win ammo* with 16 LR primer varieties and then tested for average velocity, ES/SD, and group size. This may be the most comprehensive and thorough LR primer test ever done. Here are the primer types tested:

CBC Magtech 9½
CCI 200 LR
CCI BR2 Match
CCI 250 Magnum
Federal 210
Federal 210M Match
Federal 215M Magnum Match
Fiocchi Large Rifle
Kynoch Large Rifle
Murom KVB-7 (PMC LR)
Norma Superflash LR
PMC LR Magnum
Remington 9½ LR
Remington 9½ M Magnum
Sellier & Bellot LR
Winchester WLR

LINK: READ Large Rifle Primer Test Complete (16 Primer Types)

Target Shooter Magazine Laurie Holland Primer Comparison Test Magnetospeed
Test Rig: Osprey Rifles-built F-TR rifle with Savage PTA action, 32″ Bartlein 1:12″-twist ‘Heavy Palma’ barrel, and Dolphin Gun Company modular stock with an F-Open/Benchrest fore-end.

Some of Laurie’s results may surprise you. For example, would you guess that Sellier & Bellot primers had the lowest ES, by a significant margin? And get this, among ALL the primers tested, Rem 9½M Magnum primers produced the lowest velocity, while Rem 9½ LR (non-magnum) primers yielded the highest velocity. (The total velocity spread for all primers was 35 fps). That’s counter-intuitive and it’s odd that Rems were at opposite ends of the speed spectrum among ALL primers tested.

“The rationale for doing side-by-side tests is to see what effect primer choice has on ballistics, i.e. average velocities and MV consistency. There are a great many views on the subject, a few based on tests (including primer flame photography) but most apparently hearsay.” — Laurie Holland

Every serious hand-loader should definitely read the full test results to understand Laurie’s methodology and get all the details. This is an important test, with significant findings. But if you can’t spare the time right now, here are some highlights below:

Primer with Lowest Velocity: Remington 9½ M Magnum (2780 fps)
Primer with Highest Velocity: Remington 9½ LR (2815 fps)
Primer with Lowest ES/SD: Sellier & Bellot LR (12/3.1 fps)
Primer with Highest ES/SD: Remington 9½ M Magnum (47/14.0 fps)
Primer with Smallest Group Size: Remington 9½ LR (0.43″ average, three 5-shot groups)
Primer with Biggest Group Size: CBC Magtech 9½ (0.7″ average, three 5-shot groups)

Editor’s Comment: Laurie shot three, 5-shot groups at 100 yards with each primer type. The average group size for the top six primers varied by only 0.10″ (0.43″ to 0.53″), so one can’t conclude that one type is much better than another. Total group size variance (from best to worst) was 0.27″.

Target Shooter Magazine Laurie Holland Primer Comparison Test Magnetospeed

“The biggest surprise to me … came from an elderly (at least 10 years) lot of Czech Sellier & Bellot standard caps with an ES of 12 and SD of 3.1 fps, way below those of the nearest competitor. By contrast to the Fiocchis, they were an almost slack fit in the cases and this may have contributed to their consistent performance.” — Laurie Holland

NOTE: Values in chart are based on 15-Shot strings. The ES/SD numbers will therefore be higher than is typical with five-shot strings.

Target Shooter Magazine Laurie Holland Primer Comparison Test Magnetospeed

Testing 16 primer types was a huge task — we commend Laurie for his hard work and thoroughness. This extensive test is an important contribution to the “knowledge base” of precision shooting. Laurie’s findings will doubtless influence many hand-loaders who hope to produce more consistent ammunition, or achieve better accuracy. Credit should also be given to Target Shooter Magazine for publishing the results. Well done gentlemen…


*Reloading method for Test Ammo: “Test batches consisted of 16 or 17 rounds for each primer, charges thrown by an RCBS ChargeMaster and checked on lab-quality electronic scales, adjusted if necessary to within ± 0.04gn, so any charge weight variation would be under 0.1 grain which equates here to 5 fps.”