Smallbore accuracy

Border Barrels are embarking on an open-ended research program to get better accuracy out of .22 rimfire barrels. As the results come in, they will be posted here along with any conclusions we may have - tentative or otherwise.

The topics of research are listed below. They will usually not be complete and finished and the last update date is listed to the right of the topic.

Feedback boxes are provided on each topic page so you can make suggestions or comments. A feedback box is provide below where you can suggest new research topics. If your idea is taken up, due credit will be given, so make sure you leave a name and email address.

Rimfire Accuracy Research Topics:-

As Things Presently Stand - An historical perspective. (Updated 3rd November 2010)

Test Equipment (12th November 2010) A description of the equipment used for the testing

Velocity Dispersion (12th November 2010) A theoretical and experimental analysis of the vertical spread in groups due to bullet velocity variation

Group Statistics (22nd November 2010) The theory of Extreme Spread grouping, showing the best number of shots per group and the number of groups required to obtain a result within a given error.

Group Analysis (28nd November 2010) The practicalities of measuring Extreme Spread groups.

12 o'clock -vs- 6 o'clock firing pins (14th April 2011, updated 31st May 2011) Experimental results for velocities and pressures measured for both 12 o'clock and 6 o'clock firing pin positions.

The Vibrations of a Barrel Tuned for Positive Compensation (9th July 2011. Updated 20th October 2011) The principle of positive compensation is experimentally verified and this principle is used to tune a barrel by use of the of barrel vibrations as measured using a purpose built device.

Modelling vibrations on a rimfire barrel (23rd December 2011) This articles describes an attempt to create a theoretical model for the vibrations on a rifle barrel.