Got an R2a as well, avoid but better than the other polish R3 thats worthless last 9 out of 9 times checked.

Have to put on low sensitivity just fails to register or give wild readings.
Need controlled light to give an accurate reading LED wont do it and wont work in lower light. Bright light reads way fast. Point is no ones going to be able to tell whats right or wrong blaming other things, same with R3. Couple of times have taken the R2a outdoors it has given readings in the ball park, muzzle 9" back.
Its only salvation is the higher gate and portability.