I am fortunate in having access to an up to 50 yd indoor that accepts airgun owners. I shoot primarily a Vet .25 ,a Royale in .22 and a Crossman 1701P. I have been using a very small zip tie as an empty chamber indicator but worry I could damage the breach o-ring or possibly the transfer port due to the hard irregular nature of the zip tie. Wondering what everyone else is using. Range masters are very versatile.