I have bought two guns new a taurus tracker 44mag and taurus judge. In the tracker I had a fail to fire on one round of new Hornady ammo in double action I recocked and fired on the second try on the judge I had some paper 40 year old 410 birdshot and some from mid 90's about 14 years old plastic winchester 7 and half shot and new buck. I fired five rounds of buck and all rounds of the 40 year old stuff but had 3 fail to fire out of the 14 year old stuff recocked fired two but third never would fire. I do not believe it is the guns I get what I believe to be good strikes. I hear a lot of talk about hard primers. I know that my taurus 38 was fired new and after a hundred or so rounds no problems. These all have the transfer bar designs. I read where a couple of clips of the fire pin return spring helps or increase spring pressure with shim if no screws which mine has none on hammer spring. I also hear of a break in period on revolvers which makes since with anything mechanical will smooth out I believe. I have snap caped several times I hear from 500 to 1000 is good and I have noticed smoother action and trigger which could account for trimming the fire pin return spring might be similar to spring firing pin movement break in. While doing this my hand gets more used to pulling trigger so it may also seem easier but with exercise my pulls are stouter and seems hammer strike is getting harder hitting. I hear fast pulls that are not complete seem to cause lighter strikes as the transfer bar is not always well in place with a fast pulling. I am not sure on the judge with the ammo on 410 and its age but on the tracker I have heard some primers are harder on some ammo. I am thinking break in may help regardless of out of the box beliefs I saw where a man was told there was a break in period for taurus revolvers.