Using brass from another rifle in competition

[searcher]

We all know that chambers are different sizes and that can create problems, but not always. I'd anneal a sample batch of your brass, size it down with your regular die and try it. I've been in a jamb with .243 Winchester brass in the past and resorted to necking down once-fired Federal .308 brass (like I said - I was desperate). Anyway, I annealed after necking down, turned the necks and that stuff shot fantastic - as well as any Lapua brass or anything else. Sure, it won't last as long - and one can't put the pressure on it like the Lapua - but you do what you do to keep your rig running. If you have feeding or extraction issues, use a small base die and give it another go. If that doesn't work - that brass is not destined for your rifle.