Re: 80 gr Sierra's
I've never seen it. If anyone is at all, it would have to be a long barrel. 20 inch or shorter and I'd say don't waste time trying.
I've had 75gr JLKs shoot very well in a 9 twist bolt gun with a 24" barrel. A 75 is marginal in a 20" 9 twist AR though. Some say it will work but I never had good luck with it.
ET