I am shooting a 300 Weatherby and my group size has increased about an 1" at 100yds and in checking found some of the cases as long as 2.84 most at 2.83, so I haven't checked them before each reloading just trimmed them after a few reloadings to 2.815. So now I'll check them before each reloading but was wondering if the longer cases would effect my group size?
Does case length effect accuracy?
- Thread starter mnhunter2
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Hard telling not knowing what your chamber is cut for. As long as your bullet seating was consistent I would go with no
Sinclair makes chamber length gauges that allows you measure chamber
Pretty much this......I haven't seen a couple tho make a difference one way or another. Unless they are to long.
MagnumManiac
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Having run Weatherby chambers for years, I would say no, and trimming shorter also doesn't help.
Keeping brass long is what helps, keeping it square is also an advantage.
Cheers.
Keeping brass long is what helps, keeping it square is also an advantage.
Cheers.
Real interesting article over on Precision Rifle Blog where Cal Zant interviews the top PRS shooters. The guy he just did a multi[part interview is probably the best shooter in that discipline. I think it's the third part where he talks to the guy about his reloading process. Very interesting things he does and doesn't do when it comes to reloading. One segment deals with his take and experience with case trimming. His accuracy and consistency is nothing short of astonishing. When you read it and think of all the "status quo" in the reloading process it sure makes you think. I'm not saying I take it as reloading gospel, but sure makes you want to revisit your processes and your thoughts on your reloading process.
I'm assuming your talking about Austin Buschman. He's making me evaluate some of my steps for sure.
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Absolutely. Try to be consistent in your prep before loading and that includes case length. My process now is shoot, remove primer, clean, anneal, size, trim to length in that order. I know it seems anal but I've gotten to the point of ever measuring the bullet base to ogive. Found a few bad Bergers like that.
case length way short, will lead to big carbon ring hard as hell to get out.
One thing I would caution....He shoots a Dasher in probably a 20lb+ gun. They are easy to shoot and super forgiving on the tune.
He shoots 7k+ rounds a year this is where his skill set pays the bills not the shortcuts at the loading bench.
1000% agree PRS is so much about the shooter and less about the ammo. With the caveat it shoots well. He still says his ammo shoots .3-.4 which is good enough for me.
I was spending so much time reloading that I spent a bunch of money to speed it all up (progressive press, giraud, AT4) which I'm glad I did.
But then I'm spending so much time doing load dev, now I am working on streamlining that process to get me results I am happy with that allow me to just go shoot more. Also I don't do all steps for all ammo any more, depending what rifle it goes in and that rifles purpose it gets treated slightly differently.
QuietTexan
Well-Known Member
Increaed from what to what? Either way IMO no, a hundredth either way on case length isn't causing this. I agree with the above, unless you jammed a case mouth not likely a root cause.
Depending on if you went from bugholes to bad, or bad to worse it could be different things.
From bugholes to bad could be high temps pushed you out of tune, barrel fouled out, a scope screw worked loose (pretty common actually), or something relatively major like those are the more likely cause of a sudden massive change in group size.
If this is bad to worse could be you didn't have a great load to start with and you're just seeing the real size of the load. Had a few nice .5" groups but got occasional flyers, and now you got an "all-flyer" group aka found the real max dispersion of the load. Even great loads shoot a 1MOA group every now and again, it's a statistical likelihood that just has to be accepted. That's why I document all my groups, not just the pretty ones. Every once in a while you throw something that makes you want to puke, but you shout it again and it's back to normal
