Only change 1 thing at a time

[toallmy]

I should have remembered the rule and followed it . But what fun would that be .......
I have been working on cast in a 308 on and off over the last few months & slowly but steadily getting better results until today . Today my 100 yard groups look like my previous 300 yard groups . They were so bad I checked the rifle to make sure nothing had came apart .
I have been using coww's + tin cast NOE 311-180 FN , gc sages .15 copper checks , 35 gr of IMR 4350 , Winchester brass , win Lg rifle primers . Easily getting 2 - 2 1/2 inch groups at 100 yards around a 1/4 sheet of paper groups at 200 , and all on a sheet of notebook paper out to 300 yards . Loaded on a progressive press .
I know many here do much better , but I have been tickled with my meager achievements .
# 1 Well I cast me up a nice bunch of new boolits but I used my 50/50+ tin blend by mistake , not panicking I decided I'd give them a shot because I have already lube sized and checked them .
# 2 I decided to use some sample gas checks on some not perfect cast boolits . Just to see how they would shoot .
# 3 I started in on a batch of once fired 68 RA brass instead of the Winchester cases . I have been playing around with the powder charge and found the 35 gr charge in the Winchester brass was about as fast as I could push without the group's opening up .
Well I decided today I would zero the scope at a 100 yards , and set the caps on zero since I have been playing around at longer ranges trying to get a idea of my drop adjustment . I figured it would be a good time to shoot up some of the culled boolits ..
It didn't work out 10-12 rounds down range had me back in the house checking the rifle to make sure nothing came loose . Now I have to figure out what went wrong .
culled boolits , alloy , gas check , brass & or Powder charge

[Winger Ed.]

My first guess would be the culled boolits.
Unless your speed is way up there, I'd figure the alloy, checks, and brass is the least likely to be your issue.

Common wisdom seems to be very picky about the cast boolit being as perfect as possible for accuracy.

[toallmy]

I hope so , this is the first time I have tried culled boolits in a rifle .

[Green Frog]

Culled bullets are fine for warming up and fouling a barrel, but for accuracy testing? That's just asking for problems! By definition, defective bullets introduce a large possibility for inaccuracy, and until that possibility (or should I say probability?) of variation is eliminated you will be wasting time, powder, and primers.

Froggie

[44Blam]

With boolits, I generally only keep perfect boolits. You can just throw it back in the pot and try again.

[toallmy]

I pulled 10 of them and replaced the boolits with good no visible defect boolits , and everything worked out much better , but still not as good of groups . So I just pulled them all salvaging the components resized the brass necks with the primers still in the case . I will load a small bunch with slightly reduced charge to test again not knowing if the neck tension made a difference or pushing them a little harder opened the group's up .
Lessons learned the hard way are more easily remembered .......

[Ford SD]

I pulled 10 of them and replaced the boolits with good no visible defect boolits , and everything worked out much better , but still not as good of groups . So I just pulled them all salvaging the components resized the brass necks with the primers still in the case . I will load a small bunch with slightly reduced charge to test again not knowing if the neck tension made a difference or pushing them a little harder opened the group's up .
Lessons learned the hard way are more easily remembered .......

I am far from a expert on shooting cast or jacketed in rifles

I have been loading cast 308 for 30 plus years have stuck to a few powders ... sr 4759 is was a favorite in cast 308

I would think 4350 is too slow of a powder ..... and with your powder charge you are up there in velocity ??

change your powder and try a few

2400
unique
5744
4895

are a few of the ones I use in 308 / cast

I have shot 50 or so rounds at a single target and even the pulled/ called rounds would be covered by a hockey puck at 100,
you know the ones when the guy next to you lets off the first round with that loud muzzle brake

Ed Harris did a article on red dot in rifle rounds