Case weight variations

[hk940]

I am considering converting some loaded LC and TW crimped blanks into 300 BO.
I cut one each of LC and TW dumped powder and weighed both cases.
There was a difference of 3.1gr between each.
I normally weigh new cases (sorted by head stamp) on a bell curve.
What should be the cut off on the high and low end of the weights?
Some years ago I had worked up a load for my Rem. 700 .223 using Remington cases and found a very accurate combination.
A while later I loaded the same load into Federal cases and when I fired one it blew out the primer and flowed back over the extractor, trashing it
I had failed to weigh the Federal cases and found them to be 13-14gr heavier! meaning less capacity= higher pressure.
So I pulled all of the heads loaded in the Federal cases, but have not tried to work up a load in them.
My main question is if I make 300 BO cases out of mixed head stamps, What high/low weight variation in cases yield a decent load?

 

[FROGO207]

I would think that a regular LC and a LC blank of the same date that is trimmed to the same length would weigh the same. Not sure about the others. I do not make 300 BO brass yet.
I would trade or sell the loaded blanks for 223/5.56 brass as they are worth more than the common range brass. Seems like a less problematic solution to me.

 

[hk940]

Thanks for the reply, I got a trade deal from someone on another forum. 150 rounds of formed LC,converted to 300BO crimp removed for my 220 blanks!
Seems like a no brainer to me!

 

[AJC1]

I sorted 100 cases out of a batch of 138 remmington 308 cases into a .4 grain batch. If they are the same headstamp with a case that small, I would want a .5 grain spread or better.

 

[bullseye308]

I don’t load or shoot 300 but I do read a lot and in many places and from what I’ve seen, many guys just take LC 223 and cut it, form it, trim it, and load it with no problems. Most are just blasting away happily and not target shooting so there is that. There has been mention of some brands of brass needing the necks reamed as they were too thick, and one brand a guy had issues with had to be reamed and neck turned but he decided that was too much work and scrapped that brand and moved on.

 

[hk940]

I got my RCBS SB dies yesterday and have about 210 cut down LC and RP cases to form, and have about 155 converted LC cases on the way.
I should have something to keep me busy for a while!

 

[AzShooter1]

Your .5 grain difference will be plenty enough. Pays to keep them as close as possible and you will see the difference. You can go from an also ran to a season pro.