Winchester bass not alike

[upacreek]

I had a lilja barrel installed on my 7RM back in '13. The gun has made me happy and have routinely shot between 3/4 and 1 moa. I built the gun around 180 hybrids with 26" 1:9 twist and a break. At the time I bought 100 rds of new winchester brass solely for this gun. Hunting and reloading losses brought the number down to less than 85. So I bought another 100 winchester brass. Knowing new brass doesn't have the accuracy I was used to seeing with my neck sized brass, I wasn't concerned with ++moa impacts.
I just picked up a new barreled action a couple weeks ago so I had to take my trusty 7RM to shoot between shots with the new rifle. A few shots later I get a sticky bolt lift. Then several in a row. I check my ammo boxes and I am in some 2nd fired brass I bought a while back. Looking more closely the head stamp reads the same, but different. Once home I weighed them. The newer brass weighed 234.9 grains average. The older brass weighed 232.5 average.
My gut says go buy more brass and dispose of the older brass. But that puts my gun through all new bass and load development.

Am I crazy or should just ignore it? The rounds with stiff bolt lift shot 5 rounds in a 4" wide x 2" pattern@415yrds. The old brass loaded exactly the same way shot 5 rounds in a 2 1/2" wide x 1" pattern at the same target. Am I splitting hairs?

 

[MudRunner2005]

I'd recommend just getting you a couple boxes of new Nosler 7mmRM brass. ADG is coming out with 7mmRM brass this year, so that would be another good option, but it's not out yet. If you need brass now, the Nosler will treat you right. I've been shooting it for years, and it's already weight-sorted and prepped. Literally, ready to load out of the box.

https://www.midwayusa.com/product/630688/nosler-custom-brass

 

[MagnumManiac]

A 2gr difference in brass weight is neither here nor there in a 300WM sized cartridge.
I would suggest internal shape differences would be to blame for your inaccuracy.

What case prep do you do?

Winchester brass of old is not what it is today.
Who knows who Olin contracts there brass manufacturing to these days..............they sure as hell DON'T do it anymore, because QC is non-existent.

As to Norma brass over Nosler brass............I would take the Norma any day over Nosler. They are in fact the same cases, just Nosler weigh them and chamfer the necks. I have used both side by side, groups are identical, as is the weight.

All brass, even the same brand, differ somewhat lot to lot, there's no changing that. That's why for comp, a barrel gets a batch of brass and it stays with it for it's life. The barrel burns out before the brass does.

Cheers.

 

[zr600]

Yea was the old Winchester brass in the blue bag? And the new stuff in the red bag? If the old stuff is from the blue bag I would keep that. I use Winchester 243 brass and get great results they just have a little more work square primer pockets, deburr flash holes check length trim if needed and I load and go been good for me. Loose a pocket I just throw them away. It's fairly cheap brass.

 

[upacreek]

The brass I bought in '13 was new winchester brass, but I dont remember the color of the bag. I shoot 70.5gr Rotumbo under 180 hybrids sitting .010 off the lands. With a stiff bolt and bigger group size, I have decided to buy another 100 brass that match the latest brass and start again with load development. I use the gun for hunting under 600yrds, and target shooting to 1100yrds (so far). Thanks for the input, I needed to bounce this off some other people.

 

[zr600]

What's wrong with the old brass?

 

[upacreek]

I cant buy it any more and wanted more brass count. I have another 7RM that is a bone stock winchester black shadow. I can use the brass in it until I build that gun into something different.

 

[243winxb]

Compare loaded round neck diameters between the 2. The larger neck diameter was more accurate in my 243 win.

Could a larger neck increase pressure? Depends on chamber neck diameters.(hard bolt lift)

Neck sized brass may have something to do with hard bolt lift? Try bumping the shoulder with a FL die.

The weight of the brass would seem to mean little.

I would not switch brass between rifles. Are the belts on both lots of brass the same? Or does 1 allow more slop in the chamber? Any bulge in front of the belt?

 

[Mikecr]

I make sure I get enough brass/bullets/powder/primers, in-lot, for the life of a barrel(or two), and that the cartridge chosen allows that brass to last (no replacement cycles).
I even invest in excess stock to cull out the very best of it.
With this, I don't ever have to wonder about changes.

It might seem crazy, but it's always paid off.
All these folks complaining about shortages,, not me,, not in my plan.

 

[FURMAN]

Winchester brass has always been good to me but must be weight sorted regardless of lot#. I would suggest buying more than you need, weight sort, and sell what you do not need. I think I agree with Magnum but I think he got it backwards. Norma and Nosler are great but soft. I would take Nosler over Norma because they sort and prep.