Is this normal

[kyron]

I am new to reloading and I was very surprised today when I started cleaning up my brass after the first fire forming.

I used Remington 375 H&H brass necked it down in the 8mm rem mag die, then necked it down in the 7STW full length die. I trimmed, neck turned for consistency, debured and camfered. Then I loaded with a sub starting load of 7828 SSC. Topped with a Berger 180 VLD.

They all shot fine. But then after I de-primed them I measured them again they were shorter than before I fired them. By quite a bit. Some were as much as 0.020 inches shorter than before fire forming.

Is that normal?

 

[MudRunner2005]

I am new to reloading and I was very surprised today when I started cleaning up my brass after the first fire forming.

I used Remington 375 H&H brass necked it down in the 8mm rem mag die, then necked it down in the 7STW full length die. I trimmed, neck turned for consistency, debured and camfered. Then I loaded with a sub starting load of 7828 SSC. Topped with a Berger 180 VLD.

They all shot fine. But then after I de-primed them I measured them again they were shorter than before I fired them. By quite a bit. Some were as much as 0.020 inches shorter than before fire forming.

Is that normal?

Yes, that is normal.

 

[kyron]

OK. Thanks and I'll know to expect it on the next set of brass
gun)

 

[MudRunner2005]

OK. Thanks and I'll know to expect it on the next set of brass
gun)

Once you resize the necks down to 7mm, trim them .020" too long. Then check them again after fire-forming. And if they need trimming again, trim, chamfer, and deburr as usual.

I do this with my Ackley Improved cartridges. I trim the cases .020" too long before fire-forming, then once they form in the chamber, the cases are nearly perfect length and rarely need any adjusting.

 

[kyron]

yeah, I suspect I may have to junk most of the lot now but am going to try using them to see how bad the accuracy is with them being too short. This whole thing is new for me, rifle shooting, reloading, hunting...

So if a batch of bad brass slows me down a little bit while I am learning it is probably not a big deal.

 

[Lefty7mmstw]

If they are just a bit short use them anyway. They will grow after a firing or three...

When I blow out 375 h@h brass to 7mmstw I use a 338 as an intermediate step and lube well. It usually knocks down the crookedness to start with and I NEVER TRIM unless they are over length. I only trim after they are blown out as they may also need a bit of squaring....

I do caution you on over length brass-- check your chamber before you fire any over length brass... some will be fine and some will be to short causing a possibly severely crimped round after chambering and high pressure.

 

[4xforfun]

Too short does not mean poor accuracy. The only problem with short brass is the possability of acquiring a carbon ring. As long as the brass is all the same you are GTG.

I had a MAJOR BRAIN FART when prepping my Dasher brass for the 2011 IBS 1000 yard nationals and trimmed them down to 1.49 instead of 1.54. WOW...talk about stupid!! lightbulb But I AGGED 3.8 with that brass for the weekend!

So, again..just shoot em!!

Tod

 

[kyron]

Too short does not mean poor accuracy. The only problem with short brass is the possability of acquiring a carbon ring. As long as the brass is all the same you are GTG.

I had a MAJOR BRAIN FART when prepping my Dasher brass for the 2011 IBS 1000 yard nationals and trimmed them down to 1.49 instead of 1.54. WOW...talk about stupid!! lightbulb But I AGGED 3.8 with that brass for the weekend!

So, again..just shoot em!!

Tod

Wow. OK. Thanks to all for the help

 

[TackDriv3r]

They all shot fine. But then after I de-primed them I measured them again they were shorter than before I fired them. By quite a bit. Some were as much as 0.020 inches shorter than before fire forming.

Is that normal?

I normally resize / fireform a bulk of new brass and if they get short after first firing, just sort out the brass according to trim length before handloading to be more consistent when shooting 5 shot groups.