New 6.5 Creedmoor brass headspace seems a little short

[Carey Farmer]

Prepping to load some practice rounds in my 6.5 Creedmoor target rifle with brand new brass. Checked brass length with a .400" comparator, and was surprised at how short the new brass is - about 0.007" shorter than fired brass from that same rifle. Checked my "go" gauge and the new brass is .005" shorter than a "go" gauge. Pulled a bullet from a Hornady factory round and the new brass is .006" shorter than the unfired Hornady case.

Should I be worried about this much extra chamber headspace compared to new brass length causing case - head separation?

Usually new, non-belted brass is at most a couple thousandths shorter than my fired brass.

 

[QuietTexan]

What brass is it?

 

[Carey Farmer]

ADG.

 

[Nimrodmar10]

What does the SAMMI speck say the brass should be

 

[nealm66]

That seems pretty normal to me with the 3 different creedmoors I load for (22, 6 and 6.5)

 

[nealm66]

I've found I've had to get 3 firings before they're tight if you're looking for 2k to bump to be sure.

 

[Carey Farmer]

Saami max chamber less saami min case length is 0.014".

 

[can1010]

have you tried checking with a smaller comparator .350-.375? with the .400 you might be getting a reading of the brass having a lower shoulder angle being new brass.

 

[Carey Farmer]

That seems pretty normal to me with the 3 different creedmoors I load for (22, 6 and 6.5)

Thanks nealm. I have a call in to ADG to ask them the same question.

 

[Carey Farmer]

have you tried checking with a smaller comparator .350-.375? with the .400 you might be getting a reading of the brass having a lower shoulder angle being new brass.

I don't have a smaller comparator, so haven't checked. But my sizing die hit bottom against the shell holder before the die contacted the case shoulder.

 

[can1010]

do you have anything to measure base to ogive on your loaded rounds? something in 8 mm or .338 will get your measurement closer to the neck/shoulder junction and if that is .005 or less then just load and fire away.

 

[Carey Farmer]

do you have anything to measure base to ogive on your loaded rounds? something in 8 mm or .338 will get your measurement closer to the neck/shoulder junction and if that is .005 or less then just load and fire away.

I haven't loaded any rounds with this brass yet. But yes I can measure base to ogive, and have measured oal with the bullet touching the lands using the Hornady tool.

A friend mentioned that I could "fire form" the cases by seating the bullets jammed a couple of thousandths for the first firing. But with 200 cases that's a lot of powder, primers, and bullets. Not sure I want to head down that path unless I really have to.

 

[can1010]

use the .338 in your hornady tool to measure the brass closer to the neck/shoulder, it is most likely a shoulder angle difference. fireforming that much brass will be costly and time consuming, if you go that route just do 20 or so at first and then use those and then everytime you go the range shoot a couple fireforming rounds to warm up and then put them away, by the time you use up the first 20 you will have plenty formed and ready to go brass

 

[Carey Farmer]

use the .338 in your hornady tool to measure the brass closer to the neck/shoulder, it is most likely a shoulder angle difference. fireforming that much brass will be costly and time consuming, if you go that route just do 20 or so at first and then use those and then everytime you go the range shoot a couple fireforming rounds to warm up and then put them away, by the time you use up the first 20 you will have plenty formed and ready to go brass

Gotcha. Using the Hornady 8 - 30 comparator (the biggest one in my set) the new ADG brass is 0.011" shorter than my fired brass. So no improvement in excess headspace from shoulder angle.

I'll post what ADG says.