Confused: Brass/headspace question

[Bassnbow]

I have about 140 pieces of Nosler brass (280 AI). These were from factory loaded ammo I purchased from a friend that sold his 280. 100 had been loaded with 140gn ballistic tips and 40 were 140gn accubonds. They are all 1X fired from my 280 and now I am planning on reloading them. I know this is not the best procedure with mixed brass, but components what they are, I am making due with what I have. I was fortunately able to purchase 100 pieces of new Nosler brass, but it seems silly not to use these until I can get my hands on some of the Peterson brass.

I'm using Redding full length resizing die, adjusted to bump the shoulder back just a couple of thousandths. After resizing and getting ready to check trim length, I found the overall lengths are very different. Almost all were at or well above the recommended length of 2.525, so I figured no problem, I'll trim all to recommended length. Then I checked the length to the shoulder using the Hornady headspace comparing tool and found there was also a difference between them. Most were somewhere between 2.130 and 2.137. Is this .007 difference significant, seams like it is? I thought they should be the same since they were all shot in the same chamber, did they stretch differently, or maybe some stretched and some didn't? should I still trim to overall length and not worry about it until they have been fired a few more times?

I know ideally I probably shouldn't be loading brass from different lots, but with shortages I'm kind of stuck at this point. The rifle is primarily a hunting rifle and shoots very well, right around 1/2-5/8 with factory ammo and a little better with reloads (still actually fine tuning a load). At this point I have separated the brass based on this headspace measurement into 3 groups with each group being all within about .002 in size. Does this sound like best plan, or am a way over thinking this?

Any advice will be appreciated

 

[Carlos88]

The expander ball can actually cause lengthening of the shoulder when the ram is lowered. Found this out on my AR15 .223 Wylde.

 

[jimbires]

once fired brass is not fully expanded . if you have a neck sizing die use it for another couple reloads until the brass gets a little tight to chamber , then set up your die to bump your shoulder back about .002 . if the brass is not fully expanded it will have you chasing your tail trying to get a consistent shoulder bump . next thing would be proper sizing lube , what are you using ? I've went full circle here , I'm back to using a lube pad and RCBS oil .

 

[CBH Australia]

Watching with interest

 

[GLTaylor]

2 firings or more (if moderately loaded) is common before fully sized to your chamber.

 

[Deputy819]

if you have a neck sizing die use it for another couple reloads until the brass gets a little tight to chamber , then set up your die to bump your shoulder back about .002 .

^^^THIS^^^

 

[Bassnbow]

once fired brass is not fully expanded . if you have a neck sizing die use it for another couple reloads until the brass gets a little tight to chamber , then set up your die to bump your shoulder back about .002 . if the brass is not fully expanded it will have you chasing your tail trying to get a consistent shoulder bump . next thing would be proper sizing lube , what are you using ? I've went full circle here , I'm back to using a lube pad and RCBS oil .

Using the Hornady spray case lube

 

[nksmfamjp]

So, you have 100 new and 40 once fired brass? The once fired were from a buddy's gun?

Are they all sized now? How did you determine your shoulder bump? It sounds like you don't have any fired brass from your rifle? If you have fired brass from your rifle, what was CBTD measurement with the Hornady tool.

What rifle? Do you know how to pull the firing pin?

Have you tried a case wax? Like Imperial or…creedmoor sports. It revolutionizes sizing consistency….which is likely not your problem.

Do you anneal? Also probably not your problem.

 

[Bassnbow]

2 firings or more (if moderately loaded) is common before fully sized to your chamber.

Sounds like only being once fired is my biggest problem, that explains the inconsistency. I do have the neck sizing die also. The for the help

 

[Another Casual]

Once fired and with different loadings. I wouldn't worry about the difference. After a firing or two in your gun they will grow to fit the chamber and you'll be all set. In the meantime, if it fits it ships.

 

[Bassnbow]

So, you have 100 new and 40 once fired brass? The once fired were from a buddy's gun?

Are they all sized now? How did you determine your shoulder bump? It sounds like you don't have any fired brass from your rifle? If you have fired brass from your rifle, what was CBTD measurement with the Hornady tool.

What rifle? Do you know how to pull the firing pin?

No, I actually have 140 once fired from my rifle that were the original factory ammo and those are the ones I'm dealing with. I also have 100 new brass with some being fired, but nothing resized yet.

As far as sizing, I followed directions and with dies. First I measured multiple cases and found what I thought was largest of the bunch (shoulder length). Then with case in up position in press, screwed die down until touching. Then lowered case and screwed die in further until seeing it get bumped back. Now seeing these recommendations, I see I probably shouldn't have done it this way until being fired 2=3 times!

The rifle is a Christensen arm ridge line and yes I know how to remove firing pin.

 

[MagnumManiac]

If you have a discrepency in case to shoulder length on once fired brass, that tells me that some was shot with a milder load and have not fully expanded to the chamber. Not uncommon on factory loads.
As mentioned above, it may take 3 or more firings to get a case to fully fill the chamber.
An Ackley is also going to alter in headspace due to the nature of the 40° shoulder. It can take quite a few firings to fully form sharp corners which will appear differently on the comparator.
My 22-250AI Lapua brass is still rounded on the shoulder after 4 firings and I only just size the neck essentially in a Forster BR FL die with honed neck and bump with a body die when required. This particular rifle is my mid range F-class gun for 300-600 matches. It has a 1-7" twist 30" 1.250" straight barrel running 77g Nosler CC's.
The brass is stable and bump worthy only after 5 firings.
The same brass (Lapua) used in my standard 22-250 is stable by the third sizing and in both cases they are annealed after each firing. This is just to show you that shoulder angle halts expansion as it gets steeper in angle. I see this on quite a few improved cases, not just the AI version.

Cheers.

 

[Bassnbow]

If you have a discrepency in case to shoulder length on once fired brass, that tells me that some was shot with a milder load and have not fully expanded to the chamber. Not uncommon on factory loads.
As mentioned above, it may take 3 or more firings to get a case to fully fill the chamber.
An Ackley is also going to alter in headspace due to the nature of the 40° shoulder. It can take quite a few firings to fully form sharp corners which will appear differently on the comparator.
My 22-250AI Lapua brass is still rounded on the shoulder after 4 firings and I only just size the neck essentially in a Forster BR FL die with honed neck and bump with a body die when required. This particular rifle is my mid range F-class gun for 300-600 matches. It has a 1-7" twist 30" 1.250" straight barrel running 77g Nosler CC's.
The brass is stable and bump worthy only after 5 firings.
The same brass (Lapua) used in my standard 22-250 is stable by the third sizing and in both cases they are annealed after each firing. This is just to show you that shoulder angle halts expansion as it gets steeper in angle. I see this on quite a few improved cases, not just the AI version.

Cheers.

Great, sounds like I will just neck size for a while. Should I do this until brass starts to get a little snug when chambered?

 

[MagnumManiac]

As soon as the there is resistance closing the bolt, bump .001"-.002" and do ALL cases that are the same measurement. Some brass will still be moving more or less at this point.
You may not need the precision that I do for F-class, but it won't hurt to have some brass at different headspace lengths in a hunting rifle.
More important is internal volume, if you don't sort by volume, not weight, then it really won't matter if the brass has slightly differing headspace by a couple 'thou.

Cheers.