Annealing causing pressure increase

[SDHNTR]

Loaded up some .300wsm for the range today. Out of curiosity I loaded 10 3x fired and not annealed, and 10 3x fired but annealed. Wanted to see if I saw anything noticeable.

No noticeable difference in groups or ES. But the annealed group jumped 15-25 fps and made very slight ejector marks. ADG brass.

Why? Could I have changed neck tension that much? The neck diameter measurements were still the same. Is this telling me I overdid it? Or?

 

[ResearchinStuff]

how much difference was there on the shoulder bump between annealed and not annealed?

 

[Caseknife]

I would think that the maybe annealed cases were gripping the bullet tighter. Notice any difference in seating the bullets? Or with the annealed cases the brass was "stickier".

 

[SDHNTR]

how much difference was there on the shoulder bump between annealed and not annealed?

Zero difference. Was all out of the same batch of sized brass. I just grabbed 10 and sent thru the annealer.

 

[SDHNTR]

I would think that the maybe annealed cases were gripping the bullet tighter. Notice any difference in seating the bullets? Or with the annealed cases the brass was "stickier".

No noticeable difference in feel while seating.

 

[ResearchinStuff]

hm, i got nothing for ya then.

 

[SDHNTR]

hm, i got nothing for ya then.

Has me stumped too

 

[Jimbee]

Is there a purpose to annealing after resizing?

 

[SDHNTR]

Is there a purpose to annealing after resizing?

Oh yeah, I guess you’re right. I wouldn’t have done that, I don’t think. I must’ve annealed before sizing. That’s what I normally do. Nonetheless, shoulder bump would have been the same.

 

[Lawnboi]

Usually I anneal before sizing so take this for what it’s worth.

Did it feel like the case gripped the bullet more when seating? Neck tension can be more than interference fit, and after annealing especially on an amp that neck can have more grip. I usually combat this the same as I would with virgin brass and if a wet lube/ mandrel and dry tumble after sizing.

On most my brass, post annealing you can look in the neck and see the coloration/ grittiness change.

 

[Lawnboi]

Oh yeah, I guess you’re right. I wouldn’t have done that, I don’t think. I must’ve annealed before sizing. That’s what I normally do. Nonetheless, shoulder bump would have been the same.

Just saw this as well. If you’re not measuring, annealed cases will usually size more, due to less spring back. That’s pretty much why I anneal, so I don’t have to mess with my dies.

 

[Shortschaf]

Pressure is the same. Its the behavior of the brass that's different. Soft brass behaves more plastic than elastic.

On firing, brass instantly grows to the chamber size, steel chamber grows a tiny bit, and then both the steel chamber and brass relax back to size.

Anealled brass will relax less than hardened/elastic brass.
IE- it is swelled inside the chamber more than your unanealled brass, putting enough pressure on the bolt face to cause ejector marks.

A guess, you are probably overanealling a tish, or using hotter loads, or both.

 

[Cameron.25]

How are you annealing?

 

[JGRaider]

Zero difference. Was all out of the same batch of sized brass. I just grabbed 10 and sent thru the annealer.

What were your velocity differences between annealed and not?

 

[SDHNTR]

What were your velocity differences between annealed and not?

Not much, but see the OP

 

[SDHNTR]

How are you annealing?

Burstfire flame annealer.

 

[SDHNTR]

Just saw this as well. If you’re not measuring, annealed cases will usually size more, due to less spring back. That’s pretty much why I anneal, so I don’t have to mess with my dies.

I definitely measure. They were sized the same.

 

[Cameron.25]

Burstfire flame annealer.

I agree with the above reply, perhaps you over or under annealed. I used to have the same one and I've since upgraded to an AMP to take out all the guess work

 

[BULLBLASTER]

Shoulder bump would likely not be the same between annealed and non annealed brass. The annealed should bump more with the same die setting. Also i have noticed that the case necks distort slightly on annealing, so if you anneal after sizing the neck may be distorted.

 

[rayporter]

did you shoot the 20 rounds in a round robin or shoot all the not annealed first and the annealed second?