case/neck hardness - can it cause failure to seal (lack of obturation)?

bewsher500

Well-Known Member
I have some Lapua .243 cases which to my knowledge have only been fired between 2-3 times.

recently I have found that I have some cases that I am firing for the first time are showing soot much further back towards the head than I would expect.

The only thing I can think of is that they were fired considerably more than the "once fired" when I got them!

It doesnt seem to make any difference if it is a low, medium or hot load.
I have some test loads from the other day which I knew would probably be too hot and sure enough they are just beginning to show pressure signs but the neck is sooty almost down to the shoulder.

Would annealing make a difference or should I junk them and start fresh?
 
If you have soot back past the shoulder and onto the case body that means the whole case is not sealing properly, which is usually a sign of to low a powder charge.
Are you using a Lee collet die?

Ian.
 
Unless you are using very light loads, and you are getting soot past the shoulder, toss the brass. Annealing back that far under DIY conditions can be risky.

Collet dies won't cause that condition. Even if a neck is barely holding onto a bullet, the pressure should seal the chamber unless the loads are light. I have deliberately colleted "light" on my .222 and let the leade seat the bullet into the case for target shooting. These rounds always obturated enough to seal the case.~Muir
 
its not consistent, that is my problem.
The loads have been a variety of 75 through 100gr .243
I ran three shots of 43.6gr N160 under Berger 90gn BTBT, which is far from light!, case heads showed some light pressure signs, soot mark went down neck and about 1/3 of the shoulder.

Others are 1/3 down the neck and look normal.
some have gone past the shoulder.

weird thing is the groups are fine. 1/2" 100yd group with 100gr Interlocks, 3/4" 130yd group with 75gn Vmax!

All brass has been neck sized only (by me at least!), chambers fine, ejects fine.
Cases look normal, no signs of mass firings, headstamp is clear and lettering deep.



I suppose annealing would be worth a shot to at least give them one last chance before scrapping them!
 
if you anneal with tempilaq paint 650-750 deg f you cant mess up the case ,its better to do it on the machine i have the benchsoarse best investment i made to my long range set up as you get great consistency from case to case down to the micro second
i have compition brass fired nearly 20 times on full power loads and i get .250 moa vertical or better at 1000yds ,brass degrades and work hardens after about 3-4 reloads even in a custom chamber with good dies ,so a factory chamber has a lot more room to move and size down
for a stalking rifle you wont notice it at 100 mtrs but at long range you will ,but its worth annealing in my veiw saves a bit of money for you ,or if you have deep pockets just bin the brass and buy new
 
if you anneal with tempilaq paint 650-750 deg f you cant mess up the case ,
I have thought about doing it myself but the tempilaq comes in 50deg increments. do I go with 650, 700 or 750?
or I could just send them to you :)!

The other option is I bite the bullet, so to speak and bin them! I do have access to some (true) once fired norma from a friend but probably would get them for a few months!
dont really want to drop £100 on new brass
 
750 deg f is what i have used for years done it manualy with great success ,but if you want me to do it on the machine its £10 a 100cases plus delivery but they will be annealed properly,or if your passing dundee drop them off
 
i have the same machine and it was £600 +gas and fittings it aint cheep to set up ,but for me its worth every penny
 
Cripes have you seen his prices? You can buy once fired for that.
You cant buy once fired Lapua brass for £18 per 100 mate,plus do you actually know they have been once fired also they will need annealing at some point.If using quality brass its well worth the small fee,if using cheap brass just bin it and buy new.
The killer is the postage charge of £5 but thats the post offices fault hence why I went and had them done while I waited.
The machine is the best part of £600 with torches and pipes ( I looked into buying one) so you need to do a lot of brass to get your money back,3300 pieces to be precise that a lot of annealing so buying one isnt really viable for me.
Anyway it was a cracking service which saved me money and will be using again after another 3 or 4 times fired.
 
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You cant buy once fired Lapua brass for £18 per 100 mate,plus do you actually know they have been once fired also they will need annealing at some point.If using quality brass its well worth the small fee,if using cheap brass just bin it and buy new.
The killer is the postage charge of £5 but thats the post offices fault hence why I went and had them done while I waited.
The machine is the best part of £600 with torches and pipes ( I looked into buying one) so you need to do a lot of brass to get your money back,3300 pieces to be precise that a lot of annealing so buying one isnt really viable for me.
Anyway it was a cracking service which saved me money and will be using again after another 3 or 4 times fired.

Well, mate, I don't need to use lapua brass.
I know exactly what the bench source machine costs.
Fortunately I built my own annealing machine and it works fine, it does not cost anywhere near £18 to anneal 100 cases.
(unless, of course, you want someone else to pay for your machine...)
But then I do not offer an annealing service - I only do for friends!

The guy who does this 'service' is well known on other forums - he has well proven his 'worth'. Nuff said
 
Well, mate, I don't need to use lapua brass.
I know exactly what the bench source machine costs.
Fortunately I built my own annealing machine and it works fine, it does not cost anywhere near £18 to anneal 100 cases.
(unless, of course, you want someone else to pay for your machine...)
But then I do not offer an annealing service - I only do for friends!

The guy who does this 'service' is well known on other forums - he has well proven his 'worth'. Nuff said
its a service like any other you pay for I dont suspose for one instance you work for free,as I said it saved me £100 in brass so well worth it,
as to the guy who did it,seems a very nice chap and was very helpfull,take as you find,thats my motto.
 
I had similar problems in my 6.5x55 with sooting down the case and as has been mentioned previous, this was caused by low pressure. The problem went away when I increased the charge or when I sat the bullet deeper in the case reducing the OAL. I see you mention that the charge is not a light one so I would have a go seating the bullets deeper to see if that makes a difference.
 
I had similar problems in my 6.5x55 with sooting down the case and as has been mentioned previous, this was caused by low pressure. The problem went away when I increased the charge or when I sat the bullet deeper in the case reducing the OAL. I see you mention that the charge is not a light one so I would have a go seating the bullets deeper to see if that makes a difference.
Well most of my bullets are seated to the crimp cannulure rather than long, land reaching seats.
pretty sure it is not pressure as some of the higher charges had pressure signs AND sooty shoulders
 
Work hardened necks usually show them selves as splits and cracks after firing. I have only had "sooty" case necks from soft loads, however there maybe another reason but i doubt it is brittle brass.
 
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