Brass not fire forming

[DLCrocket]

In the past, I've fire formed 500 .243 winchester cases in my Savage 12FV 243 AI with every one forming to satisfaction. Recently I purchased 100 pieces of new Srarline brass and had three or four rounds that after three firings had very rounded, unformed shoulders. (See case on right) Wondering if anyone has had this issue. Thanks.

 

[fkimble@charter.net]

Too light a load? Using slow powder? Using light weight bullets? Excessive headspace? Not enough pressure!

Frank

 

[Fuj]

Brass may have been extra thick in that area, or missed getting annealed.

 

[Gary in MD]

You're probably going to have to lean on the powder measure a little harder.

 

[Bill K]

A few pieces of the new brass would appear to have been slightly harder in the making of it. Anneal them and run them back through your sizing die, the try another fireform load and fire them in your chamber, see if that does not fully form them.

 

[LHSmith]

When initial fireforming I coat the neck and shoulder with Imperial die wax and have the bullet just into the lands. I use 70 % book maximum load (x .7) of H4895 listed for the parent cartridge for Ackley Improved chambers.
Edit to read "maximum" load NOT "starting" load. Hodgdon claims it is safe to reduce charge weights of H4895 by taking maximum load listed and multiplying by .6 (60 % formula) IF H4895 is among the powder listed for that cartridge.
Just like fireforming for the PPC and 30 BR I don't expect the case to be fully formed until the 3rd firing

 

[SeabeeKen]

When initial fireforming I coat the neck and shoulder with Imperial die wax and have the bullet just into the lands. I use 70 % book starting loads (x .7) of H4895 for Ackley Improved chambers.

An AI chamber that needs to have the bullet jammed is not properly headspaced.
As posted earlier, he needs to up the powder charge and a heavier bullet would also help. A fast rifle powder is also helpful. As Ackley said, the load should be snappy

 

[6.5 forever]

In the past, I've fire formed 500 .243 winchester cases in my Savage 12FV 243 AI with every one forming to satisfaction. Recently I purchased 100 pieces of new Srarline brass and had three or four rounds that after three firings had very rounded, unformed shoulders. (See case on right) Wondering if anyone has had this issue. Thank

Compare the weight of the problem cases against the good ones. You might find the problem cases are heavier, maybe thicker. Thus not forming.

 

[rwj]

Anyone else concerned about those bright rings near the base and shoulder? I’d be checking the cases for excess wall thinning in those areas…

 

[Kracken McGraw]

Anyone else concerned about those bright rings near the base and shoulder? I’d be checking the cases for excess wall thinning in those areas…

Those at the base are just the end of the chamber, I suppose.

 

[SD guy]

You can try annealyng & a higher pressure load.

As I understand Fire Forming is best done with faster burning propellants.

No I have not had such issues.

What are you doing to achieve or substitute for head space controle?

 

[JFrank]

I wonder if the chamber is sealing on the case with the rounded shoulder ?

 

[Cloudrepair]

Have you cheched the chamber with a headspace gauge ? That is the first thing i would want to know for sure . Maybe they arent seeling because of brass to thick like what was said above ? I havent had a problem like that with any of my ai's have you measured the cases to unfired cases at 200 line and shoulder?

 

[Ackman]

When initial fireforming I coat the neck and shoulder with Imperial die wax and have the bullet just into the lands. I use 70 % book starting loads (x .7) of H4895 for Ackley Improved chambers.

That's very wrong, 70%.....No. With the same powder and bullet you plan to use, start with a max load in the reloading manual *FOR THE STANDARD CARTRIDGE and go up until you get to best accuracy. NOTE: It won't be a lot, somewhere between the maximum factory load and the load you'll be using in formed brass. Then with formed brass just go up from there slowly and find best accuracy and pressure. It's very easy and not really "fireforming", it's shooting very accurate, useable, field loads that are faster / just as accurate as the standard chambering and also produce a formed case.

 

[DLCrocket]

A lot here to look over and try. FYI, I'm using 42 grains of H414 and 70 grain Sierra Blitz Kings. I took a chamber measurement and seated bullets .002" off the lans. 47 out of 50 rounds formed well. Next I'll check the case weights. Unfortunately, I've not ventured into annealing yet. That will come.

 

[Straightshooter1]

A lot here to look over and try. FYI, I'm using 42 grains of H414 and 70 grain Sierra Blitz Kings. I took a chamber measurement and seated bullets .002" off the lans. 47 out of 50 rounds formed well. Next I'll check the case weights. Unfortunately, I've not ventured into annealing yet. That will come.

Annealing is your solution!

 

[Bill Norris]

Fire-forming AI brass needs good max parent case loads and jam to lands @ .020 ideally with a slower powder.

 

[DLCrocket]

Fire-forming AI brass needs good max parent case loads and jam to lands @ .020 ideally with a slower powder.

Hey Bill, you're saying .020 into the lands?

 

[Krogen]

That's very wrong, 70%.....No. With the same powder and bullet you plan to use, start with a max load in the reloading manual and go up until you get to best accuracy. NOTE: It won't be a lot, somewhere between the maximum factory load and the load you'll be using in formed brass. Then with formed brass just go up from there slowly and find best accuracy and pressure. It's very easy and not really "fireforming", it's shooting very accurate, useable, field loads that are faster / just as accurate as the standard chambering and also produce a formed case.

You must be joking, or I'm misreading your post. Start at the max and go up? Maybe you mean the max for the unformed case size, but still . . . . If this is how you do it, I don't want to be next to you on the line.

 

[Big_Daddy]

That's very wrong, 70%.....No. With the same powder and bullet you plan to use, start with a max load in the reloading manual and go up until you get to best accuracy. NOTE: It won't be a lot, somewhere between the maximum factory load and the load you'll be using in formed brass. Then with formed brass just go up from there slowly and find best accuracy and pressure. It's very easy and not really "fireforming", it's shooting very accurate, useable, field loads that are faster / just as accurate as the standard chambering and also produce a formed case.

You must be joking, or I'm misreading your post. Start at the max and go up? Maybe you mean the max for the unformed case size, but still . . . . If this is how you do it, I don't want to be next to you on the line.

I agree Krogen.....
Never heard of this technique before.....