Forming 7 stw brass

[light rain]

I have a few hundred 300 h&h brass I am trying to make into 7stw brass. I just found out I had to use a full length residing die to bump the shoulder back. But I am leaving a small donut in the top of the neck. Is that normal it fists in the chamber, will it blow out ? Am I on the right path?

 

[Gary in MD]

I would fire form those with the bullets kissing the rifling and a good stiff charge of powder, not a "light" load. I formed my STW brass from 8mm Remington magnum brass. RL 22 and IMR 7828 gave outstanding accuracy with 140 and 150 grain Nosler ballistic tips. I always use the federal magnum primers.
Just my results for a long range hunting rifle, not a match rifle.
Gary

 

[dkhunt14]

Where in the neck are these donuts? At the mouth or back at shoulder? Matt

 

[light rain]

Where in the neck are these donuts? At the mouth or back at shoulder? Matt

They are right at the mouth

 

[rickiesrevenge]

Can you post a pic of the case? I don't quite understand what you mean by a donut at the mouth.

Aaron

 

[dkhunt14]

Are they too long that the end of the neck hits in the die? Matt

 

[light rain]

Are they too long that the end of the neck hits in the die? Matt

They are the same size as a normal stw case. I just read a post on longrange hunter and he doesn't have the donut in the neck.

 

[dkhunt14]

A picture would be nice. Matt

 

[light rain]

A picture would be nice. Matt

I dont know how to pist a photo from my phone or I would.

 

[Dusty Stevens]

I bet your case is too long and the die is crimping it- just a WAG

 

[dkhunt14]

I bet your case is too long and the die is crimping it- just a WAG

Dusty,That is what I thought also. That's why I asked where the bulge was. Then I asked about length. That is the only time I ever saw it happen. Matt

 

[Gary in MD]

I think you guys are right about the case being too long. It's either that or the mouth of the case is making contact with the opening of the sizing die and it is being "closed up" a bit as it's entering the die.

Gary

 

[light rain]

Guys thanks again for your help. I am greatruly yall chime in! I neck sized 5 of them to where they would fit in the chamber. I put 20 grains of blue dot in the case and maltomeal meal and fired them. This was my 2nd attempt at fireforming. It worked great. No donut or bulges anywhere. I think I will do 5 more then fire live rounds through those cases to see what the result is.

 

[rickiesrevenge]

Here's the pictures of the cases he sent me. It looks like the case mouth is flared just a bit.

 

[light rain]

Here's the pictures of the cases he sent me. It looks like the case mouth is flared just a bit.
View attachment 973352 View attachment 973353

Thanks for posting those. They fireformed well. Out of 50 6 split necks. I haven't shot a full load out of them yer but will tomorrow

 

[rickiesrevenge]

Where did they split? Seems like you always loose a couple but 10% is too much IMO. I'd anneal them before you try to fireform anymore. I've seen the flared case mouth before when forming brass. Even in my Butch Lambert forming die that doesn't have anything for the case to hit so I know its not from hitting the die. I kinda think its from going down in too big of increments.

Aaron

 

[light rain]

Where did they split? Seems like you always loose a couple but 10% is too much IMO. I'd anneal them before you try to fireform anymore. I've seen the flared case mouth before when forming brass. Even in my Butch Lambert forming die that doesn't have anything for the case to hit so I know its not from hitting the die. I kinda think its from going down in too big of increments.

Aaron

They split right on the shoulder, I anieled them on a bench source. We did question however if we needed to get them hotter for that much of a streching and maybe lower.

 

[AckleymanII]

I worked up a load with the 8 Rem mag brass and hunted with it because it shot very consistant 1/2" groups with 120 Nosler Solid Base lead tip bullets(R#22) and the 140g Nosler CT bullets(IMR 7828).

You may try using the 7mm bullet seater to help neck down first instead of the full length sizer, just set the headspace with a solid feel. Then after necking down, you will probably have to trim the length because the cases grow when you neck them down.

 

[DHD]

As mentioned already, that is a flare not a "donut". It happens to me every time I size down too much in one pass. The only time it was an issue was in a 308 (Hornady brass that has thin necks in a generous chamber), so I sized in 2 steps.

Don't know why it happens, but you probably have already moved past this issue.

 

[light rain]

As mentioned already, that is a flare not a "donut". It happens to me every time I size down too much in one pass. The only time it was an issue was in a 308 (Hornady brass that has thin necks in a generous chamber), so I sized in 2 steps.

Don't know why it happens, but you probably have already moved past this issue.

Thanks for the reply, yes I moved past it. I found even with that flair it chambers and fireforms, I am going to aniel a little further down this next batch to see if that helps to not have splits. Just when you think you have a grasp on reloading I go back to preschool.