Case Forming Questions

[marukka]

I know this isn't the most appropriate forum to post this on, but i'm sure plenty of you have a lot of experience with case forming. Do you guys know of a forum better suited for wildcats and obscure cartridges?

I'm trying to form 40 Super brass from Lapua 308 Win with a Redding FL sizing die. When I pass it thru the sizing die, the neck OD is sized to 0.393 when it should be 0.424. If I cut the shoulder/neck off the case before sizing, the mouth comes out belled. I don't have a proper annealing setup, but tried over annealing a case on my stove, and it didn't seem to help, other than making it far easier to pass thru the die. Is there anything I can do, so that the necks are formed to the correct diameter, and to prevent the belled mouths?

What is the best way to remove excess thickness from the necks? I've tried using a 35 cal reamer, and then turning the necks to achieve the correct thickness. I then pass them thru the expander die far enough so the ID of the neck/shoulder junction is sized to ~.390, this has the down side of over expanding the neck to a OD of ~.430. If I pass it thru the sizing die again, to correct the neck OD, it has the result of reducing the ID of the neck shoulder junction back to ~.370. I'm guessing you guys are going to tell me to have a reamer/turning mandrel custom made.

Thanks.

 

[artbosco]

I'm trying to form 40 Super brass from Lapua 308 Win with a Redding FL sizing die. When I pass it thru the sizing die, the neck OD is sized to 0.393 when it should be 0.424. If I cut the shoulder/neck off the case before sizing, the mouth comes out belled. I don't have a proper annealing setup, but tried over annealing a case on my stove, and it didn't seem to help, other than making it far easier to pass thru the die. Is there anything I can do, so that the necks are formed to the correct diameter, and to prevent the belled mouths?

You might try the 1911 Forum since this is a handgun cartridge, and post in the Reloading section. Additionally you might also want to get one of these for sizing to proper dimensions: http://www.midwayusa.com/viewproduct/?productnumber=528385 Try Googling "Forming 40 Super Brass" for additional info. Also call Starline Brass and ask one of their Techs for suggestions/help with your project: http://www.starlinebrass.com/

 

[bozo699]

marukka,
Welcome to the forum, best gun forum going for sure. Try giving 357Mag a p.m he is a forum member here on 6br and has done quite a bit of wildcatting and case forming, he is a real nice guy and I am sure he will help if he knows the answer to you problem, best of luck.
Wayne.

 

[spclark]

Not familiar wit this cartridge but it looks like Midway has nickel-plated 40 Super on hand for $27.49 / 100:

http://www.midwayusa.com/viewProduct/default.aspx?productNumber=768997

Starline makes it too but they're backordered at present, awaiting sufficient demand to do another run.

Perhaps the Lapua 308 brass is just too thick to work well? An article on Wikipedia describes starting with .45 Win Mag:

http://en.wikipedia.org/wiki/.40_Super

 

[artbosco]

After reviewing my Gun Digest "Big Fat Book of the .45 ACP" where author Patrick Sweeney calls the 40 Super an OFFSHOOT of the .45 ACP and speed king of the middlebore cartridges, and then goes into detail on the operating pressures generated, his final suggestion on reloading it, is to acquire the proper brass and not go and do something silly.

For what it's worth, that sounds like a good idea.

 

[marukka]

I am somewhat hesitant to buy that RCBS die. I talked with RCBS over email a month or two ago, asking if I would need those dies. They didnt know and had to forward my email to their parent company ATK who said no, just a FL sizer was required. I then asked them what those form/trim/etc dies were used for, and neither RCBS nor ATK knew, they told me to ask MidwayUSA what they are supposed to be used for! It doesnt help that the trim/neck reamer/etc dies dont look like they would work on a Co-Ax press. I'm also trying to avoid having to spend $600 on a set of dies plus whatever it would cost for a traditional single stage press.

I'm also hesitant to buy the Starline brass, for one they ran out of stock, although a couple hundred cases are on gunbroker. When I emailed them asking what pressure it was rated to, they replied that they dont rate their brass for a particular pressure, just that it will meet or exceed factory brass. This doesnt inspire confidence since Triton never standardized the cartridge, I have 3 cartridge drawings which all differ, 2 of them were from the founder/CEO of Triton, and the other is from QuickLOAD/Tromix. DoubleTap makes their own 40 Super brass and its in stock, but they have the wrong type of primer pockets. To further complicate matters, the company which produced my barrel chambered it incorrectly, the neck is more than 0.01" too short, its closer to 400 Corbon than 40 Super. It seems that everyone just comes up with their own specs for 40 Super.

Regarding that gun digest book, it cant be based off .45 ACP, that would be 400 Corbon. 40 Super brass is longer than 45 ACP and it runs at at least twice the pressure. I talked Tony Rumore (owner of Tromix) who used to work for Triton, the brass they originally used for their load data was modified 45 Colt, then 45 Win Mag, and then finally custom made brass from Starline.

Is there any chance you could scan/take a picture of that article in the book for me? I've heard Triton loaded their brass to 37k PSI, DoubleTap does 32k PSI. Although according to the CEO of Triton, it is supposed to be able to send a 135gr bullet at 2000 FPS. According to QuickLOAD that would require a load in the 50k-60k PSI neighborhood. If i put some of the load data I have from Tony Rumore in to QuickLOAD, it says it would be at 80k-90k PSI!!! Because of the pressures involved and that Starline doesnt know what their brass is rated to, and DoubleTap rated their brass to 40k PSI, I'm trying to form brass from 308.

To be honest this entire venture is rather silly/foolish for me. I started reloading 40 Super with the only prior experience of 2 sets of 45 ACP reloads. I'm not going to try the full power reloads without a ransom rest/remote trigger.

Thanks for the feedback everyone.

 

[artbosco]

Regarding that gun digest book, it cant be based off .45 ACP, that would be 400 Corbon. 40 Super brass is longer than 45 ACP and it runs at at least twice the pressure. I talked Tony Rumore (owner of Tromix) who used to work for Triton, the brass they originally used for their load data was modified 45 Colt, then 45 Win Mag, and then finally custom made brass from Starline.

Is there any chance you could scan/take a picture of that article in the book for me? I've heard Triton loaded their brass to 37k PSI, DoubleTap does 32k PSI. Although according to the CEO of Triton, it is supposed to be able to send a 135gr bullet at 2000 FPS. According to QuickLOAD that would require a load in the 50k-60k PSI neighborhood. If i put some of the load data I have from Tony Rumore in to QuickLOAD, it says it would be at 80k-90k PSI!!! Because of the pressures involved and that Starline doesnt know what their brass is rated to, and DoubleTap rated their brass to 40k PSI, I'm trying to form brass from 308.

Sorry, I have no way of scanning/taking a picture of the article.

The best I can do is pass this along as an inexpensive source: http://www.amazon.com/gp/offer-listing/1440202192/ref=dp_olp_new?ie=UTF8&condition=new

Compared to $600 for dies and a press and $395 to $555 for a Ransom Rest http://www.ransomrest.com/RansomRest.html the book is just pocket change [$12.00 + $3.99 S&H]

 

[marukka]

Thanks, i used ransom rest as more of a generic term, i thought I saw similar but cheaper models from someone else. cant remember off the top of my head who tho.