Shooters Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
184 Posts
Discussion Starter #1
Gentlemen,

I have a question about caseforming. I have a 7x57mm Mauser, and thought I'd try to form some cases from 30/06 brass as I have tons of it around. I plan to use this formed brass for cast bullets only, to save my factory brass and to keep brass segregated. I annealed the 30/06 cases, partially necked them to 7mm, and trimmed them to just over final length. Then I lubed them and ran them into a 7X57mm F/L sizing die (turning them 1/3 turn and then going further), then trimmed them to final length. They formed ok, but as I tried to chamber them, there was a bit of resistance. I compared my formed case to a factory case and found that the shoulder was formed slightly forward. If I fire these with a starting cast load, will it be safe? Will the case then form to the chamber? I'd appreciate any help as I'd like to shoot these case tomorrow.

SSB
 

·
Super Moderator
Joined
·
9,463 Posts
From a distance, it's hard to say what 'a bit of resistance' is. IS it an effort to close the bolt? Is it about the same as when you rechamber an empty that has been fired in that chamber?

If the bolt is closing without major effort, then there are only two things that can go wrong. (1) barely possible that the bolt could be bound by strong tension and not let the striker fall...better test that. (2) Increased wear on the locking lugs...use good lube.

Once you fire them, they should fire form to the chamber.
----------
Did you use a the same shell holder? They do have variations in height, and one shell holder will push a case in farther than another even though they both fit the case correctly.
----------
Would do some measuring. Those 30-06 cases are going to have thick necks...not only from necking down, but because the 7X57 is a bit shorter and you are getting into the thicker part of the 30-06 case.

If you didn't neck turn/ream the necks, your resistance to closing may be beacue the case neck with a seated bullet is too large....even if it doesn't casue resistance, if there isn't enough slack to let the case neck make a clean release on the bullet (even a cast one) may run into some pressure problems.
 

·
Registered
Joined
·
184 Posts
Discussion Starter #3
Rib,

Thanks for the reply. Resistence is enough that I have to smack the bolt handle pretty good, but it IS from the case shoulder, not the bullet or neck. Yes I did use the same shellholder. Outside neck diameter is OK too. I think I'll be fine with a mild cast load to fireform. ANy experience with this situation?

SSB
 

·
Registered
Joined
·
3,124 Posts
If you have your full length die and it is set to just partially size your cases, like most of us do, then you need to use the full length sizing technique. What works fine with cases fired out of your rifle may need a little extra persuation with the formed cases. Brass does have a bit of spring to it and would not normally be noticed when resizing your cases that where factory or fired in your rifle chamber.

As far as the necks go, the outside diameter is meaningless unless there is a bullet seated in the case. You didn't say if that was measured with a loaded round or the formed brass. The dies will take it to outside diameter no matter what, it's when the bullet expands the case neck when it's seated that you need to check.
 

·
Registered
Joined
·
184 Posts
Discussion Starter #5
Kc,

I measured the neck with a bullet seated. Seemed fine to me. I was looking at the shoulder and it seems a bit rounded instead of sharp like a fireformed case. I think the shoulder may just be formed at an incorrect angle, and may "iron" out on firing. I'm thinking of fireforming without a bullet.

SSB
 

·
The Hog Whisperer (Administrator)
Joined
·
36,229 Posts
Run a case up into the sizing die, then look and see if there is any gap between the shellholder and the die before you bring the handle back down. There is normally some slack in the press linkage.

If the shellholder is contacting the die, you may just have a minumum chamber, or your dies could be slightly long.

So.... if that's the case, I'd suggest getting an extra shellholder and carefully taking a bit off the top. Should be able to put some sandpaper on something flat, and turn the shellholder over and rub it back and forth to grind a few thousandths off. They are pretty hard, though.

I'd try a few mild loads to see if the problem is solved during case forming. Odds are, it will be.
 

·
Super Moderator
Joined
·
9,463 Posts
Was froming .243's from .308's and ran into the same problem. There is enough spring back to make the ases a bit loner...my solution was to stone the shell holder a bit, so that it would push the case in a tad more, which solved my problem (using a single shot action, so there wasn't a bolt handle to "whap" on). Actually...once I stone it a bit, gave up and pushed it against an orbital sander to reduce it .005".

Could do the same with the sizer die...I just try to work on the cheaper part when I have a choice.

Shell holder still worked fine with standard cases so long as you don't set it hard against the die.
----------
If you really don't want to stone the holder, there is a "cheat" but it's time consuming. Start with cases sized in teh die as is..they will be the ones you have that are just a tad too long. Remove the decapping stem from the sizing die. Find a rod that is a good fit through the die to drive the case out. Screw the die out of the press a good bit. Lay a quarter across the shell holder. Set a case on the quarter and run it into the die (being screwed out, it won't size a thing yet...will have to adjust the die down). Keep lowering the die, knocking out the case, chambering it in the rifle until there is just a touch of resistance....it helps to marks-a-lot the shoulder area to be sure that is what is contacting. Lock the die down and size/drive out each case.
---------
Your problem may be that there will be one or two in your batch that are just a fraction longer than the rest...and you'll get that bolt handle suck 4/5th the way down but unable to get it all the way down or back up without a length of 2X4for persuasion.
 
1 - 7 of 7 Posts
Top