Fixing Dented Case Mouths

[txguero]

Just recently started loading/shooting 6BR (Lapua brass). The rifle I’m shooting them out of dents case mouths upon ejection, and if I gingerly work the action I sometimes have FTEs. So I’m gonna have to work with the dents.

This brings me to my reloading process. Currently using Redding Type S full length bushing die for sizing, but from what I have read it is better to remove the expander ball from these dies. Do you think the external bushing sizing of the neck will straighten out the dents? Should I use the expander ball that comes with the die? Or should I add another step to my process and purchase a Sinclair mandrel to finish everything off?

 

[cdeiglmeier]

What action are you running? I've only been reloading for a little over 2 years so I'm by no means an expert but I would Take the expander ball out of your full length die (what I do) and run all your cases through a sinclair mandrel to set neck tension and straighten mouths if dented (which is what I do as well). Better consistency this way than the expander ball in the full length dies.

 

[txguero]

It's a remington 700. I was hoping I could get by without having to buy the sinclair die but I guess it does give you the bonus of less neck runout.

 

[aprocast]

Buy a lee collet die

 

[rgv]

In addition to the above posts, order a spare ejector spring and shorten it.

It will be easier on the cases on ejection.

 

[lightman]

I pick up a lot of range brass with dented or bent case mouths. I keep a polished center punch on my bench for straightening these out. A 50 caliber bullet does the same job on larger caliber pistol brass.

 

[NW Valkyrie]

I'm surprised your 700 action is denting case mouths. I would definitely fix the ejector issue, as that is not expected behavior from a bolt gun.

To answer your question about if the sizing die will straighten out dented cased mouths if you remove the expander ball:

My experience is yes, it will most definitely straighten it out. I ran a 6.5 Grendel Auto this past summer, and every case mouth was bent. One pass through a sizing die with no expander and they all come out round. (which are then run through a mandrel)

My suggestion is resolve whatever is denting your case mouth and pick up a mandrel.

 

[txguero]

I'm surprised your 700 action is denting case mouths. I would definitely fix the ejector issue, as that is not expected behavior from a bolt gun.

To answer your question about if the sizing die will straighten out dented cased mouths if you remove the expander ball:

My experience is yes, it will most definitely straighten it out. I ran a 6.5 Grendel Auto this past summer, and every case mouth was bent. One pass through a sizing die with no expander and they all come out round. (which are then run through a mandrel)

My suggestion is resolve whatever is denting your case mouth and pick up a mandrel.

I think it has to do with the short/fat case of the 6BR. Pretty early in ejection/extraction, the body is no longer supporting the tension from the ejector and the force is rapidly applied to the long neck of the cartridge as the body clears the chamber. Could be wrong but that is my theory so far. I think I will try the full length die with no expander (since I have to do this step anyway) and see how they look/measure. Then I may or may not be looking into getting a mandrel. It's on my wish list anyway for certain applications but I am really hoping to not add a step if it's not absolutely necessary.

 

[Bradu]

I run the expander ball in most of my type s dies. The only reason I won't run it is in the 2 cartridges that I neck turn for.

 

[aprocast]

As has been said, fix the issue
Shorten the ejector spring

 

[want2learn]

may i ask, which expander is most appropriate to purchase....can you use a neck turning set up or is it best to pick up the sinclair expander? thanks

 

[Foul Mike]

I seldom have a dented case mouth but when I do, I do as Lightman does and use a polished tapered punch to iron them out a bit.
I agree with others here that you need to figure out what is causing it.

 

[want2learn]

thanks...i agree, hence the post. I'm working on it. Will pay particular attention to lubing. I really thought i was judicious but will do better.

 

[txguero]

I use the cheap $10 Sinclair mandrels and $30 dies.

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most people seem to go with the expander mandrel which is .001 under bullet diameter

 

[6brshooter]

I run the expander ball in most of my type s dies. The only reason I won't run it is in the 2 cartridges that I neck turn for.

Dead on the money. If you are not turning nks, than you should use the expander ball. Unturned nks arent consistent enough to just rely on bushing. Realistically, a bushing die is just for minimal resizing of nk. If nks are turned, no expander ball needed. If nks arent turned, no expander ball will result in inconsistent nk tension, solely determined by inconsistent nk thickness. I've had new lapua brass vary as much as .003 in nk thickness, in 200 pieces of brass.

 

[Foul Mike]

I think that the OP is new to this and may be like me as I don't understand nks and nk and why do you not put in an e to make it nEck sizing? Is it too hard to explain what you are talking about? or just saving a key stroke?
I gave it my best shot and that may not be good enough.
I am old and stupid but I know how to spell as to how to help others. FM

 

[wil_pt]

may i ask, which expander is most appropriate to purchase....can you use a neck turning set up or is it best to pick up the sinclair expander? thanks

K&M expand mandrel plus the press adapter for around $25 at midway.

 

[scatterbrains]

You can remove the expander ball and get a tapered expander that will greatly help smoothing the necks out. You can also pickup a Lyman Mdie and use the NOE expander plugs.