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Thread: Is opening case mouth necessary

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    Member fishingyoda's Avatar
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    Default Is opening case mouth necessary

    I am just getting into reloading and found that loading some 45 colt rounds if I skip the second die that opens the case mouth it seams that I can seat the bullets just fine and when I used the second die the completed round won't drop into my cylinder. I'm using hornady xtp jacketed bullets. Also I was currious i haven't figured out the case trimmer all my cases are once fired from factory loads and they were all pretty uniform length but longer then the trim to length so I left them as they were and my oal is still under the max oal and they cycle through the gun is that normal to not trim them in this case?

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    Don't expand the case mouth too much, just enough to start the bullet. Cast bullets need a bit more case mouth flare than jacketed. You then need to crimp the finished round, which closes this case mouth tight on the bullet and allows it to chamber freely. This crimp (fourth function) is done by readjusting the seater die, (after seating) or a separate crimp die, be it taper crimp, roll crimp, Lee factory crimp, or Redding Pro crimp ( a taper and roll combined).

    I don't trim revolver cases, usually the length doesn't vary enough to matter. it will make an in-consistant crimp but I can usually live with that. You didn't mention rifle or revolver but rifles may have more strict requirements for seating depth, crimp, etc. Heavy loads in revolvers will need a strong crimp. Get used to the process and the feel of a good crimp.
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    Moderator Paul H's Avatar
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    If you're using jacketed bullets, you don't have to expand the case mouth. For cast bullets, a slight bell is needed to keep the case mouth from shaving lead. One alternative is to use a bridge reamer or vld reamer to create a shallow chamfer for your case mouth. So long as the sizing die doesn't size the case too small, the gradually chamfered case mouth will allow a cast bullet to be seated w/o shaving lead.

    That said, for straightwall cases I usually use the second die in the set and adjust it for the minimal amount of belling. For bottleneck rifle rounds I use the bridge reamer.

  4. #4

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    As memory serves, the sizing die will make the case slightly undersized and the second die, the expander die, opens it back up to proper inside diameter to hold the bullets properly, not just to bell the case mouth. If your sizing die doesn't make the bullets hard to install in the case, then either the bullets are undersized or the sizing die is oversized.

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    Member fishingyoda's Avatar
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    Its a revolver 454 super rh alaska. The 2nd die seemed to open the moouth way to much as the bullets would just fall all the way to the bottem of the case if i let them and I havent figured out how to crimp them yet. I did some research and after reading several people who said if your shooting under 1000fps you shouldnt have to crimp them on a 45colt load. So i loaded up some and took them out. I shot the first 5 in my 6gun and then remeasured the last round before fireing and it hadnt moved at all. I am going to go test some more today but I dont think this is going to be a problem. I am very new to reloading and this is why I decided to start with the 45colt and not just start loading up the 454 casull rounds. I started with 230g xtp in some once fired brass with 8gr unique i think my oal is .oo3 under what the book recomended for similar bullets. they seemed to shoot very well and much more acurate then I am normally capible of. I guess time will tell. Hopefully I can figure out how to crimp them with the 3rd die until i can buy one of the lee fcd's.

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    If you can drop the bullet all the way in after using the second die, either the die is wrong or you are using it wrong.

  7. #7

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    It also depends on bullet diameter in relation to the ID of the sized case, the size of the expander ball in die 2, chamfer of the case, heel of the bullet, case hardness after multiple firings and sizings, and case design. You can get away with things in a straight case that will haunt you in bottlenecks.

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    Quote Originally Posted by fishingyoda View Post
    Its a revolver 454 super rh alaska. The 2nd die seemed to open the moouth way to much as the bullets would just fall all the way to the bottem of the case if i let them and I havent figured out how to crimp them yet. I did some research and after reading several people who said if your shooting under 1000fps you shouldnt have to crimp them on a 45colt load. So i loaded up some and took them out. I shot the first 5 in my 6gun and then remeasured the last round before fireing and it hadnt moved at all. I am going to go test some more today but I dont think this is going to be a problem. I am very new to reloading and this is why I decided to start with the 45colt and not just start loading up the 454 casull rounds. I started with 230g xtp in some once fired brass with 8gr unique i think my oal is .oo3 under what the book recomended for similar bullets. they seemed to shoot very well and much more acurate then I am normally capible of. I guess time will tell. Hopefully I can figure out how to crimp them with the 3rd die until i can buy one of the lee fcd's.
    Yeah....something is wrong here. Disassemble the second die. (Brand name if dies would be helpful)The expander can be unscrewed from the body. This stem is made various ways, but for your 454/45 Colt is a two step expander. The first part should be about .002 to .003" smaller than bullet diameter. Bullet diameter is .451" to .452". Measure this dimension. You could have the wrong size expander plug in the die. The second step of the expander is for flaring or belling the case mouth. The die should be adjusted so the first step of the expander plug enters the case fully and the second larger diameter step should only bell or expand the case mouth as needed to start the bullets. Screw the #2 die body down to contact the shell holder then slowly screw down the expander to just start this slight belling of the case mouth. See how this works for you.
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    Member fishingyoda's Avatar
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    murphy, they are rcbs dies ill give that a try when it warms up a bit I dont have heat in my shop right now. I shot about 40rounds using my same method just skipping the 2nd die and not using a crimp and they all shot fine. Im using .451 diamater bullets Ill definately have to figure out this second die and the crimping before I try loading any casull rounds. thanks for all the advice everybody.

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