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Discussion Starter · #1 ·
After browsing the site, I'm almost convinced that I will need to turn necks at some stage in my case forming process from .444 Marlin to .260x444 Imp 40°. I'm still deciding on which turner to buy - K&M vs. Forster, but I have seen some gadgets which might solve the thick neck problem I'm running into. In my case forming process, I set the shoulder with a .375 JDJ FL, then neck down with a .308 neck size, then neck down again to .260x444 (I'm using a modified 6.5-06 Ackley Imp 40° die that has been cut down). The problem I'm running into is that the neck becomes so thick during the .308 step that the expander hangs on the upstroke of my press (Dillon 550) so much so that I've ripped the lip off of my shellplate (this happened on the first batch before I annealed the cases, as for the annealed cases, I've actually ripped the neck on the upstroke. As a result, I have to remove the expander to get a smooth return stroke, but I run into the same problem again with the 6.5 die. The hang-up isn't as stiff at this point, but it leaves the neck wavy and thickened on the end. I trim about .020 off the cases to make them workable and have actually gotten decent accuracy with this approach, but end up with a .218 neck length instead of the .220+ of the chamber. I see that Forster offers a "reamer" pilot that will work with my Redding trimmer, would the .308 reaming pilot be an option after necking down without the expander? At what stage do you guys think I should turn the neck? and should I turn twice between stages? My .260x444 chamber is standard to very slighty undersized in the neck so what thickness should the neck wall be? My loaded rounds are between .293 and .294Ø at the neck, which leaves the neck thickness at .015 right? Is this too much?
 

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There are a lot of issues here...

I'll see if I understand what you are up against here and try to offer some help.

After browsing the site, I'm almost convinced that I will need to turn necks at some stage in my case forming process from .444 Marlin to .260x444 Imp 40°. I'm still deciding on which turner to buy - K&M vs. Forster, but I have seen some gadgets which might solve the thick neck problem I'm running into. In my case forming process, I set the shoulder with a .375 JDJ FL, then neck down with a .308 neck size, then neck down again to .260x444 (I'm using a modified 6.5-06 Ackley Imp 40° die that has been cut down). The problem I'm running into is that the neck becomes so thick during the .308 step that the expander hangs on the upstroke of my press (Dillon 550) so much so that I've ripped the lip off of my shellplate (this happened on the first batch before I annealed the cases, as for the annealed cases, I've actually ripped the neck on the upstroke. As a result, I have to remove the expander to get a smooth return stroke, but I run into the same problem again with the 6.5 die. The hang-up isn't as stiff at this point, but it leaves the neck wavy and thickened on the end. I trim about .020 off the cases to make them workable and have actually gotten decent accuracy with this approach, but end up with a .218 neck length instead of the .220+ of the chamber. I guess it should be obvious that this is talking about length vs. diameter. If you are having to trim .020 to keep from binding the cases at the neck with those dies, then you have one of two options. Either you live with the cases being a little short and as they elongate during the course of the next firing/resizing process, you will gain some length and be able to trim to the desired length. Or, you may have to buy a set of dies that allows you to accommodate the longer neck. That is something you may wish to try. I see that Forster offers a "reamer" pilot that will work with my Redding trimmer, would the .308 reaming pilot be an option after necking down without the expander? This may be worth a try. However, this process is on a case that is still due for some sizing and thus may not be necessary. You might be better off attempting to achieve this in the next process. At what stage do you guys think I should turn the neck? You can try the process of turning them slightly at the outset, but my fear would be that you might have a tendency to be turning the material that will ultimately be part of the shoulder. So, I think I would recommend turning after the first sizing process. I think it best to turn the outside of the cases at this point to keep the overall geometry of the case concentric with the bore.and should I turn twice between stages? You will likely have to experiment with this. Turning twice seems unnecessary to me if I understand it all correctly. If you can, try to get the setup dialed to what will work. My .260x444 chamber is standard to very slighty undersized in the neck so what thickness should the neck wall be? You should be able to calculate this. You know the bullet diameter and the neck dimension. If you are looking for a tight fit neck, then I think I would work this down in increments of thousandths of an inch. My loaded rounds are between .293 and .294Ø at the neck, which leaves the neck thickness at .015 right? Is this too much? I think I would allow the function of the rifle dictate this. If you have enough neck tension so that you can cycle the rounds and the bullets don't dislodge in the magazine (I'm assuming this is not a single shot) then that should be enough. If you need a little more neck tension, either for accuracy or cycling the rounds, then you can either try a slightly thicker neck, again talking about increments of thousandths of an inch, or use dies that allow different sizing bushings to gradually decrease the size of the neck until you're rifle is functioning adequately and cycling, the necks aren't splitting and the accuracy you desire is achieved.
I don't know that reaming the insides of the cases is advantageous, unless you are taking advantage of benchrest dies, or there are wrinkles in the inside of the necks that can't be tolerated.

As you know, you are well into the region of "wildcatting". What makes this fun as well as frustrating is the process of experimentation and virtually conquering the obstacles. But my philosophy on trimming and reaming cases is that the brass material can always be removed, but cannot be added back. So, I try to minimize the amount of material removed, i.e only remove as much material as necessary to achieve the goals.

I guess my advice in a nutshell is to go slow. Try 5 cases, document the steps and results and see how it goes. Try 5 more cases if necessary and see how that process works and so on. This will take some time but hopefully won't cause you to go through too many steps, buy too much equipment and prevent ruining too many cases.

Hope this helps a little, but if you are still having trouble, let us know.
 

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HW, maybe I'm missing something, but having some some similar cases for another project, I have a couple of suggestions.
(1) Do all the necking down with the expander removed from the die.
(2) get a bar of cerrosafe and cast your chamber so you'll know exactly what size you'll need to finish up with.
(3) get the K&M neck turning tool with a .264 expandiron.

Cast the chamber. Do all the neck reductions. Anneal. Expand the neck. Turn if necessary. Fireform.

This is the process I used to form 7Alpo brass from 444 Marlin. The 7 Alpo is a rimmed, shortened 280Rem AI, not very different from your case. I did not need to turn the necks at all.

Rick
 

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necks

your doing alot of necking. Id consider annealing and neck turning and also not using the expander ball. You may even want to neck turn at the 308 stage instead of at the end. Id go with the K&M
 

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Discussion Starter · #5 ·
Thanks for the suggestions.

Steven: I should have mentioned that the rifle is an Encore. Thanks for the suggestions, I admit that I'll have to experiment with this process.

GreyFox: 6.5 Alpo is what's scribed on my barrel, didn't know many knew about the Alpo's. David White / precisionrifleworks.net did the re-chamber from a factory T/C .260 barrel. I hate to fool around with cerrosafe, seems to be quite an involved process. I may just ask David for the reamer dimension - would this be adequate.

All who responded have suggested removing the expander, so I'll go this route and looks like the K&M is the turner of choice.


Robbor - I did anneal the second batch of brass I formed at .444 and they worked better. After the .308 stage (with expander removed) , the neck looks thickest at the end and actually looks a little flared - I've trimmed this part off, but this costs me about 0.020" of neck length.


Again - thanks ALL who suggested. This a good board - one of my favorites
 

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Dittos to what Greyfox said. (I find myself in agreement with him often...And don't think that doesn't worry me!:eek: )

P.
 
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