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Topic: Doughnuts in the necks (Read 408 times) previous topic - next topic

Re: Doughnuts in the necks

Reply #16
Good point Eric to test on fired brass. Think I might use a pin gauge though instead of a bullet. A pin gauge that just clears the mouth of the neck with fired brass.

Re: Doughnuts in the necks

Reply #17
It would be cheaper for me to just buy new brass. Lol, like 180 batches of it!!
I'm not saying it's a bad machine, just expensive.
Classic if you build it, someone will buy it.

I would go that route too if anyone made necks that were perfect out of the box.

Re: Doughnuts in the necks

Reply #18
 Its kinda funny that my 6.5x284 is the only stick i have that i have to deal with doughnuts in.. not sure why that is...

 
 I just ran into the same issue with my 6.5-284.  I loaded some rounds for the practice and all of them were hitting a hard spot when seating.  In the past I've used the neck reamer and I was going to do so on my next set of loads I do for this cartridge.   As part of my neck trimming, I also run a bronze brush down the necks....this helps to clean up some of the marks left by the reamer.

Good thread.....some good insights provided.
Bob
If everything seems under control......you're just not going fast enough

Re: Doughnuts in the necks

Reply #19
I think i will try what eric suggested and run my reamer in the fired cases.. then size them and run them through a expander mandrel.. pushing anything thats left to the outside then turning the necks.. thanks for all the input guys
Grant

Re: Doughnuts in the necks

Reply #20
I would go that route too if anyone made necks that were perfect out of the box.
Necks will never be perfect out of the box.
My belief is once turned and fired, using a bushing die the bushing will only size the upper 2/3 of the neck leaving clearance to any donuts.
Following Dave's advice on FL sizing after 5-6 hits and returning necks donuts would be a non issue  making those 180 sets of brass last a few lifetimes.

Re: Doughnuts in the necks

Reply #21
If a guy is using the right bullet reamer throat combination donuts are not an issue until it builds up enough that it starts to interfere with chanbering at the neck shoulder junction IMO
Dave

Re: Doughnuts in the necks

Reply #22
I know alot of people say the doughnut isnt a issue if your seating the bullets bearing surface above it.. im not sure i buy into that but it may be the case. To me that doughnut inside the neck is chocking the neck down regardless where the bullet is seated.. i will rid mine of the dreaded doughnut.. lol
Grant


Re: Doughnuts in the necks

Reply #24
Sorry if this is a dumb question but, if I shoulder bump first, then neck size with a Lee collet die, how can a doughnut form? I realize the collet only squeezes the neck but the mandrel itself goes into the case past the neck-shoulder junction; I'm thinking the doughnut would get expanded by the mandrel.

Chris

 

Re: Doughnuts in the necks

Reply #25
The problem is chris the shoulder is thicker than the necks and when that shoulder starts migrating into the necks you develope a doughnut.. the collet die may very well squeeze that thicker part on forward as i dont have any issues with any of the calibers i use the lcd on..
Grant

Re: Doughnuts in the necks

Reply #26
Grant, that is an excellent point that should have occurred to me....lol.  I've been wondering why the 6.5-284 has this problem more pronounced than the CM's or even the Grendel.  It really caught me by surprise last weekend when I was prepping for the Monday Practice.  You said it, I use a collet die on everything except the 6.5-284.......so Chris' observation is pretty much on track as well that the collet will definitely help to minimize the effect of the doughnut forming process.
Bob
If everything seems under control......you're just not going fast enough

Re: Doughnuts in the necks

Reply #27
Sorry if this is a dumb question but, if I shoulder bump first, then neck size with a Lee collet die, how can a doughnut form? I realize the collet only squeezes the neck but the mandrel itself goes into the case past the neck-shoulder junction; I'm thinking the doughnut would get expanded by the mandrel.

You are not going to move brass up or down the neck with sizing (FL, bushing, or mandrel). The sizing will however move brass laterally (in or out). Chris I agree the collet die mandrel should move the donut out, just like any mandrel should, but I don’t believe the collet puts enough pressure at the neck shoulder junction to move it up or down. The whole purpose of cutting into the shoulder during neck turning is to give the donut brass a place to move into when the case is fired in the chamber. If that void or cut space at the shoulder neck junction is not present, even though the collet mandrel pushed the donut out, it is going to come right back inside during the first firing because the chamber neck junction forces it back in. Gotta have a space for it to move to.

Re: Doughnuts in the necks

Reply #28
Throating reamer.....done. Seriously, if you are committed to a certain bullet why not get the freebore pushed out to keep the bearing surface ahead of the donut. I am in the camp that does not see problems with the presence of a donut if the bearing surface stays above it.

Re: Doughnuts in the necks

Reply #29
You are not going to move brass up or down the neck with sizing (FL, bushing, or mandrel). The sizing will however move brass laterally (in or out). Chris I agree the collet die mandrel should move the donut out, just like any mandrel should, but I don’t believe the collet puts enough pressure at the neck shoulder junction to move it up or down

Jerry i believe the way the collet die works it would put the most pressure on the doughnut area since that is where the cone part of the collet closes in the sleeve that forces it closed.. and since the mandrel keeps the brass from moving in and the collet keeps it from moving out the next path with the least resistance is forward.. could be wrong but thats the reason we dont see doughnuts when using a lcd i believe...
Grant