I just bought tools for neck turning. It might not even help my factory rifle but I mainly want to start learning for the future when it will help. What depth should I set my cutter so that it will just clean up the necks and not remove too much material? I am using lapua .308 brass. Thanks
Neck clean-up, cutting depth?
- Thread starter arthurj
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I just went thru the same deal. What I did was adjust the cutter down till it just barely touches the (sized) case..Also trim it to whatever length you want as well before hand. Give it a turn. You want 70-80% of the case neck touched and removed by the cutter. If not that much after the first pass..Lower the cutter a bit more. You barely have to move that cutter to have it cut as well. Just a tiny bit of adjustment at a time.
This method worked best for me and I did not ruin a single case.
I hope you got the power adaptor as well from sinclair! Makes life sooooo much easier. It works with the little cordless scredriver. Works great oo, you get a better cut as well.
Almost forgot, get as close to that shoulder as you can...to the point of just touching it. If you dont, you will develop a Dougnut on the inside of the neck at that point after you fire it a few times
Joe
This method worked best for me and I did not ruin a single case.
I hope you got the power adaptor as well from sinclair! Makes life sooooo much easier. It works with the little cordless scredriver. Works great oo, you get a better cut as well.
Almost forgot, get as close to that shoulder as you can...to the point of just touching it. If you dont, you will develop a Dougnut on the inside of the neck at that point after you fire it a few times
Joe
I wish I had ordered that adapter! I will have to have one I'm sure. I figured I would probably need to just use the "guess and check" system. I've got the adjustment fixture but it only reads thousandths. I bought a neck micrometer also, should I take a reading on a high spot and set the depth for .0005 off of that or what?
ArthurJTo get concentric necks which is what you are after they must be cleaned up 100%.If you only clean them up 80% of the way that means 20% of the brass is a different thickness so why bother at all? There is no sense in doing a half *** job and later trying to correct for bad habits learned on a loose chamber.Start by necking down a piece of brass then expanding it back up with the mandrel.This will ensure all your necks have the same pre-load on them.You need to liberally coat the mandrel and inside of your necks with Imperial Sizing Die Wax or Automatic transmission fluid mixed with STP (2 to 1)oil treatment.Do a quick cut on a piece of brass that will be sacrifised that cleans up the neck 90%.From there adjust the tool in very small increments until that piece of brass is 100% cleaned up.This piece of brass should be done by hand and you should keep applying lubricant so it spins freely and to avoid heat build up.Wait atleast a half hour and re-run it on the turner without changing anything.If you feel tight spots are places were it feels like it is dragging on one spot keep turning it until this becomes silky smooth.These are little ridges or high spots.Did i mention that lubrication is very important.This dragging will be felt on your initial cut even with proper lubricant but it shouldn't be felt after your final cut.You also need an old toothbrush to keep the chips from trying to go through the cutter and galling your brass.Keep the chips brushed away at all times.The outside of that one case should look shiny smooth.Measure that case now and see what it measures.Now seat a 30 caliber boattail bullet(no pressure ring) and pull that bullet back out and measure it again.Alot of people skip that step and there brass comes up too loose in the chamber.On typical 30 caliber brass using a bullet that measures 0.3080 you would add twice your neck thickness plus the bullets diameter to get something like this. 0.308 + 0.013 + 0.013 = 0.334 which would work well if you had a 0.335 or 0.336 tight neck chamber which is very common.If you had a 0.332 tight neck chamber your brass would need to be turned thinner.On a factory chamber i would clean it up 100% measure it and record the thickness.You can now do your initial turning under power and your final cut by hand.When done i usually use 0000 steel wool on the outside for a mirror smooth finish.If your under power you can put some steel wool on a worn out cleaning brush and run it inside the necks with a little Flitz metal polish on it to get the inside very smooth as well.Remember the lubricant and touch the mandrel that the neck rides on against your lip.If it is hot to the touch your going to fast.Slow down or let it cool.This is important on the final cut.Lynn
royinidaho
Well-Known Member
Lynn,
Appreciate the detail of your post learned a lot. Like arthurj I'm shooting a factory chamber. First I wonder if uniform necks are that big of a big deal, though I'm trying to hold 1/2" groups at 200 yds in preparation to working up a drop chart out to 800 yds or so with a 338 Win.
I've been successful in finding "the load" that gets me the consistency that I'm after "most of the time".
The following question indicates my hesitancy in setting up to turn the necks.
My question: if "every" case is to be turned 100% then it would be the thinist case neck that sets the thickness of all the cases.
Is this a potential problem? i.e., too thin necks?
Not having the slightest idea of how to determine chamber neck dimensions and not wanting to ruin the 100 sorted (by weight) cases I have I'm kinda askeer'd. (if ya know what I mean) BTW, have the tools just afraid to start turning.
Appreciate the detail of your post learned a lot. Like arthurj I'm shooting a factory chamber. First I wonder if uniform necks are that big of a big deal, though I'm trying to hold 1/2" groups at 200 yds in preparation to working up a drop chart out to 800 yds or so with a 338 Win.
I've been successful in finding "the load" that gets me the consistency that I'm after "most of the time".
The following question indicates my hesitancy in setting up to turn the necks.
My question: if "every" case is to be turned 100% then it would be the thinist case neck that sets the thickness of all the cases.
Is this a potential problem? i.e., too thin necks?
Not having the slightest idea of how to determine chamber neck dimensions and not wanting to ruin the 100 sorted (by weight) cases I have I'm kinda askeer'd. (if ya know what I mean) BTW, have the tools just afraid to start turning.
That is what I was wondering also. "Ideally" I would give each neck a 100% turn to achieve uniform thickness, but I was wondering if that would increase the clearance in the neck of the chamber too much. Being as this is a factory rifle I have no clue what size the neck of my chamber is. Can I measure the necks of fired cases to get a "guestimate?" I know lapua brass is thicker than most so could I go ahead and trim each neck to .0130?
Me I would do the 80% cut see how they shoot and seal can always cut some more off and see if an improvement. I turn alot of neck for my tight neck rifles etc and one thing is cann't add anything back. You can cut too much neck off on a factory chamber. Say the thinest part of the neck miked at .014 I'd turn neck to .0145 or even .015. The thickest part of the neck extends all the way down the body of the case and brass will flow up inside the neck which forms the donut so you need to ream the inside of the neck after afew firings. Sinclair sell different size inside neck reamer for a reason. When you get into bushing type dies for the factory chamber that 20% uncut neck really isn't a big thing. You want to see an even gas seal around the neck and that is kind of a given in a tight neck rifle. Well good luck.
