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Setting up for neck turning...Problem with pilot fitting inside the neck 7mm Mag

Timbco84

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Full Member
Minuteman
Apr 20, 2013
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Oregon
Setting up for neck turning...Problem with pilot fitting inside the neck 7mm Mag

Here is what I am using...ALL BRAND NEW

-RCBS Rock Chucker Press
-RCBS Full Length Dies
-Forster Original Case Trimmer
-Forster trimmer mounted Neck Turner and appropriate .284 neck turning pilot


Here is the problem. I FL sized my once fired brass per Forsters instructions prior to turning the necks. I'm using once fired remington brass from my dad's Sako 7mm mag. I pushed the shoulders back .010" to have the headspacing negative .002" for my howa 7mm mag (his headspacing was .008" longer than mine). I went to put the first shell in the trimmer for neck turning and the pilot won't engage the neck. The pilot WILL engage the neck on the once fired brass prior to sizing, but forster says to size then turn. I have double checked everything to make sure it is 7mm mag/.284 specific. I can ream the inside of the necks to get the pilot to fit, but that is taking a fair amount of brass off the entire length of the neck. Here are my questions...

1. Should I be conserned that my FL dies are not opening the neck up enough, wouldn't this create a ton of neck tension if so?

2. Should I have turned the necks BEFORE FL sizing and assume the neck tension from the dies is "ok"?

3. Obviously I shouldn't be reaming all this brass post FL sizing just to get the neck turning pilot to fit right?

4. Should I be looking at a differnt brand of dies (forster)? Would this be a better option than my current set up?

Thanks for helping this newbee out, Spent the last 4 months aquiring reloading gear and reading as much as I can about it, only to run into some major hickups out of the gate.
 
The Sinclair Neck Turner I have also has a neck expander that is a .002 larger making it easy to fit on the turn pilot, not sure what Forster has. I prefer to turn necks before sizing and taking off only the high spots(50-75% of the circumference).
 
You are sorta misappling the technology. Neck turning is used to uniform the neck thickness so that every case sized with a die that uses neck bushings will have the same internal diameter and bullet neck tension. So what is happeningis the stock FL die closes down the necks too small to fit on the turning pilot. If you use a bushing die with the correct bushing the pilot will fit. The bushing diameter should be selected based on the neck thickness.
 
Sinclair expander die
Sinclair "neck turning" mandrel for the die

That is all.
 
You are sorta misappling the technology. Neck turning is used to uniform the neck thickness so that every case sized with a die that uses neck bushings will have the same internal diameter and bullet neck tension. So what is happeningis the stock FL die closes down the necks too small to fit on the turning pilot. If you use a bushing die with the correct bushing the pilot will fit. The bushing diameter should be selected based on the neck thickness.

I can appreciate your input. I am looking to turn the high spots off of the neck, creating the same neck thickness for the circumference of the neck. Thus, creating equal neck tension for the bullet. I understand where your coming from, but I think the technology applies weather full length sizing or bushing sizing IMO. Forsters instructions literally say "Outside neck turner- Used after case sizing" It doesn't say use after bushing neck sizing.
 
The Sinclair Neck Turner I have also has a neck expander that is a .002 larger making it easy to fit on the turn pilot, not sure what Forster has. I prefer to turn necks before sizing and taking off only the high spots(50-75% of the circumference).

I think that is what I am going to have to do. The .284" trimmer pilot fits fine after the FL resize, just not the turner pilot. I'll turn them prior to FL sizing next time around. I just really want to make sure my FL dies were opening the neck up enough for the bullet to be seated without a ton of neck tension.
 
Does your turning pilot cut? If not just spinning it will warm the brass and let it slide on. Either way you need to reopen the case mouth to .284 diameter. You need an expander die. And don't trim without sizing, that would be ??? Not smart.
 
I agree, my comment was only about FL sizing. You need to use a FL die with a neck bushing so you can control the neck size. I found the stock FL dies always size the neck too small for a turning pilot on all but the thinnest brass.
 
Does your turning pilot cut? If not just spinning it will warm the brass and let it slide on. Either way you need to reopen the case mouth to .284 diameter. You need an expander die. And don't trim without sizing, that would be ??? Not smart.

My Forster turning pilot does not cut. I have a RCBS Pilot Reamer, but for brand new it doesn't work that good, and I didn't want to take a bunch of material out of the inside of the neck if I didn't have to. Spinning to warm up the brass is a no go, just flat out to tight for that. Copy on not trimming before sizing. Never thought about how sizing it trues the case then ready to uniform via sizing, got it.
 
I agree, my comment was only about FL sizing. You need to use a FL die with a neck bushing so you can control the neck size. I found the stock FL dies always size the neck too small for a turning pilot on all but the thinnest brass.

Ok, I didn't realize there was FL busing dies. Only ever saw them on neck dies. Thank you for that insight. I figured I was going to have to purchase some better dies, the RCBS FL's were a christmas present to get me started. What FL bushing dies would you recommend? And also, what size neck diameter (inside) am I looking for for proper neck tension? Thanks
 
Redding has instructions for selecting bushings on their site. Basically bullet diameter+2 x neck thickness-.002. I would get at least two if not three.
 
Remember if youbuy a bushing die, buy the bushing size for after neck turning, not before, or both, after turning you ned to neck size again, becuase you've lost the tension. Sure you want to do this?
 
Remember if youbuy a bushing die, buy the bushing size for after neck turning, not before, or both, after turning you ned to neck size again, becuase you've lost the tension. Sure you want to do this?

Sure I want to neck turn? Well I figured if I was going to spend time reloading instead of buying off the shelf, I would reload as consistant as possible to make it worth the effort. Are you saying I have another option besides bushing dies that will still let me neck turn?
 
You can load pretty accurate ammo without neck turning. For my 7mm saum, I run a .312 bushing for tension, both fl and neck sizing, outside of case measures .312". I also have an RCBS x-sie, if I size my brass with it, my outside diameter still measures ..312". So who's to say you need a bushing die before? After turning, you'll need a bushing die becuase of the material you removed, you may have enough brass left there to run the same bushing as before, but is the neck tension still the same? You thinned the brass, is the pressure the same now? Or do you need to buy a smaller bushing to offset material loss, with less material the case shouldn't be able to hold the bullet the same as before, right.
 
Are you running an expander plug in your sizing die? The expander should be opening up the neck so the pilot will fit just so. You want a slip fit with no wobble factor, so it's usually not a good idea to turn them before sizing.
 
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I use K&M neck turning tools. All of them require running the cases through the proper expander before turning. Real bad idea to try to turn necks if the mandrill is a force fit.

OFG
 
OK, we do this all the time for BR rifles. Here is the condensed version, starting with NEW brass. If you have USED brass, start by sizinf DOWN the neck, then pushing a sizing mandrell thru the neck, to size it for an exact fit to the bullet you are shooting, ie no neck tension. When turning necks, the inside diameter of the neck just prior to to turning is of extreme importance, change that, everything else is off.

To repeat, "the inside diameter of the neck just prior to to turning is of extreme importance, change that, everything else is off."

OK - Step one, size neck to fit bullet - aim for EXACTLY the bullet diameter. Keep track of what expander used, that will be the one from now on.

Step two, calculate desired end point - you have to know the neck diameter in the chamber. All my BR rifles are marked with neck diameters, all but one are .265 chambers. As was stated above - chamber diameter less bullet diameter less 2x wall thicknessless clearance allowance of .002-.003. DO yo know your chamber diameter yet? Usually stamped on the reamer, BTW.

Step three, set neck trimmer - cut one case, use calipers to measure wall thickness, perform above calculation to get correct wall thickness. Lube both the inside and outside of the case, or you'll get crazy readings. I use Tap Magic, works good. You'll scrap several cases until you get it set right, sorry, that is how it is.

Step four, deburr mouths.

Step five - FL resize cases, if using a rimmed mag like 7MM or 300 WM, you'll soon need a collet die, to squeeze the case ahead of the base.

Step six, check OAL of case.

OK you're good now. When you begin to size the case, you may have to swap bushings a few times to get it right. If the bullet is loose inthe case, you need a smaller bushing. That is why the BR guys have a whole selection of bushings, to get the neck tension just right.

Also, if this is a factory SAMMI chamber, it's already pretty loose, neck turning only makes it more so. You really ought to think about whether you are doing more harm than good here.

Not to be critical, but your dad's rifle having .010 more headspace makes no sense on a belted magnum, which headspaces on the belt, not the shoulder. If it is headspacing on the shoulder, there is more afoot to be considered, before using his brass.

I find that brass from a belted mag, USUALLY needs to stay with the rifle it came out of, unless I am working the brass REAL hard and setting it back a lot, it chambers hard. Hard chamber does not equal accuracy IMHO.
 
Are you running an expander plug in your sizing die? The expander should be opening up the neck so the pilot will fit just so. You want a slip fit with no wobble factor, so it's usually not a good idea to turn them before sizing.

I am running it with an expander plug, it opens it enough to fit the trimmer pilot just right (its .280"), but the neck turning pilot is .282". The case necks are averaging .281" after coming out of the FL die with expander plug.
 
MikeeBooshay-OK - Step one, size neck to fit bullet - aim for EXACTLY the bullet diameter. Keep track of what expander used, that will be the one from now on.

Since I am using this rifle for 50% Hunting 50% non competition long range shooting, wouldn't I want a little bit of neck tension, say size necks .001" smaller than the bullet? Just to make sure everything will hold in a hunting atmosphere. Forgive my ignorance if this isn't correct.

Also, if this is a factory SAMMI chamber, it's already pretty loose, neck turning only makes it more so. You really ought to think about whether you are doing more harm than good here.

COLOR="#0000CD"]I wasn't looing to shave so much so that I was going for a custom fit to my chamber. I don't have the means to measure that besides measuring my fire formed from my rifle. Just looking to shave 50-75% of the circumference of the neck so the neck is accurately the same thickness so the bullet has the same tension all the way around. "Conisistancy case to case".[/COLOR]

Not to be critical, but your dad's rifle having .010 more headspace makes no sense on a belted magnum, which headspaces on the belt, not the shoulder. If it is headspacing on the shoulder, there is more afoot to be considered, before using his brass.

I don't know how to answer that. His fire formed Sako brass in my RCBS Precision Mic measured .008" longer than the fire formed brass from my howa. Obviously there was a machining difference company to company there.

I find that brass from a belted mag, USUALLY needs to stay with the rifle it came out of, unless I am working the brass REAL hard and setting it back a lot, it chambers hard. Hard chamber does not equal accuracy IMHO.

Once I pushed his shoulders back -.002" than my fire formed brass, they chambered as easily as a factory round in my gun. The brass will stay with this rifle from now till it's worn out. He just had 300 brass to my 30 to get me started so thats what I did.
 
MikeeBooshay-OK - Step one, size neck to fit bullet - aim for EXACTLY the bullet diameter. Keep track of what expander used, that will be the one from now on.

Since I am using this rifle for 50% Hunting 50% non competition long range shooting, wouldn't I want a little bit of neck tension, say size necks .001" smaller than the bullet? Just to make sure everything will hold in a hunting atmosphere. Forgive my ignorance if this isn't correct.

Also, if this is a factory SAMMI chamber, it's already pretty loose, neck turning only makes it more so. You really ought to think about whether you are doing more harm than good here.

COLOR="#0000CD"]I wasn't looing to shave so much so that I was going for a custom fit to my chamber. I don't have the means to measure that besides measuring my fire formed from my rifle. Just looking to shave 50-75% of the circumference of the neck so the neck is accurately the same thickness so the bullet has the same tension all the way around. "Conisistancy case to case".[/COLOR]

Not to be critical, but your dad's rifle having .010 more headspace makes no sense on a belted magnum, which headspaces on the belt, not the shoulder. If it is headspacing on the shoulder, there is more afoot to be considered, before using his brass.

I don't know how to answer that. His fire formed Sako brass in my RCBS Precision Mic measured .008" longer than the fire formed brass from my howa. Obviously there was a machining difference company to company there.

I find that brass from a belted mag, USUALLY needs to stay with the rifle it came out of, unless I am working the brass REAL hard and setting it back a lot, it chambers hard. Hard chamber does not equal accuracy IMHO.

Once I pushed his shoulders back -.002" than my fire formed brass, they chambered as easily as a factory round in my gun. The brass will stay with this rifle from now till it's worn out. He just had 300 brass to my 30 to get me started so thats what I did.

OK I'll try to answer these in order.

Yes, you need neck tension, there are several ways to get it. If you are using an expander button, those don't work as well with a bushing type die. What happens is you are sizing the neck too many times, and not getting consistent results. The expander ball enters the neck first, opening it up to the ball size. Then the neck hits the bushing, squeezing it down. Then you withdraw the plunger, and pull the ball back thru, opening it up again. You have to pick one, either the ball or the bushing to get consistent results. I like and prefer the bushings, because changing it is easy, I have to make a new ball for the expander.

Think of what happens in the chamber, cases expand to match the chamber, then relax after pressure dies off, but still are larger than when they started. No need to expand the neck we just need to restore neck diameter to hold the bullet and assist with building pressure, before the case releases the bullet. A bushing can do all that, without the ball.

You are on the right track, seeking consistent neck tension, you won't need much neck trimming though with a SAAMI chamber, it WILL be loose. The main thing is to try and get even, consistent wall thickness around the neck. If this were a BR gun, with a tight neck chamber, we would try to get the wall thickness less than .010, you can measure it with calipers. You'd make your first bushing try, using .284 ( bullet dia ) + .020 ( twice the wall thickness ) + .002 or .003. - likely a .306 bushing. But.... you have to play with it, the cases have a bit of spring to them, you may need as small as .300 to get the final size you need.

For example, I have a favorite BR rifle, 6MM PPC, has a .265 neck. Bullet is .243, cases are turned to .009-.010 MAX!!! You'd think I need a .262 bushing, but the only way I get any real neck tension, is to use a .260 or smaller. Neck measures .263 when round is ready for chamber. Bullet seats easy in case, not tight, if I go long, into the lands, it just pushes back in the case, not really optimal if it was mag fed repeater. Just info for you to consider.

On the brass from dad's gun. His CHAMBER is longer, but headspace on the 300 WM, is set by the belt. A HS gauge for the belted mags is only an inch long, no neck or taper, just case head and belt. Thats why different rifles don't swap cases so well.

One last thought - you'll get more results from watching the run out of your rounds than anything. Cases are not true as new, do some neck turning and you'll see what I mean. Use fired cases, true the necks, and get the bullets in them as straight as possible, keep them straight. Groups will shrink.

That and a new barrel ( barrels and bullets are where accuracy are from ) and you will be GTG. Hope this helps,
 
I have the same tools and had the same problem until I ready one of the helpful hints in a Sinclair catalong some time back that said to run a expander die thru the cases after resizing to make sure the necks were the rights size. This is the way to do it. And lube your necks when turning too
 
I have the same tools and had the same problem until I ready one of the helpful hints in a Sinclair catalong some time back that said to run a expander die thru the cases after resizing to make sure the necks were the rights size. This is the way to do it. And lube your necks when turning too

Got a K&M Expander on the way, with a little luck that will have me back up and running. Thanks