Home Forums Reloading Big Game Rifles How can I get good necks?

How can I get quality results with a practical method to prepare brass case necks and mouths? Should I use bushing dies? Mandrels? Neck turning? Reamers?

I have a few hundred Starline brass for a cartridge that uses .264" bullets. When they come out of the bag brand new, the mouth is slightly rolled in:


Brand New Brass from the Bag

...and the diameter is fairly tight so that neck tension ends up about 0.004". I lightly chamfer it, load it and fire it.

Once fired in my rifle's chamber, the necks are 0.011" oversize. I have a bushing that nominally should bring them down 0.010", but because they're being squeezed quite a ways, they come out 0.012" smaller or 0.001" under (in other words, bullets will seat with 0.001" tension). Redding indicates to expect this:

"It has come to our attention through customer calls and our own use of the bushing style sizing dies that in certain instances, a given neck sizing bushing will produce a case neck diameter that can be several thousandths of an inch smaller than the actual diameter of the bushing. This idiosyncrasy occurs when the neck diameter of the fired case is a great deal larger than the diameter of the neck sizing bushing, such as occurs when factory chambers are on the large side of the tolerance range and the brass is on the thin side. Typically, we have not noticed any problems until the case neck is reduced more than 0.008-0.010". Solutions include, increasing bushing diameter to compensate and/or the use of a size button. Reducing the neck diameter in two smaller steps by using an intermediate diameter bushing will also help."

Because I am using a bushing that is 0.010" smaller than the expanded neck, it is actually reducing the neck by 0.012". I selected this bushing because 0.001" neck tension is what I wanted. Unfortunately, I have found that 0.001" neck tension is insufficient. So I bought another bushing that is 0.002" smaller. I found that it will give me two or three thousandths neck tension if I use it on a fully expanded neck.

After a couple firings the mouth is pretty well rolled in.

Reloaded a Few Times

I do wet tumble the brass, but for no more than 30 minutes. I have a RCBS carbide chamfer tool, but to cut the whole rolled edge out I would have to chamfer it all the way to the outside edge of the mouth and then some. I would pretty much have to trim the whole mouth off the neck to get rid of the rolled edge. The necks are well under the maximum length though, about the minimum actually and I don't want to trim.

I decided to ream the inside of the neck. I have an 11/64th drill bit that measures exactly .264". So I resized the necks with my larger bushing and reamed the necks with the bit. I did it by hand with just my fingers. I wasn't removing a lot of brass, mostly the rolled edge.

I found after reaming the inside of the necks that the rolled edge was removed, but then there's a gap of untouched brass just below the mouth chamfer where the neck appears bulged, and then the reamer polished the inside of the neck below the bulge. Is this bulge from seating the bullets?



Reamed and Chamfered

Unfortunately, after reaming the inside of the necks and then resizing them with my smaller bushing, I don't have enough neck tension. If I was resizing from a full expanded neck, I probably would have enough tension, but since I reduced the neck in two-steps, they are the nominal diameter of the bushing instead of a couple thou under.

I'm thinking of ordering another bushing, but I'm pretty dismayed about these necks and I'm wondering if I'm going about this the right way.

My goal is is high quality brass and cartridges capable of true, consistent 1 MOA accuracy for practice and hunting medium game in the 200 to 300 yard range. I'm not trying to get bench-rest accuracy or shoot very long range. What do I need to do?

Should I be starting with different brass? Nosler, Lapua?

Should I undersize the neck OD and then use a mandrel?

Do I need to turn the necks?

Should I ream the necks with something like a Forster neck reamer? Should I ream before resizing with a standard reamer or after resizing with a wildcat reamer?

Holy du ck. Why not just use a regular ol RCBS fl sizing die and be done with it? No need to overcomplicate chidt. New brass gets ran through the sizing die, checked for proper length and then chamfer the inside and outside of the neck. Fire and then repeat the process. Starline makes damn good brass. Theres no need for a mandrel this or bushing that. Especially if you are talking moa accuracy. However, if the brass is a problem, id contact starline.

Lee Collet Die unless it is a very unusual cartridge. Chamfer when new. Anneal every 4th firing. Trim and rechamfer as necessary.

Starline is indeed good stuff.

For your stated goal of 2-300 yard 1 MOA accuracy I think you are way overthinking this. I agree that a 25$ RCBS FL sizing die setup to bump the shoulder back 2-3 thousandths should be more than adequate for what you are looking for. I personally don't think that the brass brand matters that much as long as you keep it grouped together as per times fired. I will say that annealing after a few firings will help with the neck tension returning to the original value. Don't complicate things by adding additional variables. If you can't get the accuracy you are looking for with basic loading tools and processes try a different powder (or charge weight, or bullet, or seating depth).
Good luck

This is approximately what I do.

I ordered a collet die yesterday. I think I was mistaken in trying to size the neck for a precise amount of neck tension without regard to the concentricity and the straightness of the neck. Because I was sizing down as much as .012" from a .300" chamber in one step and was not even touching the necks with the expander button, my necks are a mess. It would seem the neck bushings and dies are best suited to turned necks in a chamber reamed tight for turned necks. From my SAAMI-spec chamber, I could try to minimize runout by sizing down in three steps using .295", .290", and then .286" bushings. The brass in the neck is 0.012" thick, so at that point ID would be 0.262" (assuming no spring back which would require a slightly smaller bushing to achieve 0.262"). 0.262" is the diameter of the expander button, so it should just touch the neck at that point. This three-step process would minimize the runout as best as possible using bushings with my given chamber. However, I think a Lee Collet Die is a more straightforward path to a concentric neck and consistent neck tension.

This is generally my routine as well. Lee will make you a custom collet die for unusual cartridges. Worth the money.

I agree with others. Size, trim to length and chamfer. The Lee collet die eliminates the need for lube which I perfer but you can get good results with a FL sizer. If you are talking hunting loads and not BR you should be good to go.

Juniper, Have you figured out why you're getting that lip on the inside edge of the case mouth? A deburring tool should remove it, but it shouldn't return unless something else is going on. I'm wondering if tumbling is the cause. Maybe try not tumbling for a few loading cycles to see if that fixes the problem? No matter what the marketing types tell you; blindly throwing more $$ at a problem without knowing the cause, while making the loading tool manufacturers happy, may or may not fix the problem. Everybody gets lucky sometimes, but not much is learned & we end up with a pile of unused stuff in the drawer. Ask me how I know this.

No mention of the firearm? A mystery 6.5 of some flavor? With a standard factory chamber, regular FL dies of good quality should be all you need to reach your MOA goal as long as the rifle & shooter are capable. Personally, I try to stay away from dies in red boxes... except Forster. Watch out for that loose screw behind the trigger too. It can (& has) happen(ed) to us all.

The lip is there from Starline. See the first picture. That's how it comes from the factory. I believe the mouth is rolled like that because of peening when the cases are tumbled together -- in the bin at the factory, and in the bag they package them in. Any tumbling is going to peen the mouths progressively worse. For the same reason that Starline does not package each individual case in a separate compartment and protect the mouth, I also handle my brass in bulk piles. It gets piled in Akro bins, it gets dumped in and out of buckets, and worst of all it gets tumbled in a tumbler. As I wrote earlier, I wet tumble my brass a minimal amount, typically 15 to 30 minutes at the most. That is enough to clean it without peening the mouths excessively.

While I believe bulk handling is a significant cause of mouth peening, there are other factors that cause the rolled edge of the mouth. If I ram the mouth into a bushing (or any OD sizing die) the front edge of the mouth will bend in first as the mouth is squeezed first and then the neck. Unless a mandrel is pulled back out of the neck to straighten that edge after the bushing crushes it, it will just stay rolled. To get the Redding mandrel to pull the mouth back out, the neck would need to be sized down farther than I have been squeezing it.

I get the same rolled edge on my handgun brass, for the same reason -- tumbling and outside-only forming. There is simply no process that I use that flattens that inside edge other than firing cases. Tumbling, resizing, and crimping all roll it in. Firing is the only thing that pushes it out.

The rolled edge can be cut off with an inside chamfer tool, but the more the edge is chamfered, the more it is thinned and that makes it easier to roll the edge another time.

Just a guess here, but is it possible that he is using a die with crimp feature adjusted so that as the brass gets longer from firing that he’s hitting the first step of the crimp and rounding the necks?

That is why i trim all my new brass to length.

It does away with any irregularity in that area and it makes them all the same size.

I don't crimp the rifle brass shown nor do I own any crimp die for it. I do crimp revolver brass, but with a dedicated crimp die, not the resizing dies. It is the bullet seater that has a crimp built in, but I don't use that, in fact I use a seater that does not have a crimp.

I think trimming brass for uniformity can be a good thing, but I'm wary of trimming necks on bottle-neck rifle brass excessively short. As long as they're not touching the end of the chamber, and they're all the same, the longer the better. It is, after all, what holds the bullet in position prior to launch. As it is, it would have to stretch fifteen thou before it would be too long. The Starline brass comes new from the factory about eight thou under the SAAMI maximum spec and my used brass is fifteen thou under after several firings, resizings, and chamfering. Therefore, I am not inclined to trim it even shorter.

I suspect more people will find their case mouths rolled in if they look. Whether they're rolled or not, photograph them and show them here for the sake of discussion.

I just use it to trim them and have a sharp edge.

Not really taking much off.

Looks like they have been tumbled. Simultaneously turn and ream, then trim.

Do you tumble cases?

Do you turn them?

Do you ream them?

If you do anything of these things, how do you do it? What turning fixture do you use? Do you use a Forster reamer? The standard or wildcat (before or after resizing)? Once you turned and reamed, how do you set the neck tension on your cartridges that have been turned and reamed?

You could buy a 0.001" larger bushing.
Or try a brand of brass reputed to be a tad thinner.
Or polish the unside of the bushing

Welcome to the campfire! Something to consider, since you already have the bushing die and have ordered the collet die is that they can be used in tandem. You can use the collet die for sizing the necks very concentrically and bump the shoulders as needed with the bushing die minus the bushing.

You can also size the necks to your desired diameter, plus 2 or 3 thousandths with the collet die and then use your bushing die for the final neck sizing and shoulder bump operation with a bushing installed and the expander removed. This can work very well if your brass has uniform neck thickness and provide repeatable and consistent neck tension and concentricity in my experience with a
.308 Win.

I have a separate body die to bump the shoulder. My bushing die is neck-only. I do intend to try to use both the neck bushing die and the collet die to the best effect. I'm not sure I understand how the collet die could size the necks to a specific diameter. That is the virtue of the bushing die. I suspect the collet die will squeeze the necks down on to a mandrel that results in a bit too small an ID, but maybe it will be just right. I would have to enlarge the mandrel somehow to have it two or three thou over the goal diameter. I considered using the Sinclair mandrel die and carbide mandrels, but these don't give the concentricity benefits of the collet die. So I rather expect to get the concentricity and uniform neck wall straightness from the LCD, and I will have to see if I can find any benefit to using the bushing die. It seems it would have an obvious benefit if my chamber wasn't expanding the necks so far so that the bushing did not need to squeeze them down more than 0.005", and if the necks were already concentric and turned. Perhaps I will find a benefit to it even with fewer criteria, even if it is only that it works the brass less when I use it every other or every 2nd and 3rd resizing. I just annealed all the necks on my used brass today. I had not done that until now, and some of the brass has been reloaded four or five times.

You're making this way too hard.