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Old 04-21-2019, 09:54 PM
Oso Polaris Oso Polaris is offline
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Default Bushing Size / Neck Diameter for 17-222

I have a couple of question related to case forming. I am starting with 223 cases to form 17-222 cases.

Case preparation of the Neck:
1. Which activity goes first - Ream the inside of neck or neck turn the outside?
2. at what point in process of forming case do you neck turn and/or ream? Is this done only after final case forming is completed or is it done at different stages during case forming, such as outside neck turning after sizing down to .20 caliber to avoid doughnut buildup before sizing down to .17 caliber

Neck Tension / Bushing Size:
Neck diameter is 2.065" as measured from fired case in my 17-222. For the intermediate .20 caliber step-down I will be using a Redding Bushing FL die in .222 Rem with .228" bushings, and then following up with RCBS Forming Dies in .17 caliber.
1. Assuming that case neck's has sufficient thickness to require neck turning, what neck diameter would be target/ideal based on my chamber... 0.204"???
2. What size bushing should I be considering for final step (.202")? Or is this something that I will have to determine only after forming some cases?

Thanks

Last edited by Oso Polaris; 04-22-2019 at 02:08 AM.
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Old 04-22-2019, 02:35 AM
trotterlg trotterlg is offline
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I would do all the sizing, inside neck ream and use an expander rod to set your final inside neck size. If you don't use an expander ball the neck tensions will be different as your neck brass thickness changes after several reloads. I have a 17-204 and just size the neck down in one pass and shoot it.
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Old 04-22-2019, 04:38 PM
Oso Polaris Oso Polaris is offline
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Default Newbie needs Insight - Overview

OK - Not getting a lot of feedback on my original question. I have read plenty of threads and thought I would finalize my process and gear before jumping in hard. For a newbie the distinction of reaming versus neck turning and the timing of these two activities can be intimidating/overwhelming. Let me try re-phrasing my ignorance.

As I form cases from .223 (donor case) into .17-222, I will be thickening/building-up brass at:
1) Shoulder/neck junction as I bump back the shoulder, which from what I read is main culprit in formation of doughnut on exterior case as the brass has to go somewhere when expander ball comes back through the neck.
2) Neck walls thicken during sizing down to .17 caliber, which way result in opening being too narrow for the bullet to fit inside the case or collapsing the neck as I try to force expander ball into case.

Question: After sizing down a case, when would you ream the neck... only when the expander ball/bullet will not easily fit into neck?

Question: Is there any benefit to reaming the neck for uniformity on newly formed cases even if the expander ball could be made to fit or is this redundant because the expander ball adequately perform this role?

Neck turning is performed to create uniform exterior (improves neck tension consistency) and/or to provide sufficient space for the case to fit inside the rifle chamber.

Question: When is best time to neck turn the case … only after sizing down to final cartridge or at some intermediary step in sizing down process?

Question: Does it matter the order of performing neck turn or reaming?

Question: Even if case fits inside the chamber, should I lightly neck turn (skim cut the exterior for uniformity)? This final diameter will dictate the bushing size for final sizing.


Thank you for any insight and advise.

Last edited by Oso Polaris; 04-22-2019 at 04:43 PM.
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Old 04-22-2019, 06:39 PM
Daryl Daryl is offline
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I'll try to help.

Proper cerosafe cast of the chamber to find chamber neck diameter.
Neck dia. minus .175" (bullet dia. .172" + .003" expansion (.0015" per side)) = double neck wall thickness. Divide by 2 = neck wall thickness per side.
Thus example: .196" chamber - .175" = .021" divided by 2 = max. case neck = .0105" neck wall thickness for turning (not reaming).

Inside Reaming leaves neck wall irregularity while turning 'trues' up all thickness.
A neck wall thickness mic. is pretty much necessary for measuring neck wall thickness accurately.

Neck sizing bushing will depend on your final neck dia. with bullet seated - .002" to .003". I like .002" which is .001" per side button size. Wilson bushing I/D's are .0005" tighter on the stamped end.

Someone correct me if I am wrong or have things mixed up or overcomplicated. It's been a while since I made brass for an oddball ctg.
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Old 04-22-2019, 06:56 PM
Oso Polaris Oso Polaris is offline
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Quote:
Originally Posted by Daryl View Post
I'll try to help.

Inside Reaming leaves neck wall irregularity while turning 'trues' up all thickness.
Thank you. Can you clarify how reaming leave the walls irregular? I thought that Reaming creates a centered, uniform hole in the neck. Are you referring to the exterior wall remaining uneven/inconsistent, which can only be corrected by neck turning? Thanks
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Old 04-22-2019, 07:29 PM
L.Sherm L.Sherm is offline
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I'll try and give this a shot. I'm not a fan of inside neck reaming because it leaves a very rough finish and I believe you get galling of the bullet to the inside of the brass. Seat a bullet on a inside reamed neck and the pull the bullet and see if it's all scratched up that's what happened to me when I tried it about 10-12 years ago.
I use a K@M kit know with the cutter on the mandrel to take any donut out that might accrue. I have forming dies that I use to neck down brass then anneal after forming down necks then before i FL size and pull the expander through to push all the imperfections to the outside. After this step is when i outside neck turn if theres not enough clearance to fire the first time. I believe after the first firing it helps to push the imperfections to the outside of the neck.
If you have to neck turn before firing what helps is to go .0005 less than your desired dia and fire once then take .0005 off to your final dia.
I do this only on some of my LR hunting rifles that I'm after ultimate accuracy. It all boils down to your end goal and if you are willing to spend the time neck turning.
I hope this helped to answer your questions.
The K@M is and awesome kit for turning necks, I can get .0005 of runout on a turned FL sized case consistently.

Last edited by L.Sherm; 04-22-2019 at 07:31 PM.
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Old 04-22-2019, 07:52 PM
Oso Polaris Oso Polaris is offline
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Sherm - Thanks!!! I had bought the 21 Century Neck Turning Lathe. I was contemplating their new "3 Way" Trim Attachment that simultaneously reams, trims to length, and chamfers the case

http://www.xxicsi.com/3-way-trim-attachment-.html
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  #8  
Old 04-22-2019, 08:52 PM
GrocMax GrocMax is offline
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Be sure any primer pocket flash hole trimming is done first, nobody makes a (cheap) tool to fit inside 20 or 17 cal necks.
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Old 04-22-2019, 10:47 PM
trotterlg trotterlg is offline
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If you do all the sizing without an expander, then inside neck ream you remove the doughnut from the inside of the case instead of pushing it to the outside to remove it. Don't know what you are using to inside neck ream but I have always found a good reamer to leave a very nice finish. Outside neck turning will get you a uniform wall thickness if it is a problem.

I would size to about .020, then to 17, inside neck ream, expand to size and trim.

This is a 14 TCM done this way in 4 steps from 22 to 14
There are probably a hundred ways to get where you want to go, just don't over think the problem.

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  #10  
Old 04-23-2019, 02:40 AM
Gary in Illinois Gary in Illinois is offline
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Default Case forming

I can’t tell you the “best” way to form cases but I can tell you how I do it. Some of this will vary depending on many things: the case you start with, the softness or hardness of the brass and the case you expect to form to in the end.

1) If you can form the brass without damage before annealing, do so. You should end up with a neck that is too small in diameter to allow a bullet to be seated.
2) Anneal the brass
3) Trim cases to a uniform length slightly longer than the final desired length
4) Run the case necks into the K&M neck expanding mandrel
5) Outside neck turn the brass to a diameter that will allow a seated bullet to chamber with .002” chamber clearance using the K&M neck turner with the neck turning pilot that also cuts any excess material (donuts) from the inside of the case neck while neck turning.
6) Full length size case, load and fireform
7) Trim case to ~ .005 less than chamber length

You will notice that I use K&M tools throughout the entire process. While I happen to like the K&M tools, the important thing is to use the same brand of equipment throughout because the expanding mandrels and pilots are all sized to the proper diameter for use with the rest of their tools.

As mentioned above life will be easier it you deal with the inside uniforming of flash holes before starting the case forming process.

The above is only a general guide; many times annealing must be performed at some point during the forming process.
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