Another bushing question - need your expertise

[poli]

Hi everyone, great forum with lots of good info. This is my first post - I’m new to reloading and for the past few weeks I’ve been reading a lot about dies and about finding the correct bushing for the Redding dies. I have a 22-250 Browning A-Bold Medallion with BOSS and if I do my part, I’m getting under 1” groups at 100yd with Remington Premier AccuTip V 50gr BT. I do mostly target shooting and my goal is to get the best accuracy that the gun and myself are capable of. So, I went ahead and purchase the Redding Match die set and a .248 bushing – thinking that if I’ll turn the neck this bushing will work well. The OD of above mentioned loaded cartridge measures between .2510 – .2515. The OD of the fired cartridge measures .255 – .256 (for reference only – I know that it doesn't play a deciding factor in calculating bushing dimensions).

I ran some brass through the Type S FL resizing die and I got the following results:

- with expander ID = .222
- without expander ID = .220

I then seated a bullet into the brass with .222 inside diameter using my Reading Competition die, but I have a feeling that the bullet was a bit forced since the die left a circular mark on the bullet where it made contact. I can also see a bit of cooper at the mount of the brass as if the edge of the mouth pealed off a bit from the bullet during the seating process (I hope it makes sense). Is this normal?

I was getting ready to buy the .250 bushing but first I wanted to consult Redding, so I called them and talked with a technician who told me that my 0.248 bushing should be ok!!! Then he said that 0.249 might be a better choice… Their web site says to get a bushing .001 smaller than the diameter of a loaded cartridge, yet their tech guy tells me something else. What do you guys think?

I was planning to get a 21Century neck turning tool, but the I started thinking: should I get the tool, turn down the neck and use the .248 bushing? If in theory I’m turning down the neck by .001 - .002 then my final OD for a loaded cartridge should be around .249 - .250. Assuming that my rifle neck diameter is .256 (from the fired ammo dimensions), isn't the .006 - .007 difference between a loaded round and my rifle neck diameter to big? The other option is to forget about turning the neck and get the .250 bushing. In this case the difference between a loaded round and my rifle’s diameter will be only .004 - .005. What is your opinion? Everything else being equal, which option would give me a better accuracy?

And this is just for 22-250; then I’ll have to decide on some bushings for my 308 as well

 

[BoydAllen]

What kind of measuring tools are you using? Generally speaking we work with neck thicknesses measured with a micrometer that has been designed for this task, that measures to .0001, and for ODs a 1" micrometer that reads to the same. Measuring neck IDs with your caliper is not accurate. If you want to measure what we commonly call neck tension, you will need to measure the OD of a sized case neck, and that of the neck of a loaded round, and subtract to find the difference. Unturned case necks are tapered, (as are the chamber necks of most factory chambers), so it is important to measure neck thickness and OD the same distance from case mouths.

Next, while we are on the subject of measuring tools, how are you setting up your FL die for shoulder bump? The best way to do this is with some sort of caliper attachment that acts as a comparitor. Hornady sells one that they call a headspace gauge, which is misleading labeling since it is a comparitor, but it is a good tool nevertheless. If you are using good brass, turning necks may not accomplish much for accuracy, and I am not much of a fan of neck sizing, so we are back to your type S FL die. It has the option of using an expander which can be just fine if the bushing is such that you BARELY feel the expander pass through the sized neck. With your die set up this way, cases should be straight and you neck tension should be good to go. Also, whatever you do, do not clean out all, or even most of the powder fouling from the inside of your case necks. Leaving a coating of it in the necks will make bullet seating and pull forces more uniform, and it will reduce the probably of what has been called cold welding of bullets in case necks. Once you have this part of reloading set up so that it works, we can move on to setting up your seating die, and working up a load, but this should keep you busy for now. If you can afford one, a concentricity gauge is a good tool to own, and if you want to be able to measure cases and loaded rounds, the one that Sinclair sells is a good one.

 

[searcher]

The shavings you describe make me think you might not be chamferring the inside/outside of your necks quite enough.

Also, pull your seating die apart and put the tip of one of your bullets into the seating cone and ensure that it is compatible with the bullet shape you are using. Most often, new/newer dies have sharp and sometimes slightly rough machine edges where it touches the bullet when seating. I would break the rough/sharp edge with some extra fine steel wool or 400 grit wet/dry sand paper. That should eliminate the "ring" you are being left with on your bullets. The reduced seating tension once your start turning will also reduce the "ring".

When it comes to "which exact bushing" to get, I've had to make reorders so many times in needing another size bushing - I order three right out the gate when getting a new caliber. I start with the largest I think I can use and go down from there. Nice just to have it and try some tension changes to tweak a load or have that next size down in the event of a slight overshave on the neck for the bushing on hand.

The .001"- under bushing recommendation is pretty "standard" with lots of folks - but it may not be what works with your load. A LOT of my best loads and those of my friends come with more tension. Never hurts to have some options in testing...

 

[poli]

What kind of measuring tools are you using?

I was using a Mitutoyo Absolute Digimatic caliper. I borrowed a micrometer from a friend and measured approximately the same dimensions for the OD of the loaded round (.2509 - 2513) at about half way between mouth and neck. The ID of the sized case (measured with the caliper) is .249 - .250 – obtained with the .248 bushing – so if I understand correctly the neck tension is about .001 - .002.

On my wish list I have a Redding Case Neck Concentricity Gage or a Mitutoyo Tube Micrometer (I don’t know yet which one I should get) and an 1” micrometer; I was also planning to get an H&H Industries concentricity gauge (http://www.benchrest.com/hnh/index.htm) but I’ll check the one Sinclair sells… oh man, I thought photography was an expensive hobby; I might have to sell some of my lenses to cover these expenses...

Next, while we are on the subject of measuring tools, how are you setting up your FL die for shoulder bump?

I have the Hornady headspace gauge and I used it to set up the FL die for shoulder bump. That was another learning experience: my headspace dimensions were all over the map on the resized brass, but I did some research and found out that that my inconsistency was probably caused by the expander which was pulling the shoulder back pretty hard (I could feel it). I removed the expander from the die, resized some brass and consistency increased to within .001; but then the ID of the neck went down by .002 to .220 which I believe gives me .004 of tension on the bullet (I used a .248 bushing). I've seen in a video how David Tubb polished down an extractor and he recommended that approach. I was going to do the same thing with mine and take it down by .001. Is this advisable?

I used some one time fired brass and I didn’t clean the fouling from the inside of the neck before resizing; I deburred it and chamfered it just a bit, used lube on the outside of the case and neck; no lube on the shoulder.

The shavings you describe make me think you might not be chamferring the inside/outside of your necks quite enough.

Truth be told, I only chamfered the inside of the neck a bit. I watched the Precision Reloading For Accuracy by Richard Franklin where he’s saying that he never chamfers the inside of a neck with a chamfering tool. He’s using only steel wool to chamfer the inside mount of the case.

I will take the die apart and work on the seating cone. As far as the bushing selection, I was trying to get away with one only - at least in the beginning, but apparently this isn't gonna happen .

 

[BoydAllen]

IMO you would do well to stick to evaluating neck tension by measuring the OD of necks of sized cases, and the same cases loaded. You can get an idea of average neck thickness of unturned necks by subtracting the diameter of the bullet, from the diameter of the loaded neck. Calipers are not the correct tool for measuring IDs and they are not sufficiently accurate to do a good job of looking at ODs, and their measuring surfaces are not properly configured to accurately measure them. I would abandon all references to ID given your method of "measurement". The good news is that you do not need them. The change in the OD will suffice. It is common for shooters to over estimate what their digital calipers are capable of. Part of the reason is the 5 or a 0 in the fourth place after the decimal. They are no more accurate than a dial caliper. Decent 1" mics, that can be read to .0001 are not that expensive these days, thanks to imports, although I would stick to the intermediate price range in these. As to a tubing mike, that is not the best tool for necks. A ball mic is much better.