Run-out issues with Redding Bushing Neck Die

[mjphawk]

I recently added a RCBS concentricity gauge to my reloading collection. I was getting about 0.003 average run-out on my completed ammo.

I am loading 308 Win with Lapua brass. I do not turn my necks.

I decided to measure each stage of my process to see if I could figure out where the run-out was being induced.

• Un-sized fired brass: 0.000 - 0.001
• Body sized in Redding Body Die: No additional induced run-out
• Redding Bushing Neck Sized: 0.003 - 0.004
• Bullet seating: No additional induced run-out

I tried the following with the neck die to see if it improved results

• Different bushing (0.337 & 0.338): No improvement
• Allowing the die to "float" in the press: No improvement
• Adjust how far down the neck the busing re-sizes: No improvement
• Lee Collet die instead of bushing die: 0.001 total runout (nearly completely fixed issue)

I suppose the easy answer is to just use the Lee Collet die but I like having the ability to control my neck tension.

I don't want this to be a bushing die vs collet die discussion. I am really just looking for fix my issue since I know both are capable of producing nearly perfect ammo. Any suggestions would be greatly appreciated.

 

[dannySH]

Looks like a possible die misalignment. Put a rubber O-Ring on the underside of the die locking ring. This allows the die to self-align itself to the case.

 

[padom]

Try bushing neck die with and without expander?

 

[TheGerman]

Are you bottoming the stem out on top of the bushing, or are you allowing it like 1/4 a turn space? Didn't read that the first time I used it and was getting weird results. Not only is the die to be free floated, but the bushing inside needs a bit of space between it and the top of the stem to free float and center itself.

 

[padom]

I was seeing .003-.006 run out with a bushing die when not using the expander.

 

[mjphawk]

Thanks for all of the input.

Regarding the use of the o-ring, I didn't use an o-ring but I did back the die out by 1/4 turn to try and simulate the affect of the o-ring had I used one. It would seem to me that this would accomplish the same thing by allowing the die to index itself before bottoming out on the shell plate. Clearly this wouldn't be a "solution" long term since the die could also walk in or out and change the depth. It didn't seem to have an impact on the result I was getting. Should I try running the test again with an o-ring?

I tried with both the expander in and out. With as little as I am sizing the neck the expander barely kisses the inside of the neck. Result were the same both ways.

I went back through and ensured my adjustments were in accordance with the instructions. I don't think I was mis-adjusted but will test again to be completely sure.

Padom, regarding a level of "acceptable" run-out, did you notice any negative impact on accuracy at 0.003 - 0.006 of run-out? I'm not an F-Class shooter, but most of my practice is from a bench and shooting for groups so much of my focus is on fundamentals and reloading technique to try and close groups up as much as is possible. I then get to test out the training at a 1,000 yard range only a few times a year (nearest 1,000 yard range is 3+ hours away).

 

[Dave62677]

I experienced the same issue as yours last year. I upgraded floating die press, still excessive.005 runout on the neck. My buddy who load 6.5cm with neck bushing die result with .001-.002 neck runout with COAX press. I can't figure out how to reduce my 308 neck runoff with redding bushing die. I turn neck on the brass still around .005 runout. I did gave up and go with lee collect. My avg reload neck runoff .001

 

[mjphawk]

I experienced the same issue as yours last year. I upgraded floating die press, still excessive.005 runout on the neck. My buddy who load 6.5cm with neck bushing die result with .001-.002 neck runout with COAX press. I can't figure out how to reduce my 308 neck runoff with redding bushing die. I turn neck on the brass still around .005 runout. I did gave up and go with lee collect. My avg reload neck runoff .001

Thanks for info. Do you think the 0.005" run-out was limiting your accuracy potential?

 

["Partridge"]

I set the bushing to float within the die. Which you did mention. Also make sure that the shell holder or brass in the shell holder floats freely. And lock the die down tight.

 

[918v]

You can vary neck tension in the Lee collet neck die by using different diameter rods which Lee sells for $10.

 

[padom]

Funny enough, I tested my Lapua brass sized with my Forster FL sizing die that showed .0005-.001 run out and the same brass with same load sized with Redding neck bushing die that showed .004 runout.... zero accuracy difference

Both produced single digit SD's and 5 shot groups in the .3's in my Bartlein 260rem.

 

[flyright]

I ran into this issue with a Redding bushing die a few years back. I tried floating the die, extra floating the bushing, expander in/out and it was very frustrating. I then borrowed a friend's Redding die and the problem disappeared. I got my die replaced and problem was solved. Just my .02...

 

[Milo 2.5]

Just out of curiosity, are you going total indicated runout, or cutting that number in half? I remember measuring once, flipping out because runout was .006", I switched dies, and press, runout improved, but accuracy downrange did not. Then 3 yrs later did another die brand switcheroo, all it ever did was cost me money, especially the concentricity gauge.
If you are going to mess with shit, you owe it to yourself to find out what it does for you.

 

[Dave62677]

Thanks for info. Do you think the 0.005" run-out was limiting your accuracy potential?

Honestly, I really don't know. I think is more like mental game. My reload with .001 runout avg .4 ish moa with 5 shot. Best was .29 moa

you gotta see for yourself. Anyone can claim anything on forum. Maybe your bbl don't care that .005 runout after all

 

[Nemsis]

Send your die back to Redding they'll make it right

 

[918v]

A very long time ago I realized that sizing the neck down using a bushing die in large increments, more than .003", induced runout. I arrived at this following a test where I sized a neck in .001" increments and measured runout. After that I went with Lee collet neck dies for everything.

 

[Steel head]

How many thousandths is the bushing working the neck down?

over .004 and you may need a two step process or run a collet die like I do(and now you see why) and not have monkey about with it.

 

[Steel head]

A very long time ago I realized that sizing the neck down using a bushing die in large increments, more than .003", induced runout. I arrived at this following a test where I sized a neck in .001" increments and measured runout. After that I went with Lee collet neck dies for everything.

My results were similar

 

[TripleBull]

I measured concentricity on new Lapua cases recently, gently mandrel-ed the necks then sized them with a Redding bushing die. On average, concentricity improved by about 30 to 50% across the lot. The concentricity of about 1/4 of the cases was unchanged and this did not correlate with the original runout measurement.

 

[SPAK]

What is your fired case neck OD? Sizing down any more than .004-.005 will induce runout with bushing dies. Custom honed Forster fls dies give me the best run out results. Neck turning does help but isn't necessary.

i usexto "fix runout" of anything more than .005" TIR.

I no longer do that nor do I get concerned with anything .005" TIR or less. I've not seen any difference downrange...