runout in 308

[palo]

Hi
My fired 308 win case necks measure .344 and I have to size them to .336 for reloading.
I have a hornady bushing bump die and a redding competition neck die.
If I size the neck in one step with .337 bushing I get .336 but I get runout of about .005
If I first size my cases with a .340 bushing then with a .336 bushing I get .336 with about 80 per cent with .002 runout and the other 20 per cent with .003 runout.
Would a redding type S full length bushing die help or is there
anything else I can do to improve case runout.
My rifle is a sako trg 22.

 

[jpretle]

palo, I ran into the same problem using military brass. The more times the brass was reloaded the worse the runout got. I am now limiting the reloads to 3 times for military brass. I can get the 3x fired case to .001 runout, but only by 'over sizing', which leaves the headspace as much as .006 less than it comes out of the chamber.

 

[palo]

I forgot to mention Im using lapua brass.

 

[jpretle]

How much r/o is there as they come out of the gun? What ever there is, I think you will always have. I think the real cause of a lot of r/o is the varying thickness of brass. (thicker on one side of the case than the other, causing a bit of a banana shape.)

 

[palo]

How much r/o is there as they come out of the gun? What ever there is, I think you will always have. I think the real cause of a lot of r/o is the varying thickness of brass. (thicker on one side of the case than the other, causing a bit of a banana shape.)

About .001 .
I just wonder if sizing the neck and body at the same time in a redding type S full length die would help at all.

 

[Keith Glasscock]

I used to regularly "staighten" my 308 cases by FL sizing them. With Win brass, I sometimes got as much as .007" runout out of a Forster bushing bump die. Those cases went into the FL size pile to get "straight."

Funny thing is, I learned (when I aquired another 308) that FL sizing each time resulted in lower runout numbers throughout my ammunition. Best part is, I can load any case I find for either rifle and it works fine. I was initially worried about potential loss of accuracy, but I haven't seen anything that even makes me suspect that as being true.

The question is, how big is your chamber? My old factory Remington had an enormous chamber (before rebarrelling) and did not like "small brass." I learned quickly to double-shoulder the cases to keep the neck straight in the chamber. Looked funny, but it shot well.

 

[RonAKA]

A Lee Collet neck die is only $20. Some report excellent results. See this link:

http://www.jamescalhoon.com/collet.php

 

[amlevin]

I've been using the Lee Collet die for my .308 for some time now. Love the "no lube". Seat with a lee seater die and get runouts as low as .0002 and never higher than .003".

Lapua is best but Winchester, and WRA (Milsurp) also yield low runouts. The Winchester and WRA brass is neck turned just enough to even out the neck thickness.

I use Redding Body sizing die every 5 loading to keep the case easy to chamber.

Can't underestimate the Lee Dies. They're a lot better than their price might indicate.

 

[palo]

I will get a lee collet die to see if it helps.
Anyone know what size the outside of the necks are after sizing with this die.
Im using 308 lapua brass.

 

[Longtrain]

+1 "I've been using the Lee Collet die for my .308 for some time now. Love the "no lube". "

Started doing the same, my run is max at .001 with Lee Collet Dies, BUT, first I turn my necks to .0125, fire form them, then the Lee Collet Dies. Brass is Hornady Match, similar to Winchester in weight.

Tony

 

[260Ravage]

Please do not blast me for my techniques. I am an older man simply enjoying the sport of accuracy. I will not own a target gun if it doesn't hold 1/2MOA @300yds. Runout: I do not measure runout. After sizing and seating a new bullet I manually spin the new round in my case trimmer. I remove the pilot on the trimmer, insert the round into the trimmer, placing the tip of the bullet in the hole where the pilot belongs. I then turn the round,,concentrating with a keen eye on the shoulder area. It's very easy to see if a round has excessive run-out. I use the bad ones for sighters. I use lee collet dies and lapua brass whenever possible. I feel the biggest cause for run-out is that god-awful expander in the FL resizer. Freshly annealed brass comes out best in FL resizing, for it is flexible. I have a homemade, makeshift neck expander which I use to control neck tension. Sincerely FWIW

 

[Killshot]

Would a redding type S full length bushing die help or is there
anything else I can do to improve case runout.

I use the Full Length S Bushing dies. Though expensive, they will give you nil runout. After measuring around 600 cases the most runout I saw was .003. Nearly all (95%) have runout of .001 or zero.
I've stopped measuring.... ;D

 

[TonyR]

Palo. That amount of resizing is likely to be hardening the brass so you might also try annealing a few cases before you resize them to see if that improves your concentricity.

 

[clmayfield]

Try this:

Run your cases 3/4 of the way up the neck after firing, then after sizing, then at the ogive towards the tip after seating. If you neck size, then after you neck size and after you bump the shoulder.

You need to find out where the runout is coming from. I size in two steps, neck sizing first, then FL sizing. I got that from German Salazar and darn it if it doesn't work. Anyway, I had a runout problem at one point that I was trying to diagnose. I found a slight increase in runout with sizing... and then a huge increase with seating. The interesting thing about the seating was the distribution of the runout. I would produce a bunch of pretty flawless rounds - <.001", then I would make a bunch of >.002" with almost no in between.

There was something the matter with the seating die. I racked my brain. It was a Redding Competition Seater... a die many have had success with. I put in an order for another die. I thought about maybe milling the "plunger" portion that makes contact with the bullet a little more. I opened up the die to figure out what cuts I might need to make... and lo and behold a bunch of gunk had made its way into the "plunger."

The next time I sized and seated, I was getting much better results. About 65% showed less than .001" runout and only 5% showed runout >.002".

The point is not so much that you have gunk in your seater but to figure out where the runout is coming from so that you can diagnose the issue... is it your technique, your press, or your sizing or seating die? By checking each point in the process, you will know where you need to tighten up.

 

[dreever]

40% under .001
40% .0015
20% .0015-.002

Redding body die set to bump .002, then Redding Competition neck die with a .335 bushing for Lapua brass

For no turn brass I don't think I can ask for better than this.


Danny

 

[palo]

40% under .001
40% .0015
20% .0015-.002

Redding body die set to bump .002, then Redding Competition neck die with a .335 bushing for Lapua brass

For no turn brass I don't think I can ask for better than this.


Danny

Whats the outside diamater of your fired cases before you size them ?

 

[Martin52]

I use Lapua 308 brass, the fired necks are 0.340 o/d and I turn to 0.0140

I get nil or minimal run out on fired cases. Neck sizing with a Redding bushing die (0.335 bushing) gives me around 3-5 thou run out. The Redding FLS bushing die is better at ~2 thou. The Lee Collett is better still at ~1 thou, plus easier and quicker.

I do FLS every 4-5 firings and don't step down ie I don't use an intermediate bushing say 0.337, just go with the 0.335. Wouldn't go much more than this step down without using an intermediate size.

I've tried a few times and would like to think the results from the Redding would justify the higher price but the Lee comes through every time with the lowest run out. The Reddings are well made but the Lee just gets it right every time.

The Lee is also useful for checking base/ogive/lands measurements - just back off the Lee Collet die and the case mouth will lightly grip the bullet, seat a bullet long in the case, slide the case into the chamber and slowly close the bolt. The bullet should be gently pushed back by the lands to give you accurate measurement. I find this more reliable than both the Sinclair and the Stoney Point gages.

Martin

 

[dreever]

Palo,
In response to your question here's what I do:

Starting with new Lapua brass I open up the necks using a Sinclair expander mandrel die, then I neck size them back down using a Redding Competition neck die with a .335 bushing.
My loaded round neck diameter measures .33770 using a Mitutoyo Digimatic micrometer.
To answer your question above my fired round neck diameter measures .34125
I then use a Redding body die to maintain a shoulder bump of .002 I do this everytime to insure reliable and consistant chambering.
I then neck size the case using the aformentioned Redding Competition neck die.
I then use a Redding Competition seater to seat my bullets.
By lightly turning my necks I probably could improve the runout even more, but I don't find it necessary.
Using the Berger 185 grain HPBT Long Range bullet @ 2610 fps my GAP Hospitaller will maintain 3/8 MOA.

Danny

 

[palo]

Thanks for all the info guys.
I am getting a loan of a lee collet die from a mate at the weekend so I will see if that helps.