Please help - bullet runout

[Anders Bruun]

Hello Mark

If I use a standard die, it moves the brass to much, for my manny times of reloading. Often you will have the expanderbutton making runout on the way out. Alså it gives me too much neck-tension.

In the beginning I just could not understand, why my 6.5 was perfect and I was struggeling with my 308, using the same system

Thanks AB

 

[Pdvdh]

One thing I have done a couple times in the past to reduce the amount of working the neck down from fired cases in factory chambers that were cut overly large is to neck down a larger caliber case that was a close match to my cartridge.
Three examples that I remember: I currently use 338 Win Mag brass to form 7mm Rem Mag cases. I anneal the necks after sizing down, outside neck turn, and have reduced the slop between the finished necks and the large chambers by about 0.0015". I've used 340 Weatherby brass to make 300 Win Mag brass but only reduced neck clearance by about 0.0005". And I make 280 AI brass from Lapua 30-06 brass, but this is in order to take advantage of the higher quality Lapua cases.

But in my experience, you'll only gain ~ 0.001" reduction in neck clearance by necking down a larger caliber case to a smaller caliber neck diameter. And I don't know if there are any 33, 35, 375, or 40 caliber cases that could be converted to 308 Win by stepping the necks down because that's a round I've never owned or reloaded for.

0.009" is on the high side for neck clearance for sure, even in a factory chamber.

Oh - sometimes just changing brands of brass will help reduce neck clearance by 0.001". Best way to figure that one out is to just take your dial calipers into the gun shop and ask if you can measure the neck diameters on some different brands of factory cartridges. The loaded bullets will all be the same diameter, so the brand of cases with the largest outside diameter will be the brand of brass you'd like to purchase. lightbulb

Good luck.

One last tidbit. You haven't said how the rifle shoots. Zero runout is the goal, but if it drives tacks with 0.002" runout, then I'd be happy driving tacks no matter the runout.

 

[Anders Bruun]

Thanks for your input - and yes that could be a good idea, but i just fireformed and preb. 400 Norma cases, and invested in the Redding comp die set, so I really hope to get this combo to work

Still I´m under .002 so far - so let´s see if they don´t shoot well annyway.

I checked my chamber, and it is spot on SAAMI spec.

Just unlucky for me, if Norma has the thinnest necks on the marked in 308

Thanks AB

 

[Pdvdh]

Thanks for your input - and yes that could be a good idea, but i just fireformed and preb. 400 Norma cases, and invested in the Redding comp die set, so I really hope to get this combo to work

Thanks AB

Yikes! You've got some money invested in Norma brass. Well I sure hope they shoot lights out for ya...

 

[MontanaRifleman]

Hello Mark

If I use a standard die, it moves the brass to much, for my manny times of reloading. Often you will have the expanderbutton making runout on the way out. Alså it gives me too much neck-tension.

In the beginning I just could not understand, why my 6.5 was perfect and I was struggeling with my 308, using the same system

Thanks AB

Howdy Anders,

I understand now that you were talking about the clearance between your neck and neck chamber.

I'll try not to beat this horse too much more, but I would still (and do) turn my necks if using a bushing to avoid irregularities in the inside of the neck. But if you're getting less than .002 runout that might work well for you.

So bottomline, it sounds like to me the Redding bushing die is doing it's job and runout is probably/possibly caused by the unturned necks?

Cheers and good shooting - let us know how well it shoots,

Mark

 

[Anders Bruun]

Thanks Mark

Yes I will get back to you, when I get a chance to go to a range.

Regards

AB

 

[grinnergetter]

Holy crap....I read threads like this and realize I dont know beans about reloading. Geeezzz some of that needs serious study. Thanks