Bushing Size Help

[CandianHunter]

Hello I have a question regarding bushing size for a redding FL bushing die I purchased for my 300wsm. I measured the neck of my adg brass with a loaded Berger 180 Elite hunter. .340" I'm also starting to use an expander mandrel for neck tension at .306". So am I right in thinking I want my neck size before using the expander Mandel to be around .304-.305 so that I'm working the nrass as little as possible ? What do you guys recommend for a bushing size ? I'm thinking 3.36 would give me 4 thou neck reduction and leave room to expand 2 thou with my expander mandrel ??

 

[Axl]

I think you have your decimal in the wrong place on your bushing size. If using a bushing I don't use a mandrel ever. I buy 3 or 4 bushings to try. A lot of guns shoot best with .004-.005 neck tension.

 

[PddPdd]

Agree, a .336 bushing ID would be about right or maybe a thousandth or two smaller in case you ever wanted to try .003-.004 "neck tension" in the future.

 

[CandianHunter]

Agree, a .336 bushing ID would be about right or maybe a thousandth or two smaller in case you ever wanted to try .003-.004 "neck tension" in the future.

Thanks for the reply ... what do you use for neck tension usually ? What's given you the best results

 

[Jesse09]

My own best practice, after neck turning new brass for uniformity, is to use the largest bushing that exerts just enough pressure to resist bullet movement when I press a dummy round against a hard surface. I've found that as bushing size decreases past that minimum, group size increases.

 

[Old Rooster]

My chamber is not custom so I don't turn necks and use .002 neck tension.300 win mag Lapua brass loaded round measures .337 and I use .335 bushing which gives me .002 neck tension.If your chamber is tight you will need to do as Jesse09 does.

 

[Mikecr]

I measured the neck of my adg brass with a loaded Berger 180 Elite hunter. 3.40"

I don't know what your neck clearance is but I would start with a bushing 2thou under loaded OD, as die makers recommend.
0.338"
If you have high neck clearance, the downsizing with this could end up a bit more than stamped on the bushing. Not a lot.
IMO, your mandrel should be around 1thou under cal.

This works necks minimally.

 

[Jesse09]

Old Rooster, I think we pretty much agree, overall; but, uniformity and consistency are the names of the reloading game. To that end, regardless of chamber tolerances, turning case necks gives that little bit more all-around even seating pressure. BTW, I think my bushing selection method yields the same .002" neck tension you report.

 

[PddPdd]

Thanks for the reply ... what do you use for neck tension usually ? What's given you the best results

.002 - .004 neck tension depending which groups are smallest.

 

[Rick Richard]

Start with .002 and go up or down accordingly. I usually go up or less neck tension in most cases.

 

[Varmint Hunter]

I normally start with a bushing that is .003" below loaded neck diameter. That allows for about .002" of interference after .001" spring back when the neck is removed from the bushing.

 

[WapitiBob]

I use a 30 cal decapper that's been turned down to .288 to straighten any necks that may have gotten dinged. That gives me the same neck od as fired rounds. Then I step down with two bushings, last is 5 under for .004 tension.

 

[Phil Rizzo]

like you all, I use bushing dies and Mandrels in every gun of my own.
Took a few hours today to work on a friend's custom 280 Rem.
Nosler brass, H4831 and BR2, 160 AB&BT. Nothing complicated or sophistcated.
Around 2850mv.

Both bullets averaged less than .5 moa groups after I found a good load, at 300yds.
Reading this after I got home and thawed out I have to ask myself, why I go through all that extra trouble ???
And his ES was no more than 15 on a 500yd max gun.
Regular ol sizing die, no mic adjustment and no bushing.
Answer for me is, I enjoy consistency.
And the dividends it pays at distancs