Problems with 'skewiff' bullet seating in 505 Gibbs

[John Weigel]

Massive bullet runout problem with 505 Gibbs reloading efforts.
I have a serious problem with my 505 Gibbs reloading process. I had a similar problem years ago with 458 Lott. Despite the greatest care I can provide, and even resorting to the ’seat a little, then spin cartridge, seat a little more, spin a bit more, etc, up to 20 steps to full seating, I cannot halt the tendency for the projectile to seat out of concentricity - to the point where you can actually see excessive bulging on one side of the neck. I’ve been spoiled with all of my other rifle calibres by use of the fantastic L.E. Wilson ‘floating bushing’ dies with use of Arbor press. It seems that the RCBS three-die set is the only game in town, and the seating die (unless I’m using it wrong) doesn’t properly retain neck position during seating. Not sure I can shoot any of my reloads - the projectile is going to hit the lands too far off centre. Have only used unfired brass - both in Bertram and Norma. Sized and unsized. I’ve tried resizing neck with the RCBS dedicated die, using it in incremental ’spinning’ alternative plunges too - which does actually seem to help a little - but not enough. Totally frustrated and disappointed. Factory loads would not only take the fun out of playing with my new toy, it would send me broke.
If anyone has experience-based suggestions, I’m all ears!

 

[piie]

Before seating, have you measured your runout? Perhaps your sizing causes the runout already?

Would suggest perhaps expanding necks with a dedicated mandrel to have less neck tension after you full length size, and perhaps dip the bullet base end in graphite powder before seating

also, make sure crimping is not also contributing to your woes. Backout seating die so no crimping is applied and measure runout again, you can always apply crimping incrementally later...

 

[Ares]

Well to start off with the basic, how do you size those 505 Gibbs cases ?
And how is the dies adjusted?
As the 3 die set from RCBS contains a FL die, without an expander.
A expander die.
And a seater die that also does a roll crimp.
It is not a usual 3 die set, as you'd get for most other cases

Also C4HD and Triebel offers die sets ready to go for it by the way, with a more conventional setup.

 

[243winxb]

Does the seating stem fit the bullet correctly. The nose of the bullet should not make contact.

Expander diameter- about .003" to .004" smaller then the bullet diameter.

Inside of the necks lubed.

Just basic stuff to check.

May be worth a call to RCBS?
But how are groups on target at 50 yards? Can you hit an elephant.

Had a chance to shoot one a few years back. A nice custom bolt action. Even with the portable benchrest that allows firing from a standing position, to much gun for me. No ty.

 

[MagnumManiac]

If you have the 3 die Safari set, I had the same problem as you.
I seated and crimped in separate operations to reduce runout. Best I could get was .001” with turning as I seated.
The 505 has a considerable throat, so the bullet tends to straighten itself.
I only used Woodleigh 600gr PP’s in mine @2350fps.

Cheers.

 

[INTJ]

I have had a similar issue with both the 45-70 and 450 NE. The shape of the seater stem is critical. I was asking Hornady how come they could load the bullets straight but I, using Hornady dies, their same 480 DGX, and Hornady brass couldn't get them to seat straight. The told me that they had a custom seater stem for that particular bullet.

 

[Kurz]

I'm looking at this from another angle:



Two things to look at:

1) Technically, the ball should be in contact with the area being measured not the stem.

2) Look at the area of the case neck where the bullet is seated. See the expanded area from the case mouth down then a smaller diameter area of case neck below that? Then look below that at the shoulder.

You need to expand the neck more then adjust your die to not impinge on the shoulder. Then check runout again.

 

[JTEX]

That shoulder also looks way to sharp, like you are slightly crushing the case....

Measure your bullets and make certain they are .505 not .510!

 

[John Weigel]

Thanks everyone. Human error on my part, mainly to do with not neck expanding correctly, and yes, damaging shoulder in process. Results are great now - no bulging neck, good concentricity (varies up to 5/1000's only) Thanks for the tips and suggestions - I feel dumb, but grateful! John

 

[Brians356]

If you have the 3 die Safari set, I had the same problem as you.
I seated and crimped in separate operations to reduce runout. Best I could get was .001” with turning as I seated.
The 505 has a considerable throat, so the bullet tends to straighten itself.
I only used Woodleigh 600gr PP’s in mine @2350fps.

Cheers.

Really? Only .001" runout is plenty good enough for an Africa magnum like the 505 Gibbs. I wouldn't think .003" is worrisome.
-

 

[Kurz]

Thanks everyone. Human error on my part, mainly to do with not neck expanding correctly, and yes, damaging shoulder in process. Results are great now - no bulging neck, good concentricity (varies up to 5/1000's only) Thanks for the tips and suggestions - I feel dumb, but grateful! John

It's not dumb at all, it's just learning. I guarantee you, we have all gone through similar experiences at one time or another.

I'm glad you got it to work out and that your runout is under control.

Enjoy!