Resizing .357 after seating

[ColinR]

I use a Redding Competition seater for .357 cartridges - I am told this is the most accurate die to achieve inline bullet seating. However when seating .358" lead bullets they slightly swell the case at the base of the bullet and also reveals that they are not always totally straight, as the swell will be more pronounced in one direction. Probably not a problem, but I have put a batch back through a carbide sizer after the bullet has been seated. This seems to straighten the bullet alignment and removes the slight swell in the case. They shoot fine and MV is the same as cartridges not resized a second time. This process seems OK in theory and practise, but am I missing something?

[dromia]

If it isn't improving things other than visually why add another step.

It is not something I would do as it is also sizing down the bullet and undersized bullets can lead to leading and loss of accuracy.

[ColinR]

I have not had a chance to determine any definitive improvement in accuracy, but surely if the bullet is entering the rifling even slightly out of alignment that can have an influence? I take the point you make regarding leading.

[dromia]

Removing the bulge doesn't necessarily mean that the bullet is centred.

The bulge could actually mean that the cases are off centre.

Best to use a "M" die style expander die for square bullet seating, tight toleranced bullet seaters designed for jacketed bullets rarely work well with cast.

Lead bullets are relatively soft and what might be happening is that the bullet is getting squeezed off centre to centre it. So you might just be deforming the bullet.

Depending on the distances you are shooting it might not make much difference on the target at 25 yrds.

The only way you will know what is happening is to measure a bullet before seating, pull and measure one after seating and finally pull and measure one and check its concentricity after seating and resizing.

I'd also check the barrel regularly for leading as it will build up and not be necessarily obvious at first with deformed/undersized/hard bullets.

[ColinR]

I think I will just leave well alone as the current set up shoots OK to 100yards. What is an 'M' die?

[dromia]

Parallel sided, stepped, case neck expander die used in loading cast bullets originally made by Lyman.

[Alpha1]

I can not see a picture Adam.

LYMAN
Rifle (M) Die
Improves accuracy of cast and jacketed bullet reloads. Doesn't stretch cases as does standard expander button. Extends case life. Many reloaders consider Lyman's Neck Expanding (M) Die a valuable tool for improving the accuracy of their reloads. The die's expander plug has two steps.

rifleDies_mdie.jpg (10.57 KiB) Viewed 1044 times

[dromia]

Didn't post an image, that is why you can't see it.

[Alpha1]

It says image in your posts my mistake.

[dromia]

That is where the signature image should be but photobucket seem to have lost it.