Zero 158 gr SWC question

Hi,

I see that the Zeros are popular here.  I was going to order some but was curious why the Zero's are sized .357 and Remington, Hornady, Speer size their HBWC and 158 gr SWC at .358.  
http://www.rozedist.com/mm5/merchant.mvc?Screen=PROD&Store_Code=RZD&Product_Code=R110-A&Category_Code=ZSB-38S

38Shttp://www.midwayusa.com/product/1601162951/remington-bullets-38-caliber-358-diameter-158-grain-lead-semi-wadcutter

The .358 diameter HBWCs shoot great in my guns.  If my barrel is slugged at .357 would the Zeros be an issue with leading and such?  If so, do you folks have any thoughts on Remington, Hornady, Speer or others for accuracy and such.

Thanks,
Dave

I think that's a nominal size. The ones I measured were closer to .359. They shoot great and I have no leading issues in my Model 14.

Wonderful, thank you Ralph.  I will place my order!!
I appreciate your help,
Dave