Zero 185 JHP Diameter too large?

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Shooters,

Last week I received my back ordered 2K Zero 185gr JHP bullets labeled part #187 and started loading some this evening.

I noticed right away that the bullets don't hand seat nearly as far into the case (barely at all) as the Hornady XTP and HAP bullets I've been loading. And running through the bullet seating and crimp dies there is a clear increase in resistance vs the hornady bullets.

I finally had the thought to measure these new Zeros with my calipers. I got the same results measuring across and along the bearing surface.  Out of 20, they are 0.454 but a couple slightly smaller 0.4535.  I pulled the bullets from two Roze-loaded 185gr JHP cartridges from 2019 and those both measure 0.453. I measured 20 Hornady 185gr XTP and 20 Hornady HAP bullets and all are 0.452.  I measured a few Zero 185gr SWCs and those were 0.454 like these Zero JHPs.

I've fired 500 or so of these 2019 Roze-loaded JHPs through my Pardini GT45 that my sample of 2 measured 0.453 and they have shot well.  It's been shooting well with the Hornadys measuring 0.452.

SAAMI says 0.452-0.003 for jacketed.  The Hornadys all meet this spec.  Why don't the Zeros? Zero part #187 is supposed to be .451 bullet. 

I'd love to go shoot these in the morning like I had planned.  But because the bullets don't fit in the case nearly as well after expansion and the increased feedback in the ram handle when seating the bullets I don't think this is just a matter of the bearing surface being irregular and playing with the calipers.  And because each Hornady sampled measured 0.452 and the new Zeros measure 0.0015-0.002 larger in diameter, even if my calipers weren't accurate the Zeros are still repeating a relative increase of about 0.002" diameter over the Hornadys.

Has anyone measured the Zeros with these diameters?  Are your new Zeros larger than expected? Or is measuring the bearing surface here going down the wrong rabbit hole?

I was very excited to receive the bullets but now I'm apprehensive - not sure if they are safe for my pistol that I've invested so much time in.

Any input appreciated.  Thanks

No signs of pressure but I will repeat what Wobbley said - Federal primers WILL flatten in 45 ACP very prematurely. I experienced this myself and it was driving me crazy when I was developing a hardball recipe; changing to literally any other primer I had (CCI/Remington/Winchester) completely resolved the issue. I would not worry about it.

OK thank you for the feedback!  Regarding Federal primers (which make up 90% of my primer stock) is it that they cannot handle as much pressure, or rather that they just show pressure earlier?

SingleActionAndrew wrote:OK thank you for the feedback!  Regarding Federal primers (which make up 90% of my primer stock) is it that they cannot handle as much pressure, or rather that they just show pressure earlier?

I really don't know. I have shot thousands of them with success, but as previously noted they like to flatten and will give you a scare on occassion.

Federal can handle pressures as that is more a function of the bolt than anything else.

They are, however, misleading in pressure signs and because if the softer cups, more prone to slam fires in autoloading rifles.

Wobbley wrote:Federal can handle pressures as that is more a function of the bolt than anything else.

They are, however, misleading in pressure signs and because if the softer cups, more prone to slam fires in autoloading rifles.

Thanks Wobbley! I don't have any autoloading Rifles, so to be clear no similar concern with autoloading Pistols (1911)? Thanks!

No.  Mostly because of the design of the firing pin usprings in autoloading pistols.  Most self loading rifles do not have firing pin springs, and that is one of the issues.

Just received new stock 185 JHP from Magnus.  Measured 10 #J-187 with micrometer.  Largest .4529, smallest .4527, all the rest .4528.  Haven't shot any.  Not concerned.