Issue with Missouri cast bullets in 9mm

[dirkdiggler]

I have been reloading with Missouri bullets in .357, .45 and 10mm without any issues but I have stockpiled a bunch of 9mm in 115 gr that will not pass the plunk test in any firearms that I own.

They're coated 9mm 115 gr at .356 diameter. I've tried the following with dummy loads:
Crimping between .372 and .377...no luck
Plunk test with case only....perfect fit
Seating bullets deeper and deeper and deeper...between 1.135 and 1.035. Went that low just to see if they would chamber...I know that's too short.

I typically use Blue Bullets coated 115 gr without any issues. With the Missouri cast 9mm they'll fit in my glocks and sigs with loose chambers but stick a tiny amount. None of my CZ's will chamber the Missourie loads except the P-10c.

Suggestions?

[SI VIS PACEM PARRABELLUM]

From the look of it there may not be enough ogive in the missouri bullet from the look of it. The Blue bullets 115 gr. looks to have a better ogive which will function better in the CZ chamber.
I have a Lee 9mm mould which looks just like the Missouri bullet and bullets from that mould are unuseable in my CZ's.

[IDescribe]

I'd strongly recommend against crimping narrower than .377 with any bullet, and for .356 lead I'd go to .378.

Anyway... Here's a bit of trouble-shooting you can do to make sure this is an issue with the ogive contacting the rifling and forcing you to go that short VS the bullet sticking in the leade a bit, which is no big deal. 

Resize a case and insert it until it headspaces, and open up your calipers super wide, and take a measurement from the MUZZLE of the barrel to the case head.  Write that down.   Then resize a case and seat one of those bullets WAY too long, crimp to .379, plunk it in the barrel, and take that same measurement.

IF that bullet is hitting the rifling and not sticking in the leade, the difference between the second and the first is how much shorter you have to seat to get the case mouth to headspace properly on the chamber step.

Calculate that OAL - - it's the OAL of the long cartridge minus the difference between the two muzzle to case head measurements.   Right off the bat, I'll tell that if that calculated OAL is longer than the 1.035 you said wouldn't chamber, your problem is that the bullet is sticking in the leade.

Otherwise, you know your max OAL, and I'd try loading them to that OAL minus an extra .010 for cushion, and as long as they functioned, I wouldn't care what the OAL was.

Take those measurements, though, and let us know what they are.

[Wobbly]

A simple fact:  Not all bullets for sale can be used for reloading in all pistols.

I buy and use MBC bullets all the time, but as with any bullet maker, when you use them in the CZ pistol, you MUST be very selective. If you'd have asked us before the purchase we could have advised you as to exactly which ones.

These bullets probably work great in any number of 9mm pistols, just not your CZ. The cartoon below tries to explain the issue...



 

[IDescribe]

I just looked at the bullets.  They don't look too squat to my eye.  I would definitely make attempts to troubleshoot and make sure I'd identified the problem before giving up on them.

[Wobbly]

Since he never gave a model number so I'm having trouble guessing which one.

I suppose it could be the MBC "Small Ball" which is very deceptive. That one always gives trouble.

[IDescribe]

Small Ball is 124gr.  This guy's are 115.

[jameslovesjammie]

I just looked at the bullets.  They don't look too squat to my eye. 

I don't know.  If you look at the sizing marks on the traditional lubricated bullets instead of the coated bullets, the nose looks fairly short to me.  2nd from the right is a good example.