OAL

[willthesaint]

Hi guys

I was at the comp the other day & a discussion started after 2 rounds jammed in my chamber/barrel about the OAL of my bullets.

Can anyone shed some light onhow to most accurately measure the OAL of a 9mm bullet for my CZ please. Is there any devices that I cam purchase?

regards

Will

[GrumpyOne]

Search SP01 and OAL.

[Jonathan Taliani]

Are you asking how to measure the OAL of a round? If so, you can just use a caliper.

If you are asking how to determine the maximum length your barrel can take with a given bullet, check out this link: Determining Chamber OAL

[myproverb]

Definitely use a caliper; I prefer dial over electronic, but they'll both do the job. Also, use a flat nose/truncated cone bullet or a hollow point; this will give you an ammo length of approx. 1.09" to 1.10"--it solved my problem when I was having the same issue.

[gmg]

Load a dummy round, remove your barrel, stick your dummy round in the your barrel chamber firmly and try to turn it. If it won't turn, seat the bullet and little deeper in your case and repeat. If it's too long it won't turn. I had to load mine short, around 1.110 - 1.115 to get them to turn freely. I have since lengthened my chamber to be able to load them longer. I am shooting 147gr Bayou Bullets.

[willthesaint]

Thanks gmg. I also tried smoking the bullet to see where the lands line is then backed it of 30 thou. The bullet seems very short.

[SteelShooten]

The transition from the chamber to the full depth rifling is abrupt in CZs. As a result they tend not to behave well with full shouldered bullets unless they are loaded short.

I went through the same exercise with my SP-01 and decided to have a machinist provide a more gentle leade in the barrel. I gave him a slightly long cartridge to use as a gauge. He put the barrel in a lathe and made a series of incremental cuts, paring away the top surfaces of the rifling just ahead of the chamber, checking each time with the 'gauge'; until the cartridge chambered properly and slipped out easily.