9mm How deep to seat?

[ZachJ]

I have been using some campro 124gr hollow points, which have a max OAL of 1.100" to pass plunk test, and spin freely in my CZ SP01 Shadow. The charge weight I've been using is 4.1gr of TG.

I just got some campro 124gr round nose. From plunk test and spinning freely, the max OAL is 1.160". I double checked in my 85B and Jericho 941 RPL as I thought my barrel might have been out of spec, but it passes in them too.

I also checked the projectile dimensions, and it's the same length as the hollow points, and same diameter, .355"

I'm asking what OAL I should load at, I've heard load as long as I can, which I would make 1.140", but do I lose any velocity by loading this long as opposed to say 1.100"?

Edited March 22, 2016 by ZachJ

[Hi-Power Jack]

You'll probably lose a little velocity, but the RN configuration makes

it acceptable to load longer - which offers some advantages.

Try it at 1.12", 1.13" and 1.14" and check the accuracy and feeding.

Don't forget to chrono the winner to maintain PF.

[acpie360]

I have been using some campro 124gr hollow points, which have a max OAL of 1.100" to pass plunk test, and spin freely in my CZ SP01 Shadow. The charge weight I've been using is 4.1gr of TG.

I just got some campro 124gr round nose. From plunk test and spinning freely, the max OAL is 1.160". I double checked in my 85B and Jericho 941 RPL as I thought my barrel might have been out of spec, but it passes in them too.

I also checked the projectile dimensions, and it's the same length as the hollow points, and same diameter, .355"

I'm asking what OAL I should load at, I've heard load as long as I can, which I would make 1.140", but do I lose any velocity by loading this long as opposed to say 1.100"?

Since Seating Depth = Bullet Length + Case Length - COL, I would start with the known 124GR HP recipe and find out what the seating depth is. If you keep 4.1gr TG, use the same seating depth, then the internal pressure should remain the same with the new 124GR RN bullet. In other words, I would start with

New COL = New Bullet Length + Case Length - Old Seating Depth

Load 10 rounds without power and primer, do the plunk test, do the magazine fit test. If power charge and seating depth remain the same, I doubt you'll notice any difference in muzzle velocity.

[9x45]

I've loaded 124s over 4.3grs Tite Group down to 1.060" and up to 1.165", just depends on the bullet shape.

[MemphisMechanic]

I tried titegroup (under a 124JHP) at 1.010, 1.120, and soft on up to 1.060 in my G34 back when I started loading.

It was roughly a 20fps variation, if that.

As long as you're nowhere near a compressed load (and that's unlikely with TG) I wouldn't stress about it personally.

[IDescribe]

Yeah, evaluate your seating depth and that should give you a better indication of what sort of velocity drop you'll get. You'll probably see a difference of around 0.1gr for every .02 difference in seating depth to maintain same velocity.