Couple question's about 9mm C.O.A.L measurments .......

[chopps]

I know it matters somewhat to what you gun likes and cycles but, how much does 10 to 20 thousands make on the round pressure wise ?

My lee dies normally are about 10 thousands either way plus or minus but my old dillon dies were 10 to 20 thousands either way and still cycled fine on 124 gr rn bullets.

Just curious if I am being to anal trying to get them as close as possible and really only reason I am asking is I am loading some 147gr jhp's and there kinda ranging from 1.100 to 1.120 and I just hate I can't get them closer.

Plus this is the 1st time I am loading a heavy projectile with HP38 3.6 grains ( per lyman and handloads.com recipies plus a old one that I used on 147 truncated that worked good) and trying to be at 1.115 overall to start with.

Now 124 rn I can keep them within about 10 thousands and never have any issues for just practice ammo and thats normally all I load.

This is the 1st time I am loading personal protection ammo to see what and how good it works in my skill set.

Thanks for any help and data.

 

[Springfield 1911]

As long as you are longer than the published data you should be good to go. You are also in the midrange of the load, pressure should not be an issue. Just put a good crimp on em and try em out.

 

[chopps]

As long as you are longer than the published data you should be good to go. You are also in the midrange of the load, pressure should not be an issue. Just put a good crimp on em and try em out.

Yeah I try to stay mid range to account for the variable of 10 to 20 thousands.
Last thing I want to do is be on thr fringe and have issues. Its practice ammo for the most part and occasionally some jhp's.

 

[Glockadopoulos]

As said above, just go longer than Lyman data. I recently made up several dummy rounds with 147 gr bullets cast from a lyman mold, varied the OAL from 1.050 to 1.140 I believe. Went with a pretty mild taper crimp on all of them. I then did a torture test slingshotting the rounds into the chamber from a mag, up to 25 times and then measured for a change in OAL. I simply couldn't get the rounds to set back at all, and that includes testing in a range of brass headstamps.

Just like feeling of high primers, I've come up with a very quick and simple test for relative OAL uniformity. I take a flat piece of glass and set it on top of 50 rounds on a flat surface after I've loaded them. If there's one with a significantly wrong OAL, you'll easily see it.

 

[noylj]

Bullet set-back is usually concerned with changes greater than 0.1"--very noticeable change.
Always do a push test.
COL (Cartridge Overall Length) varies due to differences in bullet profiles and meplat variations due to swaging process variations and bullets coming from different swage dies, and any "give" in the press. None of those are significant to the reloader.
This is what you are concerned about:

 

[gth813x]

I usually do the min. Oal but that's jut me and I have never had issues except for in a 1911

 

[woodstock]

I usually go max length or just under as long as it cycles well.