Safe OAL range for JHP ?

[randomBytes]

While setting up my machine this afternoon, I used an existing FMJ
round to find a starting point for the seating die (9mm fwiw).
When seating a HP (Xtreme 124gr I only have a few dozen of these so this is just mucking about), I got a shorter OAL due to the different profile. 1.100" which didn't seem unreasonable considering the load manuals cite lengths like 1.050" (though none for that specific bullet).

Now as it turns out my glock didn't want to feed that round - the nose reliably jammed on the feedramp. It did chamber fine though.

I reduced the length in a few steps, and by 1.075" it was feeding better.
I haven't taken it all the way down to 1.050" yet, I figured it worth asking some questions first.

While not using the exact same bullet as the loading manual, for a given weight, the suggested OAL is still a useful guide?

Most importantly, provided I end up somewhere between that at the max allowed for the cartridge, am I in safe territory with respect to pressures?

[Bill Steele]

Well, the OAL isn't a suggested length. It is the minimum length the ballistician tested with that max load for that specific bullet listed. What that means is if you load shorter with the specific bullet listed or you substitute bullet profiles or types, you are doing your own load development, albeit at a reasonably safe starting point.

My recommendation would be to try some longer as well and see how they feed.
I usually load my 9's in the 1.140 range. Perfect feed, better accuracy, generally speaking.

[GeoffLinder]

Yep, a slightly longer OAL will tend to feed better in 9's IME. 1.130-1.140 range is always a good range for JHP or FMJ IMHO.

You will not want to use the same powder charge for both though, you would want to work it up for each bullet type.

[randomBytes]

Thanks for the tips, these xtreme HP's are a pretty fat profile btw.
The WWB 115gr FMJs that my gun has consumed by the thousands, are 1.160 and the 147gr JHPs 1.115 and have a much narrower tip than the xtreme's.

At 1.140" the xtreme HP still jams when it is the last round, but feeds ok (as before) when there are others. That's with a g17 mag in a g19.
With g17 (same mag) it feeds better even as last round, even when riding the slide, but occasionally still runs into the feed ramp.
g19 mag in g19 maybe feeds a bit better.

I'm not super worried about these bullets as I've only about 50 of them.
I have 2k JHP from precision delta coming some time this year I hope
and these look more like the winchester JHPs (which feed fine).

With luck I've attached a pic of the round hung up on the feed ram,
in the g17 this happens about 1/8 times.

[randomBytes]

With OAL of 1.160" it fed much more reliably.

[Bill Steele]

With OAL of 1.160" it fed much more reliably.

Good news.

As Geoff pointed out, when you go from your shorter OAL, to the long one, you may need to add a small amount of additional powder to get the same velocity.

Another thing that might help in the future when you run into feed issues on the ramp is to polish it. It is amazing how little polishing it takes with a bullet shaped felt pad on a dremel and some Mother's or Simichrome to make it like a mirror.

[Memnok]

With straight walled pistol reloading, overall length is the thing I seem to get hung up on the most. Bullet profile changes so much that I question the reliability of the data that is published. Just looking at the profile of Zero, Berrys, and Montana Gold, three popular manufacturers, there is a big difference in the shape of the bullet. I'm getting a chrono for just this reason; peace of mind that my seating depth isn't ramping up the pressure.

[randomBytes]

BTW when I first started testing OAL of 1.160, I noted that I was getting bullet setback after the repeated chambering, so added more crimp...
I got to the pont that the crimp was ridiculous, and the bullet was lose!
Basically I'd reused that one bullet too many times.
I backed off the crimp quite a bit, used a new bullet and case and confirmed that the OAL held after chambering.

[J-cat]

What you should have realized instead is that crimp does not prevent bullet setback.

[Prophet]

1.150" OAL works for Berry's 124grain RN.