OAL flat vs round nose

[mrdaputer]

Hi by mistake I bought 124 grain flat nose instead of 124 grain round nose. I am using titegroup and the chart says OAL 1.150 load 3.6 to max 4.1. I am guessing the load would be about the same for both bullets because they both are 124 grain. The flat nose is .050 shorter than the round nose. My question is would the OAL change?

[RedHawk357]

Thinking the correct answer is to redo the work ups due to component change. Next would see if you can find data for specific bullet. Probably pretty close I would imagine but you never know. The lack of finding any of that I would consider what is the difference in seating depth for your new bullet vs the old one. If it sits more shallow then the original bullet, thus more air capacity in the cartridge, it should produce less pressure with all other things being equal like bearing surface. And plunking it in your pistol barrel and comparing to your magazine requirements for overall cartridge length will get you going for your firearm. I find making ten test rounds much more time efficient than playing wacko a mole with 40 or 90 cartridges. Good luck.

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[g.willikers]

"About the same" might be close enough for some things, but not for reloading.
Bullet weight is only part of the similarities between different bullet designs.
Overall length of the bullets themselves can matter more.
Not to be confused with loaded cartridges.
Follow Redhawk's advice.

[mrdaputer]

I load low to begin with so that is not a issue to me. I never have seen a reason to load hot. just trying to figure out the OAL

[Jim Watson]

I would do the arithmetic and start out loading FP to the same seating depth as RN.
Case Length + Bullet Length - Overall Length = Seating Depth.

You have done it the easy way, the bullet is .050" shorter so seat it to .050" shorter OAL for the same seating depth, therefore the same powder space.

If that did not give a workable load, adjust as required to plunk and feed.

[TailGator]

I would do the arithmetic and start out loading FP to the same seating depth as RN.

Yup. Worked for me with .380.

[egd]

Taking the .050" off will get you close, but this ain't horseshoes or hand grenades. The seating stem measures off the ogive of the bullet and that may be different between the two bullets. You need to determine where the seating stem hits on both bullets and calculate so that the same amount remains below the stem.

[mrdaputer]

Thanks Jim for the info. That's what I was thinking but wanted to make sure and figured someone here has done both and it's better to be safe than sorry.

[44 AMP]

I am going to ASSUME you are talking about loading the 9mm Luger. I did not see the actual caliber/cartridge mentioned anywhere.... (hint)

IF you ARE talking about the 9mm Luger (aka 9mm Parabellum, 9x19, etc) then the max overall length with bullet is 1.169"

As long as you are below that, the rounds should function in your gun.

My question is would the OAL change?

(if you don't change anything on your seating die??)

yes, probably

Will it matter? Probably not.

The seating stem of your die, generally does not contact the very tip of the bullet.

bullet is .050" shorter so seat it to .050" shorter OAL for the same seating depth, therefore the same powder space.

This may, or may not work, depending on the specific bullets used. What matters here, to maintain the same seating depth of the bullet, it the distance between where the seating stem touches the bullet and the base of the bullet.

And this you will have to check with your components. IT is entirely possible that your die will seat both to the same bullet depth in the case, with the adjustments AS IS, and the 0.050" longer bullet nose is in the hollow of the seating stem, affecting NOTHING.

IF that is the case, moving the stem to "compensate" for the shorter bullet does NOT compensate anything it just seats the shorter bullet that much deeper.

It is also possible that because of the different nose profiles, and where the stem contacts them, that the seating depth of the two bullets will be slightly different. YOU have to check what you have, and see which of these is the case.

[lamarw]

You might want to email the bullet manufacturer and ask for their recommended OAL. You can then use it as a starting point if you want to attempt to improve upon it.

I have requested this info a couple of times in the past and received quick responses. I know one time it was from Berry's.

[T. O'Heir]

Been loading .45 ACP with cast 230 RN's and FP's for eons using the same OAL. Like 44 AMP says, assuming 9mm, use the 1.169" OAL. Save you a lot of mucking around.
"...this ain't horseshoes or hand grenades..." Or nuclear weapons. The OAL is not measured to any ogive. It's measured from the pointy end to the flat end. If the pointy end happens to be flat, so be it.

[Nathan]

If we are talking handgun, redo the plunk test and see how it comes out. My guess is the shoulder will be at the same point, creating a shorter oal. That means the volume of the tip is inside the case reducing volume. I would do ocw work up with 3 loads under current and 1 above current. In those 5, you should be able to reestablish your load.....probably .1 gr increments for 9mm.


Understand what your books say for max and mins charge for as similar bullet and primer as possible. Nice to have 2-3 sources.


Or you could just try it...

[egd]

Maybe I wasn't clear in my response. The oal is not measured off the ogive, but that is where the seating stem contacts the bullet, not on the tip. (unless you have a flat seating stem) If the ogive is a different shape for the two bullets you may not be able to use the same seating die setting. But if the bullets are from the same mfgr and have the same profile, except for the tip being "cut off" so to speak, you may be able to use the same seating die setting. Although the oal will still be different.

[Jim Watson]

That's why seating dies are adjustable. Turn the screw.