Reloading 165gr fmj 40cal

[Mattroth54]

I'm getting back into reloading. A few years back, I acquired a Lee turret and a bunch of components. I never really had a nice supply of brass, so other than dabbling with a few loads here and there, it's just kind of sat. I'll soon have a nice supply of brass, and would like to get this up and running. Question, I have about 1000 165gr fmj bullets, and a pound or so of Unique. Alliant publishes data for a 165gr GDHP, using 7.2gr of Unique. Since these are both jacketed bullets, am I good backing off by 10% or so on the powder, keeping the minimum OAL the same as published? There's not much out there published using the components I have on hand. Thanks!

 

[oldpink]

I see that your data came directly from Alliant's published data for the GDHP/TMJ.
My Lyman 38th edition lists 5.0 grains of Unique as the starting charge for that bullet and 6.0 as the max, so it appears that Lyman was being rather conservative with their data.
The Speer 14th edition lists their min/max as 6.2/7.2 with that bullet, so reducing your charge to 6.5 grains with that particular bullet sounds perfectly safe.
I've loaded the 165 grain GDHP and the TMJ in 10mm Auto for quite some time, along with the 155 grain GDHP and TMJ, and all four bullets are excellent.
In fact, if you're wanting a load that almost perfectly matches the ballistics of the superb GDHP (assuming that you're intending to either hunt or have as your carry load the GDHP), you're better off using the TMJ, both because it's a tad cheaper and because it's much easier to get.
You can keep your precious stockpile of GDHP for when you need them for more serious business than paper-punching that way.
Be sure to use a taper crimp, or (better yet) use the Lee Factory Crimp die with your loads for feeding reliability and to prevent slippage.

 

[Mattroth54]

Just to be clear, the core of my question is ensuring the GDHP and a jacketed bullet of same weight are interchangeable when looking at published loads. I know OAL could be different, hence backing off on the charge. Am I way off?

 

[oldpink]

Just to be clear, the core of my question is ensuring the GDHP and a jacketed bullet of same weight are interchangeable when looking at published loads. I know OAL could be different, hence backing off on the charge. Am I way off?

If switching to a different bullet altogether, you might get yourself a little extra leeway by using the published starting load data (6.2 grains), although you're probably still safe with 6.5 grains.

 

[Mattroth54]

I loaded up a couple at 6.3gr (how the Lee disc spit it out without doing much math stacking doubles). They shot real nice. The spent cartridges look identical to factory once-shot brass, showing no sign of overpressure. I'm feeling real good loading a batch with this recipe. I'm just looking for consistent target/plinking rounds. These seem perfect. I really appreciate the help.

 

[oldpink]

Good to hear that you're dipping your toe in the water gradually to ensure no mistakes.
You'll love it getting into reloading at a more dedicated level.
I've been at it for over thirty years now...where the hell did all that time go?

 

[Leo]

165gr is a great shooting projectile weight in the .40 S&W. Glad you found success so fast.

 

[Leo]

For your question. Length of the bullet tip actually has very little to do with the powder charge. Bullet weight (mass) and the length of the major diameter (friction) are the largest factors in the safety end of things. Of course, in a semi automatic cartridge OAL has effect on how the gun feeds. Your bullet choice is pretty well documented, so you avoided a lot of experimentation. Maintain records, if in the future you want to load bullets that you cannot find exact published data for, you can measure them against known bullets and get a comfortable base line for a start load.

 

[rg1]

In my Glock 23 with Unique powder, CCI SP primers, and Win cases I get 956 fps with 5.7 grains, 6.0--1008 fps, 6.3--1030 fps, 6.6--1070 fps. I like Unique for 165 FMJ's in the 40 but my favorite powder is Win SF, Winchester Super Field. Seems to be a softer recoiling powder? My oal with the 165 FMJ-FP is 1.125"