New to the forums here!

I was looking at the Hornady 9th Edition Manual. I wanted to load up 180gr FMJ bullets to something similar to what my factory ammo has been, roughly 1150fps listed. Looking at the manual that would take about 11.5gr of powder. Ended up screwing up measuring my powder load and found that the powder measure was throwing 11.8gr (this is why I double check with two scales periodically), but that's still well below the 12gr maximum listed in the manual. So all is well, have a few test loads leading up to that to make sure that I don't blow up my Glock 20, as well as the reassurance that 10mm reload data is always a bit conservative a COL that's a tad over the 1.260" to avoid overpressure from that.

However, after doing a little reading, I ran into a problem. All my other load data shows that Hornady's data seems to be very... generous. Their 12gr listed maximum is a full grain above what I see anyone else at for 180gr bullets, and they all peak at around the high 1100's in terms of FPS. However, all of the other load data is either for plated bullets, or for hollow points. So I am not sure if Hornady is somehow wrong with regards to this bullet/ powder combo (I am doubtful, since Accurate #7 would probably be one of the more popular powders for a cartridge like this), or if the other load data just doesn't apply to FMJ bullets [seems weird that out of Lymans, Lee, and Accurate's own load data, none of them apply to 180gr FMJ].

Is anyone who is actually using Accurate #7 with 180gr FMJ-Flat Nose bullets able to shed light on whether or not the listed data in the manual is just wrong or dangerous?

Load is as follows:

• Hornady 180gr FMJ-FN
• 11.8gr of Accurate #7
• 1.262 COL
• Winchester LP Primer

Hornady's data can be on the warmer side of what's published, and I probably would have started a bit lower than 11.8 (I realize you intended to start at 11.5).

I've loaded a 180 jacketed FN up to 11.2, and settled there because: Case expansion was getting towards my stop point; Frankly, there are better powders for pushing 180s.

All that said, I'd shoot your 11.8gr without hesitation, out of my G20.4.

ps: You could always load a few at 11.2 & 11.5 and see how those feel / look / etc before shooting the 11.8s.

.02

Oh I intend to. Was probably going to go 10.5, 11, and 11.5. I'm suspecting I'll probably hit that 1150 mark before that 11.5 point the book says though, and that's fine with me. Honestly not too terribly interested in reaching a maximum velocity. Reason for using Accurate #7 was that I may experiment with using it on 9mm for my CZ Scorpion. Accurate 5 is too fast for 10mm probably, while 9 is too slow for the 9mm. Wanted to see if I could get good results on both using the same powder and just stock up on that.

Being they are FMJs and not JHP they should be shorter inside the casing so that would help.
Accurate Arms data shows the 180 gr Speer JHP using No.7 11.4 grains @ 1232 fps 36,600 PSI
Accurate Arms data shows the 190 gr Speer FMJ using No.7 11.2 grains @ 1198 fps 36,000 PSI

If you're running in the factory barrel you may want to check case expansion or for smiled brass.  I didn't see what brand of brass you were using!

Ah! Fresh Starline brass. I figured if I was testing a new load to use good fresh brass. After that is used I'll probably back the load off and reuse it (assuming it's still in good shape), as well as some Armscor, Sellier and Bellot, and Sig brass. The Sig stuff I was impressed with performance wise, and I wanted something with a bit less umpf, probably between the S&B and the Sig. From what I could find, it was actually loaded above what manuals recommended, but even that didn't get me any deformed brass or smileys, so I was impressed. Considering it's the cheapest I can buy locally (S&B is cheaper still, but has to be ordered online so.... Shipping costs for ammo), I was pretty happy. Brass looks good too.

Just an FYI, your starline brass will probably be the strongest on the second or third loading, assuming you don't bulge it.  Brass work hardens and starline is on the soft side to try to give longer life before a split.

My Hornady manual shows a starting load of 9.3 grains.  How did you starting loads and work up load look?

Huh, that I didn't actually know. Up until now all of my reloads were 9mm, so I'm relatively new to this.

and I was starting at 10.5. I know it's a grain above book starting load and not starting at the minimum is a bit of a faux pas, but I was a bit short on powder and bullets to experiment with. My primary concern is if the Hornady data is somehow out of date or just wrong for the powder.

Actually Speer #12 also shows there 180 grain Gold Dot and TMJ over a max of 12.0 grains of #7 @ 1180 fps as tested from the S&W1006.

A timely discussion for my situation.  Loaded up some 180 XTP with 11.4 of AA #7 in new Starline brass as per the Hornady book to use for hunting with my Kimber Stainless II.  After looking through Accurate's load recommendation, I promptly ordered a bullet puller to start over.  That said, I did load some of these same bullets with 9.4 of 800X which is in the Hornady book but is above the max for the powder manufacturer and fired them through my G29 with aftermarket barrel.  They are hot but no bulges or leaky primers.

Good news! No issues with the 11.8gr of Accurate 7. No bulging, primers seemed fine, no leaks or cracks. Only real issue was that I had a ton of light primer strikes. 4 out of 60 fired is not something I like to see; the primers looked like they weren't hit hard enough, with the divet being quite shallow. They'd fire after careful refeeding though... Possible they're seated too deep, or is my pistol to blame?

Obviously recoil was snappy, but not terrible.

Did you go to the extra power firing pin spring on you gun?  If yes try the factory original again to see if things improve.

Shadow

I put the heavier 6# firing pin spring in my G20SF assuming it would provide a stronger strike.  In your post recommending going back to the stock spring, how might that help prevent light strikes?  I could see going back to stock from a lighter spring but not heavier.

The spring is what retracts the striker, as you release the striker the spring is compressed to hit the primer, then retracted by the spring.  Also if there is something not put together right that can increase drag that could hamper striker movement for a full strike to the primer.  I some occasions, if the cartridge is holding slightly out of full battery you can see a light strike to the primer.  That happened as a piece of alloy stuck to the end of the chamber of my G-30 when using cast bullets.  A quick cleaning removed that debris and the gun functioned properly!