Bullet seating ?

[Wanted]

I have loaded Hornady 55gr FMJBT and Hornady 55grSPP, both with cannalure. I loaded them the same length. The cannalure on the FMJBT is right at the case mouth. The Spirepoint is a little above it. Is this because of the diff. in a boat tail as apposed to the flat point?

[G-ManBart]

I have loaded Hornady 55gr FMJBT and Hornady 55grSPP, both with cannalure. I loaded them the same length. The cannalure on the FMJBT is right at the case mouth. The Spirepoint is a little above it. Is this because of the diff. in a boat tail as apposed to the flat point?

Sorta, kinda, but not exactly...it's unusual to find two bullets with the exact same ogive shape even if they're the same basic design. I expect the manufacturer figures people will simply adjust so that the cannelure is right at the case mouth, and probably bases reloading data on that different OAL. The actual reason why they make them that way could be for any number of factors...they may have tested and found more consistent results using the OAL when seated so the cannelure is even with the case mouth, or they chose it for case volume/pressure reasons...etc. R,

[Wanted]

I've been loading them at 2.250 which works perfectly in my guns. So would it be alright to leave them like this? I really don't want to change my OAL.

[ah141nj]

I've been loading them at 2.250 which works perfectly in my guns. So would it be alright to leave them like this? I really don't want to change my OAL.

You seat for whatever works best in your gun. Just keep it below mag length or you will be single feeding.

[High Lord Gomer]

The load data I have seen suggests that 2.250 is the correct OAL. I have found that if I go much over 2.260 then the bullets hang in some mags. To get the cannelure where I can still see a little bit of it above the case mouth (I use MG 55gr FMJ-BT) I have had to trim a little below the recommended 1.750. I trim at 1.745.

[Wanted]

Thanks for the help everyone.

[Graham Smith]

OK, now I'm really confused. Until I started loading .223, I had done 9mm, .40, and .38SP. Of the three, the .38SP was the only bullet with a cannelure and that was simple, just set the OAL so that the cannelure aligned with the case mouth.

With .223, however, I'm finding that doing the same thing can give me an OAL that is quite a bit off the SAMMI spec. This makes me unsure of what to do. Should I ignore the OAL and align the cannelure with the case mouth or ignore the cannelure and set the OAL to spec?

[High Lord Gomer]

What is the length of your trimmed cases?

What OAL are you getting by aligning the cannelure with the case mouth?

What kind of bullets are you using?

[Graham Smith]

Well, this is embarrassing but a good lesson. I'm just getting started with .223 so have a lot to learn about rifles and I was having a lot of problems with case sizing to start with. Anyway, after getting that sorted, I'm just started setting up my seating and crimping dies and the batteries in the calipers died. OK. Got replacements and could now finally get the dies all set up and I find myself looking at a OAL of 2.275 with the cannelure and the case mouth aligned. WTF? Checked, rechecked, and checked again. WTF?

So, last night I sat down and started checking things again. I hadn't checked the zero on the calipers.

Now that I've got accurate measurements, I can seat them (55gr MG) right at 2.260 with the case mouth bisecting the cannelure. That's not as short as some people say they prefer, but at least it's in spec. I'll have to see what I can get if I seat them down so that the cannelure is just showing.

[High Lord Gomer]

I seat the MG 55gr so that just the very top of the cannelure is barely showing above the case mouth. With the cases trimmed to 1.745 that results in an OAL of 2.250. Be careful with 2.260 as that might hang in some magazines.

[Graham Smith]

I seat the MG 55gr so that just the very top of the cannelure is barely showing above the case mouth. With the cases trimmed to 1.745 that results in an OAL of 2.250. Be careful with 2.260 as that might hang in some magazines.

Thanks. This has been one of life's little lessons of the kind that need to go on a plaque in big letters on the wall behind my workbench, "Check the f*ing zero, moron!!!"

[jaredr]

The load data I have seen suggests that 2.250 is the correct OAL. I have found that if I go much over 2.260 then the bullets hang in some mags. To get the cannelure where I can still see a little bit of it above the case mouth (I use MG 55gr FMJ-BT) I have had to trim a little below the recommended 1.750. I trim at 1.745.

interesting, i noticed the same thing when i started using MG 55gr ball (had previously been using hornady but tried out MG when hornady was unavailable). MG miked out a few thousands longer, and I actually had to adjust my seating die out a bit to keep the bullet seated to about halfway on the cannelure. At that seating depth, bullets were right under limit for my PMAGS, so screwed down the dillon trim die a half turn to keep overall length on the safe side. bullets shot well and were very affordable, so no complaints about tweaking the loading setup to accommodate their slightly longer projectile length.

-jaredr