Need loading info for 223 with magnum primers

[TopNurse]

I am using a Dillon 650 with a case feeder and at a LGS they suggested using >60 gr bullets in my DD 16" barrel with a 1-7 twist as they thought they would be more accurate. I have a chronograph if it helps.

After getting up to about 25 grains of Accurate 2230 I started noticing very slight primer cratering, but no signs of incipient head problems. I then backed down to 24 grains of 2230 and started using magnum primers as they are more robust in primer wall thickness.

My last load was 24.5 grains of Accurate 2230, CCI small rifle magnum primers, and Sierra 69 grain HPBT. I'm getting about 2850 fps and want to know if the 25 grains of Accurate 2230 is going to be a problem as I understand the magnum primers have a better hotter flame?

Also the primers must be slightly thicker than standard primers and when seated they sit higher in the case. There still about a .001-.002" below the case. Is there any way to safely increase the primer pocket depth?

How fast do you think I can get these Sierra bullets to go out of my 16" barrel?

[Mercmar]

The magnum primers are supposed to be the same size as "standard" primers. The magnum primers are probably unnecessary for what you're loading.

[fredj338]

Unless you are measuring w/ a micrometer, I doubt you are getting accurate 0.001" measurements. As Mer notes, the primers should be the same size. You do get a hotter flame w/ most mag rpimers. Thi can raise pressures, depending on what powder you use & how close to max you are. Standard rule fo thumb when loading near the top end; change anything & you should reduce charge wts at least 5% & work it back up.

[EMP 9mm]

Ok I have been useing mag primers ever since I started loading for the 223.now I load for a bolt gun and I have never had a problem when useing the mag primer.matter of fact most of my loads are at the high end for the choice of bullet/powder.I will add that I do a ladder test working up to the high end watching for pressure signs.

from what I have read the only thing thats the same is the OD and hight of the primers.the cup thickness and compound are different.

just keep working up to the charge in mind looking for signs while shooting.when you get some sort of a pressure sign then stop.I like to see/look for a good flat primer.the edge of the primer just starts to become square rather than round.if or when you see an ejector mark on the head you have gone to fare.even a hard bolt lift tells me I have pushed it too fare.

[fredj338]

Originally Posted by EMP 9mm

Ok I have been useing mag primers ever since I started loading for the 223.now I load for a bolt gun and I have never had a problem when useing the mag primer.matter of fact most of my loads are at the high end for the choice of bullet/powder.I will add that I do a ladder test working up to the high end watching for pressure signs.

from what I have read the only thing thats the same is the OD and hight of the primers.the cup thickness and compound are different.

just keep working up to the charge in mind looking for signs while shooting.when you get some sort of a pressure sign then stop.I like to see/look for a good flat primer.the edge of the primer just starts to become square rather than round.if or when you see an ejector mark on the head you have gone to fare.even a hard bolt lift tells me I have pushed it too fare.

It's not that you can't use mag primers, .but you just shouldn't plug them into a near max or ma load w/o working back up. You are going about it the right way. Stay off the top end & swapping primers isn't an issue either.

[TopNurse]

Originally Posted by Mercmar

The magnum primers are supposed to be the same size as "standard" primers. The magnum primers are probably unnecessary for what you're loading.

The only reason I started using magnum primers is that I was told that the part that gets hit by the firing pin is a bit thicker. Figured it might help with the small amount of cratering I was getting. No more cratering, but still about 1/2 grain off the maximum load.

I have seen bolt actions that get hard to open, but what do you see in a AR-15 when pressures are rising too high?

When testing my loads I raise them up about 1/2 grain at a time and load up 10 rounds. Five are slow fire while using a chronograph and the other 5 rounds are fast fire.

[EMP 9mm]

cannsay for I do not own an AR rifel.but your on the right track with your reloading.maybe some one who owns an AR will say to what you need to look for.

[fredj338]

Originally Posted by TopNurse

The only reason I started using magnum primers is that I was told that the part that gets hit by the firing pin is a bit thicker. Figured it might help with the small amount of cratering I was getting. No more cratering, but still about 1/2 grain off the maximum load.

I have seen bolt actions that get hard to open, but what do you see in a AR-15 when pressures are rising too high?

When testing my loads I raise them up about 1/2 grain at a time and load up 10 rounds. Five are slow fire while using a chronograph and the other 5 rounds are fast fire.

A bit harder on any semiauto. You do NOT feel the bolt lift, but the case heas still show pressure signs. Flattened primers is always one, then look for extractor dents in the rim area. A higher pressure round will need more force to extract & leave a mark. Also look for breech face "wipe" or marks on the case head. If you see smears across the lettering, your pressures are high. If you have a good micrometer & can use it, you can measure case head expansion. Compare that to factory fired cases. If you get more than factory, your pressures are higher. Steel cased factory doesn't count, cases have to be of the same mat'l.

[TopNurse]

Originally Posted by fredj338

A bit harder on any semiauto. You do NOT feel the bolt lift, but the case heas still show pressure signs. Flattened primers is always one, then look for extractor dents in the rim area. A higher pressure round will need more force to extract & leave a mark. Also look for breech face "wipe" or marks on the case head. If you see smears across the lettering, your pressures are high. If you have a good micrometer & can use it, you can measure case head expansion. Compare that to factory fired cases. If you get more than factory, your pressures are higher. Steel cased factory doesn't count, cases have to be of the same mat'l.

Sorry for taking so long to get back here, but I started a new job and I've been busy. Thanks for all the helpful info. I use a dial caliper now and know how to use a micrometer...just got to go out and buy one now.

Would you recommend using a digital or vernier scale on the micrometer?

[fredj338]

Originally Posted by TopNurse

Sorry for taking so long to get back here, but I started a new job and I've been busy. Thanks for all the helpful info. I use a dial caliper now and know how to use a micrometer...just got to go out and buy one now.

Would you recommend using a digital or vernier scale on the micrometer?

For measuirng OAL, dial calipers are fine. There isn't much use for the precision of a micrometer in reloading IMO. Checking case head expansion is about the only thing I would need such precision. My only complaint about dig is like anything elec, yo uget what yo pay for. Cheap dig don;t last long. I burned up a cheap FA dig caliper & never went back, just go steel dial & it always works.