I know it's a sign of high pressure, but should you always back a load up when primers are flattened? The two cartridges I'm seeing them in are 44 mag and 223 rem. I haven't loaded either to max published loads. The 44 load I've been using is 23.1 grains h110, WLP primer under a 240gr nosler. The 223 load I saw them with was 26.0 win748, cci mag primer (all I've got), and a 50 gr amax.

Flattened primers alone are not always a sign of over pressure. Many commercial loads have primers that reaaly get flat and have no other sign of overly high pressure. So just by itself a flat primer may not have great significance. roger

CCI are pretty hard, so if you get flattened primers w/ sticky bolt lift or exctraction, then you are definitely too hot & should back down till that goes away. Softer primers, like Federal, will show some flattening sooner.

My experience loading for .223 using Vit N133 24.8 grains under either a 52gn Amax or a 40 gn Nosler Ballistic tip cci primers, has produced flat primers , but smooth bolt lifts & ejects, pretty much the same with Hodgdens Benchmark too, no worries!

quote:

Originally posted by bartsche:
Flattened primers alone are not always a sign of over pressure. Many commercial loads have primers that reaaly get flat and have no other sign of overly high pressure. So just by itself a flat primer may not have great significance. roger

While I agree here.....a flattened primer to me is always a reason to be very watchful.....it may be the first warning sign of things to come.....don't ignore it but also don't go batshit over it either.

If, with a large case you're working up a full grain at a time you might want to start working up 1/2 grain at a time.....If they get extremely flat I will quit regardless of the absence of other signs.

quote:

Originally posted by bartsche:
Flattened primers alone are not always a sign of over pressure. Many commercial loads have primers that reaaly get flat and have no other sign of overly high pressure. So just by itself a flat primer may not have great significance. roger

Roger is correct. It's only when flattened primers go along with hard bolt lift and/or expanding primer pockets that you should get concerned........ abd back off several grains of powder.

Thanks everyone. I haven't seen any other signs, no stiff bolt lifts or anything. I noticed on some factory 44s I shot that the primers were pretty flat. Was surprised to see them in the 223s, thought perhaps the mag primers was causing over pressure, but no signs other than the primers.

Flattened primers alone aren't necessarily a reason for alarm, but if I see flat primers along with other common pressure signs (hard bolt lift, velocity spikes from that load, primer cratering, etc.) I would usually back off on that powder charge.