Federal 205 primers

[Gringoloco]

[grayfox]

The 205's, and 205M's, would be fine for a bolt gun like howa. But I would not use them in an AR, the cups are relatively soft/thin and a slam fire is what you might get... not a happy day.

I used the 205Match in my howa and they were fine, even better than the 450's for the loads I chrono'ed.

[RetroJunkie98]

[StoneHendge]

Federal 205Ms are fine in an AR. I've put over 10,000 through the wringer without a slam fire. 205's reportedly have the same primer cup thickness. I often see posts on here that they can cause slamfires but have never come across anyone who has actually had one. Scroll down the link for "the chart". https://www.accurateshooter.com/tech...sure-analysis/

[Gringoloco]

I live in central Arizona so my idea of cold is 45F lol. I got a few different powders to try and work up loads with in 1lb quantities like H335, CFE223, BL-C2, and 2520. Assume that those combos should work ok to start with at least then work some ladders up on until/if other primers become available again?

[StoneHendge]

The difference between 205s and the 205Ms is reportedly that Federal uses more experienced employees to make the M's, resulting in better consistency. The only difference between the M's and the MAR's (AR Match) is the thickness of the primer cup. So from a load perspective, all 3 are interchangeable. I've shifted between the 205Ms and 205MARs without a measureable change. So if things become "normal" again and you like your load, 205MARs will give you the same performance. If you shift to CCI's, the 450s will ignite faster and the 400s will ignite slower.

With that said, whatever you do with CFE 223 today will change completely come late April. I'm in the north valley and the load I used to use in Colorado that would run 2580 on afternoons like today would run 2660 on August mornings here at 9 am - with major pressure signs. Just keep it in the back of your head since it seems like your just starting out with reloading and try to think every now and then about how everything is performing at different temps. Most of the powders you listed are above average in sensitivity (I would consider CFE to be extremely sensitive once it gets above 80) with 2520 probably being the most average.