I wouldn't EVER make a statement that they are the same as, about as hot or cold as any other primer. There simply is NO comparison. Use data for the exact components you are loading. That said, if you MUST use them, start with a load that develops a low enough pressure to give you enough headroom for a dramatic increase in pressure. Looking at some of the Rio data I've seen, they can vary quite a bit, depending on the load. I would treat them as the hottest primer listed for your components and go from there. Certainly stay away from the top pressure loads if swapping primers.
I bought 20 thousand and started using them. Loaded them like Fed 209A's with the 1 oz loads they worked fine until you started to get around 1250 fps loads (~9k psi with FED 209a) and I started getting primer piercing about 2 per 100 and increasing with velocity. This with 3 different powders e3,clays,promo and 2 shotguns. With 1 1/8oz loads this started with 1145fps loads (~9K psi with Fed 209a) and again got worse if I tried to go up any. Later testing of the primer cups on various 209 primers showed that these had the softest material of any I tested. I used a spring loaded center punch with the tip rounded and measured how much the cup material compressed against a soft steel plate. 3 of 10 of the RIO cups actually allowed complete punch through during testing. I sold those that I had remaining and moved on. Just my 2 cents worth.
If you load them in any once-fired hull (especially steel base) on a P-W press you'll want to pre-prime them on something else. Then remove the P-W de-primer punch before you load them the first time or 2 or it's like stuffing a cat through a keyhole to get them in. After that the primer tunnel is stretched enough to let the P-W prime them. You can't go back to any other primer in those hulls.
Alliant actually has a few formulas for Rio primers in their data base. I remember that they're there but can't remember where they are except that they are listed in loads you would shoot for trap. OK, they are in data for 1 oz. loads in Federal GM hulls and 1 1/8 oz. loads in Winchester AA hulls.
Rio primers are engineered to be used with lots of slow-burning powder (35 grains in a 1 1/8 oz 2 3/4 DE target load) in hulls with lots of internal capacity. They quickly build pressure (lots of it) lighting fast burning powders in tight tapered-wall hulls.
Some guns will punch the primer cups. The savings on the primers isn't worth the expense of replacing the burned firing pins.
318bill; I and 2 friends have used over 30000 with 1 miss fire and no other problems at all.We all load light and get better powder burns with them. You can go back to rems wins if you deprime and resize hull with mec supersizer. We only shoot heavy loads with slow burning powder.I have not used any other primers for the last 3 yrs.
My problem isn't with Rio primers. It's with people that make irresponsible statements without data to support it. Yes I shoot and have shot trap, skeet, and other clay target games since the late 50's. My ATA number is of no consequence. Would that somehow convey some magical amount of knowledge or expertise that a non-ATA member would have? I've also reloaded shotshells and metallic ammo since then as well. When someone says primer x is the same as primer Y, they need to have some data to support it. You made the statement that they are about as hot as the Winchester W209. What data did you use to support that? Have you actually compared the data at the link on the page you linked to with data from other sources and data with other primers, especially the Winchesters you referred to? I'd like to see your comparisons and conclusions. The link to the pdf with the Rio supplied data is above.
If you read what Rio has posted on their site about the performance of their primers with certain types of powders, etc, then take a look at what characteristics the powders they recommend have, it doesn't fit many of the common powders we use for reloading in this country (USA). Large straight tube hulls and single based powders are what they were designed for.
I don't like Rio hulls or ammo. That's not a secret. It has performed dismally for me and personal observances of numerous basewad migrations makes me avoid them, even from the factory. The factory reps lack of concern and response about the issue was less than impressing. I will use Rio primers under some circumstances, but have found that they can drive pressures up in many loads. That's the reason I recommend caution when substituting them for another primer in the loading data. Common sense is not always that common.