A quote--" Note that with H110 you must use magmum primers such as CCI 350 or Federal 155."
I often wonder where these kind of statements originate. It says you must use magnum primers, so then I wonder what will happen if you just use standard primers instead. Will they just go phizz, or pop, or what will happen?
Well, in this case I can tell you what will happen. The exact same thing will happen with a magnum primer as will happen with a standard primer in the case.
As I have mentioned on here before, over the years I have owned and shot five 44 magnum revolvers and two Marlin rifles. I have shot silhouette, where one Ruger was being fired 1,000 rounds a summer, all with my own bullet pouring and loading. I have used H110 more than any other powder and I always used standard primers.
Then I got Winchester 296 and they gave the same maximum loading as I had used for H110, 24 grains, with a 240 grain bullet. I think they said to use a magnum primer, so I got some. Then I chronographed some loadings. I found no difference, whatsoever, in any way, between whether I had used a magnum, or a standard primer. And that applies to any powder I have used.
Some will say you "need" a magnum primer in cold weather shooting. I just looked at my notes, and these tests were made during a January at an outdoor range!
It seems to be common knowledge that H110 is the same powder as W296. When I got W296 I noted they said to load exactly as shown, don't reduce the load. Again, it didn't say what would happen if I reduced the load, but it hinted at all sorts of dire going ons, if one reduced the load. I had a bit of a laugh at that, because I had already used H110 for a lot of years, in the 44 mag, as well as the 357, plus as reduced loads in centre fire rifles with cast bullets. I had many times reduced the loading, to find a good shooting, light load in the revolvers. I notice in my notes that in the 44 mag, 15 grains will leave some unburned powder, but even 15.5 seemed to burn OK. Some of my most accurate loadings were in the area of 17.5 grains.