280 Ross reloading journey.

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Well, after years of looking, I finally landed a set of NOS RCBS 280 Ross dies last fall. Since then I’ve dove right off the deep end into reloading for the fabled old Ross cartridge.

Before I get into it, a quick disclaimer: loading for this old cartridge is basically wildcatting at this point in time. What I do likely will not work in your rifle, nor am I implying any of this is safe! Do your own homework and play extra safe!

Starting out in this, I had a set of dies, some leads on the internet for possible start loads and info on brass to use and 50 Woodleigh 175gr .287 bullets that were gifted by a friend. What I found out very quickly is do not believe what you read in rifle mags or on the internet. It could kill or maim you or your rifle.

I had read that 300 win mag or 7mm rem mag brass could be used. I had some of both on hand, once fired. I did some quick checks with calipers against case dimensions listed in The Ross Rifle Story, and 7mm cases will not work. The 300 cases are long enough, but are belted and the base of the case is slightly undersized. I had lots of it and decided to roll the dice.

Published loads in a handloader magazine from years ago listed 7mm rem mag start loads of H4831 as being a safe start point for 280 Ross. In proper purpose built 280 cases this may be the case, but in fire formed 300 win mag cases using a 7mm start load will result in dangerous overpressure signs. I had flat primers immediately. I shot three of these rounds just to make sure it was t just on the line and by the third round it was pretty obvious. That one not only flattened the primer but gas actually perforated the cup and escaped. That’s pretty close to a catastrophe. I pulled the pin at that point and went back to the drawing board.

What I found was using the 300 brass you wind up in a reduced case volume which puts you closer to 280 AI volumes. I decided to try a load closer to this, and gave 55gr of H4831 SC under a 154gr Hornady Interlock 284 a shot. This load did ok, no pressure signs and a 2.5” group in my M-10. Next I tried the 175 Woodleigh at 52gr H4831SC. This produced no pressure signs and a 1” group. I shot this load last fall for hunting in that rifle.

These cartridges were loaded at 3.575” OAL, which according to TRRS is .075” too long. The M-10 feeds them fine, but the SDS will not, which I did not find out until this summer.

Fast forward to this spring. I acquired a near new condition SDS (1907-E). I tried the .287 Woodleigh load in this rifle, and it did not impress. 3-4” group (this rifle is scoped). So I went back to the Hornady 154gr .284 bullets and it loved them. Nearly a 1moa group on a guess load of 55gr 4831. Next to try was the .284” Hornady Interlock 175gr over a 52gr load of 4831. This was less stellar at 2.5”, but the load even sounds ‘light’. These loads had to have a COAL of 3.5”, and resulted in a big jump of 0.080” to the lands. But, decent accuracy and no pressure signs.

The next range outing I tried some Hawk 160gr .287 bullets loaned to me by another member. This was over a 54.5gr 4831 load at 3.5” OAL. Not a winner at about a 6” group. I also tried a Speer 160gr .284 flat based bullet over the same load and length, but it was even worse at about 8”. I decided to abandon these and not chase any further in this rifle.

That catches us up to today. I have loaded ladder tests in both .284 Hornady bullets, and will go up in .5gr increments until I see pressure signs. Hopefully this will produce some favourable results!

Another caveat, this SDS seems to be sensitive and picky about primers. I tried Ginex LR primers in it but wound up at about a 60% FTF rate. Seems the cups are a bit hard or the main spring in that rifle is getting soft. Fiocchi primers cured it completely.

I have two other 280s in good shootable condition and plan on playing with them down the road. Seeing what I’ve learned so far, I expect each of them to settle on a vastly different load from the rest.

Pics in next post!
 
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