Recently I received some 300 RUM brass that I split with another member. It is Federal branded. I had a couple of days to test some loads previously developed with Rem brass. I took my 300 to Colorado with me (by the way, just got back last night, will post kill pics when I get them via email)---and found some interesting but not surprising results.

I've had a very good load for the 200 Accubond and 89.0 Re25. This is a max load for this rifle using Rem. brass. In fact, the bolt is minimally stiff, but not difficult. (What I call true max). When I tried the exact same load with Fed brass, the group was considerably more impressive than the half inch I was already getting but trajectory to 300 was diminished. The Federal brass had ZERO pressure signs and no stiff bolt lift at all. 2 bullets went in the same hole at 200 yards, the 3rd was 1/4" inch away. (shooting with solid rest). The Federal brass load had less velocity as it was about 3" low at 300, where the Rem brass load was Zero at 300. I think I'll be adding some powder with the new brass just to see what happens, even though the 200 yard 3 shot group was quite impressive.

Just something to play with. I still have some mixed emotions about the AB bullet but it sure is accurate. It's hard to change something when it shoots that good. I haven't played quite enough with the TSX bullet in that rifle, but that is coming.

Doc,
Are you sure you are actually lower in velocity with the Fed. cases or is the point of impact different because of barrel time?
Also what you can do is fill each case with water and see what you get for a weight/volume for each. I am guessing that one has a larger envelope.

Smed

Just weigh a Fed case and a Rem case. You'll probably find the Rem case is heavier. Thus smaller interior space. The Fed, being roomier has more expansion room. If you have a Chrony, you'll probably find the fed, at that charge, gives you less velocity. If you have a Chrony, wonder what your accuracy would be if you backed the rem cases speed down to match the fed velocity?
The other post confused me. How can you have greater "barrel time" without having lower velocity??

Well, on the "barrel time" issue, Smedley didn't write "greater barrel time" he wrote "different...."

I realize I can do the water test. Just didn't have time. I'd say based on past Rem. brass experience, the Fed is lighter, thus holds more powder on avg. I tested both at 50 to 300 yards in 50 yard increments without taking a chrony to CO, the Fed is slower as it has a bit more rainbow trajectory. It hit lower at all shots and dropped more than the other load. I'm not complaining at all, just wondering what will happen when I boost the powder in the Fed brass and continue to adj. seating depth if need be.

In 30-06 Rem brass is heavier than WW brass. I got lower velocity for the same load in the WW brass. I won't swap max load components right off the bat, though.

I worked up to the 89.0 grains in the Fed brass as well.

As a general rule, you'll find that Remington brass will have less internal volume in almost all calibers than Federal or WW brass. I'm sure there is some case where this isn't true, but it has been for me.

I had a time tested load for the 35 Whelen AI that my stepfather gave me. He had worked the load up using Winchester 06 brass necked up and fireformed. I tried the Remington brass and was getting minor flattening of the primer. Sold the brass and am going back to Winchester which is my preference anyways.

Just so that somebody has said it, I wouldn't purposely load up to where I was getting any sort of snugness in the bolt lift, I'd stay where you know you are under prssure even if it costs 50fps.

Red

Considering the same midpoint trajectory you'd have to slow down about 275 fps to see a 3" drop difference at 300 yds. (at least according to a combination of "best guess" and my ballistic table. In 30-06 I see about 75-90fps diff between rem and win (I consider these the high and low of normal case capacity barring military stuff). I think federal falls somewhere in the middle. It will be interesting if you chrono the two loads and see the diff. If I was to bet I can't believe there would be 100 fps between the two loads (which is probably good for 1-1.5 grain diff in load??) Bottom line is I bet you could back off the rem load and get near the same accuracy but thats if neck tension etc. is a match between the brass.
Also...from what I can read it was a one time 3 shot group that you are talking about....this would be far from being a good proof load compared to many loads with your rem brass that you might have shot during load developement.