I have developed a load for my 300 RUM. The load consists of 180gr Barnes TSX, 92 grains of RL-25 and Fed 215 primers.
The chronographed velocity runs from 3289 to 3311. One hundred yd accuracy is sub 1 inch groups, however at 500 hundred meters (550 yds), I range between 6 and 9 inch groups. This is my first long range gun, and attempt at long range accuracy. Are these groups considered fair, good or very good?
I feel that these are acceptable for hunting, however shots at this distance while hunting, will not be from a bench rest.
5.75 is MOA for 550 yards your shooting just over moa at 550 yards. It depends on what your intending to shoot, if its White Tail deer then I would say you have a mod minute of deer rifle with the 6 inches, the nine would be moe minute of elk deer in respect to kill zone area but the 9 inch would also work for white tails.
Seems that the lower of the two velocities net you tighter groups as you expressed 6 inches and I assume the lower velocity was your first group?
You can no doubt improve by doing a few simple procedures, bed the rifle, pillar bed it, have the trigger tuned and examine the crown. Try some different powders too the new Retumbo seems to be the king of the hill for the new rums but thats just an observation without any facts. Try some VLD style bullets I can say without a doubt that using Berger's, JLK's or Richard Graves bullets will net you tighter groups instantly.
These things should net you a more consistant platform for launching your projectiles.
All in all I would be pleased with the 6 inch group and wonder about the 9 inch unless I was soly hunting mule deer or elk.
How many times have you produced 6 and 9 inch groups to get a standard. Sometimes one outting may produce this size groups while another may me totally different.
Consistancy is something that most always affects accuracy better than most other things.
Dave, thanks for the quick response. The rifle hase been bedded and floated, as well as a jewel trigger. I have stayed within the 6 to 9 inch range over three sessions. This morning I held a 6.75in 5 shot group at 550 yds. My hunch is, I need to keep practicing.
The opportunities for this fall are Bear, Elk and Mule deer in Western Colorado.
You might want to give the 180gr or 200gr Accubond a try. I think you will find they will give better Accuracy at longrange then a Barnes TSX. I myself would go with the 200gr it has a high bc and seems to shoot really well in most rifles.
I have good groups with the 180 accubond and 180 Speer BTSP using 99.5 gr. of Retumbo in a 26" tube. Don't know velocity, but very happy with groups from both. Shooting 3/4 MOA 4 shot groups out to 400 yards so far.
"I am a stone. I do not move. Very slowly, I put snow in my mouth and he won't see my breath. I take my time. . . I have only one bullet. I aim at his eye. Very gently, my finger presses on the trigger. I do not tremble. I have no fear"
I'd say based on the animals you intend to hunt that your 6 to 9 inch groups are well within the killing zone for all three animals.
Like others have said possibly try some other bullets like stepping up to 190 or 200 grain and see what happens.