300 RUM with annealed Nosler Brass...


Well-Known Member
Feb 2, 2005
My normal 300 RUM load of lately has been 93 grains of Retumbo, 0.015" into the
lands using Nosler brass. At long range it's been a shooter for a factory barrel but at
100 yards... you feel like throwing up.
Well, I annealed 50 Nosler cases that had been previously shot twice in the same rifle. All 210 gr. Berger bullets had previously been sorted by bearing surface.

I decided to see the difference in point of impact from shooting off of a front rest from the bench and shooting from the bench off my bi-pod. After I had seen the difference and was satisfied with the results, I decided to stop shooting paper and shoot other things like coke cans at 300 yards and different things at different distances. It all went very good and I am highly recommending annealing your brass.


In the pic above, my first three shots from a cold bore, and off the bench using a
front rest. The center of the 3 shots went 1.245" high and 0.447" left. The group
is 0.692 moa. This is definitely not bad at 100 yards compared to how it had
shot in the past.

Now it's time to put on my Harris bi-pod on it and shoot another 3 shots.
The scope turrets were left untouched.


Well, well... This I had never seen with either of my two 300 RUMS at 100 yards,
If I had shot all 6 rounds without altering the rests, out of 6 shots 5 shots would have been a big nice one hole. I'm attributing all this goodness to the annealing. What do
you think?
It was a good practice section, the rifle will shoot from prone position right on also
using the bi-pod.

On my last group, the center of the tree shots was 0.090" high and 0.121 right. I Think I'll leave it like that! :cool:
0.289 moa isn't the greatest but is good enough for me...

I almost forgot, the ES of the chronographed sample was in the high single digits and low double digits...
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I started annealing this past summer, and also found my accuracy improve, along with better ES.
I load retumbo with the 210 grain berger to and I use nosler brass can you tell me how you annealed your brass? I think I'll try some . Do you remeber your average muzzle velocity? When I was breaking in my custom barrel It didn't like the high side of retumbo maybe now that it's broken in I'll give it another try and load some @ 93 grains . I would be proud to have shot that last group even with a custom barrel!

I agree. I started annealing last fall. When you can feel that some bullets go in easier when seating,,, it is time to start annealing.

Good shooting my friend!

Thanks for reading and comments guys.

trueblue, it really works, I agree.

bigbuck, 93 gr. = 3023 ft/sec corrected to the muzzle, it's kind of max according to
the reloading books, but I have run it above 3100 with no problems, I
settled for 3023 ft/sec because of accuracy. The annealing I do it
just like the videos posted above, just don't let them get red-hot.
Every time you anneal, your brass will elongate a bit more after firing (more than it would otherwise), so make sure and measure it and know your chamber length so that your cases don't elongate too much, 'cause then you'll have to trim again and trimming means neck turning again, and...so on... Some BR guys are/were apparently annealing every time, but man, what a pain and the brass that elongates is coming from somewhere, so it would seem that the case is thinning somewhere, perhaps more than it should.

Case Gauges & Headspace Tools - Sinclair Chamber Length Gage

The difference between SAAMI trim lengths and your actual chamber length can be substantial, so it's nice to know the difference. You many not have to trim as much if your chamber is long, like mine. If I recall from Sinclair's book, they would measure chamber length and then trim .021 shorter than that--apparently going through the loading books, that seemed to be some kind of average amount trimmed back from chamber lengths. My chamber is 2.872, if I recall correctly, and I trim back to 2.838 initially, and generally don't have to retrim during the life of the case.

I tend to get necks starting to see the start of cracks/splits after 5-6 firings, (probably partly due to a factory chamber that allows the neck to expand a great deal and then get smashed back down a great deal by the die to the proper size really working that neck hard...) so usually every 3 or 4 firings, I'll anneal again. Actually had on older case split yesterday while practicing--knew that could potentially happen, just got too lazy to anneal that batch as that was the last firing I was planning for those pieces of brass. Trying to find a compromise between neck life and doing alot of work by annealing every time.

Not sure you guys were talking about annealing every time, but thought I'd share my experience in case you were.
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Definitely an interesting observation. I'll keep my eyes on those things. Thanks for posting.
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