Berger’s twist rate stability calculator says you’re fine
https://bergerbullets.com/twist-rate-calculator/
https://bergerbullets.com/twist-rate-calculator/
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But what is your air density? I'm at sea level and during the summer months my 1/9 twist is fine with an air density of +150 ft but when the temperature drops below 20 F I start to see air density readings of -2000 ft and when it gets down to below 0 or below I see air density readings of -6000 ft. At a 1000 yards my groups were opening up considerably when it's cold. I was baffled why the same load was suddenly giving me fits until I ran the numbers with the Berger twist rate calculator and an elevation of -2000 ft it shows a 230 as marginally stable 1.42. At 1/8 twist gives you a 1.79. So I went to a lighter 215 Berger which is slightly more stable bullet for winter months until this barrel is wore out and I can get a 1/8 spun up for next year.I live at about 400 feet above sea level and a 1-9 twist stabilizes the 230 berger
No was just wondering. Everyone I talked to, or read have said 1/9 for 230's. I'm close to 6000 ft of elevation. Had a 1/8 on my ASR. But want a 1/9. Just didn't know why you were having issues. Good to know. Merry Xmas.But what is your air density? I'm at sea level and during the summer months my 1/9 twist is fine with an air density of +150 ft but when the temperature drops below 20 F I start to see air density readings of -2000 ft and when it gets down to below 0 or below I see air density readings of -6000 ft. At a 1000 yards my groups were opening up considerably when it's cold. I was baffled why the same load was suddenly giving me fits until I ran the numbers with the Berger twist rate calculator and an elevation of -2000 ft it shows a 230 as marginally stable 1.42. At 1/8 twist gives you a 1.79. So I went to a lighter 215 Berger which is slightly more stable bullet for winter months until this barrel is wore out and I can get a 1/8 spun up for next year.
Where would you start for load development?“Best” is subjective. RL33 will be a little slow, and N565 will be a tad too fast for that bullet. N568 would be my choice for optimized velocity.
Thanks!
Not necessarily. I think it’s the best overall performing powder for a range of bullets in .300NM, but it’s notorious for reduced barrel life. I still use it though, but one of my barrels performs so well above others that I use N170 instead (less heat than N570), but that results in less velocity. So it really depends if you favor performance over barrel life.
N568 is a good alternative.
With a 250gr ATip and n570 I was comfortable enough to test 86.0, 86.5 and 87.0 and pick the best out of those.I just found 10 lbs of 570 that I forgot I had... Start at 77/78gr if I go with it instead?
What brass were you using?With a 250gr ATip and n570 I was comfortable enough to test 86.0, 86.5 and 87.0 and pick the best out of those.
It's a trigger tech special in an American rifle company CDG, it's got the trigger hanger so timing is easy to adjust.What kind of trigger do you have? Way back in the day, I would get light primer strike with a Timney trigger. Turns out the sear engagement was off on the trigger causing this issue.
That's kinda what I though with the tolerance stacking. I cut the chamber but didn't think it was long but the numbers don't lie.Your brass is growing near 0.010" and your seating primers 0.008" deep. I'm not surprised you're getting light strikes. Lapua brass shouldn't be 0065 short of gauge, then ur Smith cuts to go +003? Headspace sounds a bit deep. Stop seating your primers -008, only go to flush or max of -002 until your brass is formed.
The headspace isn't a big problem other than the fireform pains. Lapua is tough stuff and likely won't be fully formed for a few firings. Primer depth will make a difference on consistency of ignition.That's kinda what I though with the tolerance stacking. I cut the chamber but didn't think it was long but the numbers don't lie.
Saami was recently released. The 0.455 shoulder headspace datum line has a 0.010 range. Seems a bit excessive. If I were chambering a new 300nm barrel I'd prob use a new piece of brass as go, and chamber 0.003 deep of that.I just chambered a barrel and set headspace to my current lot of Peterson brass. The other 300nm I have on hand is chambered by Bartlein with an identical reamer and headspaced to the gauge. That barrel is .010” deeper than the one I did.
3151fps with 90gr of N570What are the speeds you guys getting with berger 220?
H1000 works great with the 215 gr. bullets but it's a bit to fast for the heavies. I can't find N570 so I've been using H50bmg and Staball HD(same burn rate as Retumbo).Ive looked all over the internet and can't seam to find anything on 245 eol bullets in a .300 norma with H1000. Seems like most guys are running N570. I have a couple jugs of h1000 and would like to stick with that if possible. Does anyone have any loads they would like to share with this bullet powder combo as well as velocity they are getting? I'm using Lapua brass. Thanks
Very interested in hearing your results with the ace barrels. They look like a great option with a great price. I'm guessing Unknownmunitions doing the work I also interested in hearing your thoughts on them.Any experience/ advice on loading for a 22” bbl’d 8 twist standard Norma in a hunting configuration?
Plenty of h1000, retumbo… still about 2 months left on my build, but I can’t stop thinking about loading.
Kelbly Nanook
22” ace 8twist
Manners Nimrod
UM bottom metal/ TT special
This is what is spec’d out at the moment. Wanting to run suppressed, hence the 22”