D
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I shoot the 230 SMK with Norma brass and 85.7 gr Retumbo seated .040 off the lands. Shoots under .5 MOA to 1000.
I'm looking at LRI's Mausingfield hunter setup and they have a number of options for the 300NM. I'm thinking the one I'll want is the "300 NORMA MAGNUM (.341 NECK / .235 FREEBORE)", but can someone confirm?
Options are:
300 NORMA MAGNUM (.344 NECK / .205 FREEBORE)
300 NORMA MAGNUM (.344 NECK / .172 FREEBORE)
300 NORMA MAGNUM (.341 NECK / .235 FREEBORE)
300 NORMA MAGNUM (.3415 NECK / .195 FREEBORE)
Planning on 230 hybrids but may try some 215s since I have some around
Options are:
300 NORMA MAGNUM (.344 NECK / .205 FREEBORE)
300 NORMA MAGNUM (.344 NECK / .172 FREEBORE)
300 NORMA MAGNUM (.341 NECK / .235 FREEBORE)
300 NORMA MAGNUM (.3415 NECK / .195 FREEBORE)
Planning on 230 hybrids but may try some 215s since I have some around
Wanting to try the 230smk but my barrel is only a 9 twist... Are you running a 8 twist barrel as stated from Sierra?
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D
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Yes mine is a 8 twist. You may be able to get away with a 9 depending on you altitude? I've heard of guys running 9 twist with the 230 SMK around here. Im in CO at 5300 feet.
I'm in CO also. It's a 29" tube so maybe I can get it to stabalize? I've been playing with the 225eld but sure like the sound of this 230 if I could get it to work... Appreciate the reply.
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Sure sounds pretty impressive.
Interested in the 215hybrid also... Just bought a partial box from a guy on here to give that a go.
Interested in the 215hybrid also... Just bought a partial box from a guy on here to give that a go.
How much case lengthening do you guys consider acceptable after firing virgin brass?
My unfired Peterson brass was measuring mostly 2.022 to 2.032 with most in the middle using my shoulder measuring tool. My fired brass is all 2.042 or 2.041. 20 thousandths seems like a lot of stretch to me in one firing.
Any input?
My unfired Peterson brass was measuring mostly 2.022 to 2.032 with most in the middle using my shoulder measuring tool. My fired brass is all 2.042 or 2.041. 20 thousandths seems like a lot of stretch to me in one firing.
Any input?
I'm about out of 230 Hybrids and need to buy some more. The 230s have performed well, but it seems like I have seen somewhere that the 215s were better. Does anybody have any data or experience with both? This is an AI AX with a 26" Broughton barrel. I'm just shooting steel at 1,500-2,000 yards.
Thanks!
Thanks!
I started a thread in the reloading section called "How Much Headspace Is Too Much?". I started it because I couldn't find any good answers to the question and my unfired brass was up to 20 thousandths short in my chamber. I wasn't sure if it was a chamber (SAC) or a brass (Peterson) issue.
As an added data point, I just measured 10 of my virgin Norma brand .300 Norma Magnum brass. They all measured 2.040 at the shoulder +/- .001 which would make them about perfect in my SAC chamber which is producing 2.042 fired brass.
It definitely looks like Peterson needs to refine the measurements in their .300 NM brass a bit. We will see if casehead failures are a problem for me later on.
On another note, I do plan on sticking with the Peterson brass. Is anyone interested in buying 100 pieces of unmodified and unfired Norma brass?
As an added data point, I just measured 10 of my virgin Norma brand .300 Norma Magnum brass. They all measured 2.040 at the shoulder +/- .001 which would make them about perfect in my SAC chamber which is producing 2.042 fired brass.
It definitely looks like Peterson needs to refine the measurements in their .300 NM brass a bit. We will see if casehead failures are a problem for me later on.
On another note, I do plan on sticking with the Peterson brass. Is anyone interested in buying 100 pieces of unmodified and unfired Norma brass?
That's some good info. You don't happen to know how lapua brass is coming in for length measured at the shoulder?
No, I haven't seen any of the Lapua brass yet. I think I saw something about it is only going to be available in loaded ammo initially and that hasn't hit the market yet.
Mine grew about the same. I heard somewhere that the Sami spec for 300 N is a wide margin and brass usually sits at the bottom and chaimbers usually sit at the top? I have no idea if that is true.
JP, my subsequent post (quoted below) sheds a bit more light on the issue. It seems my SAC chamber was about perfect for the shoulder length of the Norma brand brass. The Peterson brass is unfortunately a bit short but it was the first production run. @Supersubes said that Peterson is fixing the issue with the second production run and then all should be fine hopefully.
Yea I think there is something out of spec with the Peterson brass. I've pierced primers several times with them. Never pierced a single primer with Norma brass.
My primers (Federal 215 Magnum Match) are flattening extremely even though I am about 2 grains below 100% fill and even 100% fill isn't at max pressure for N570. I assumed it is either weak primers or possibly the fact that the casehead and primer have a 20 thousandths gap to expand into until the pressure stretches the brass to fill the chamber and seats the casehead and primer against the boltface.
Now that my brass is fire-formed to my chamber I will see if the primers flatten still the next time I shoot.
I am a big fan of Redding instant indicator and the unavailability of this tool for the 300 nm made me a little uneasy while starting handloading it. Do you think that the 338 lm version would be helpful to che shoulder bump and headspace? I don’t see any reason why it shouldn’t...
my peterson brass has done the same thing. My first 2 rounds didn't fire because of excessive headspace. I then got to measuring around and found they were .010 short. I called my gunsmith and questioned his headspacing. He assured me it was correct and as he is also my friend i took his word for it but the thought has been in my mind ever since. I am glad to hear this about there brass to ease that fear. I Jammed all of mine to basically fire form them without stretching the web so i should be good on brass life.
I would have done that too if I had figured out earlier what was going on.
At the range, the extractor on my DTA wouldn't catch the rim of the brass because the ejectors were pushing the casehead so far into the chamber. The range went cold before I fired my last round and I was unable to extract the live round. A RO had to babysit my rifle with a live round in the chamber (with the bolt back, magazine out, and safety on) while people went down range to service targets.
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Is this a specific lot issue with the Peterson? Or overall production. I have 250 new Peterson Brass that I haven't even opened up yet for my AXMC. I may need to do some measuring.
This is an issue with the first run of Peterson brass which is almost definitely what you have as Peterson has not released the second run of .300 NM brass as far as I know.
My Peterson fireforming experience was similar. With a mild load (83 gr. N570) the primers seemed a little too flatty for the load. I'll check the HS delta against unfired brass. Being in Europe, I have a box of Lapua brass (at least this time this one is the right side of the pond) on the shelf to compare with...let ya know.
Just bought a 300NM today. So I have spent the day learning so much from everyone who has contributed to this thread, thank you!
This has been a great help learning what loads to work up.
In putting an order together with one of my wholesalers I found this statement regarding Peterson brass in the 300NM.
NOTICE - THIS IS THE FIRST RUN: Due to popular demand, Peterson Cartridge released its .300 Norma Magnum and .338 Norma Magnum casings in the spring of 2018. When Peterson designed these casings, it chose to use the same parent casing as its .338 Lapua Magnum casing. As a result, Peterson chose to keep the major diameter of the casing (the diameter just above the extraction groove) the same size as its .338 Lapua Magnum casings. That diameter is .580”. Since Peterson has never had any complaints about excessive major diameter growth, or primer pocket loosening in its .338 Lapua Magnum casings, they believed that to be a fine decision.
After releasing its 1st production run of .300 and .338 Norma Magnum casings with a major diameter of .580”, it was brought to Peterson’s attention that some customers would rather the major diameter of the Peterson .300 and .338 Norma Magnum casings be the same size as the .300 and .338 Norma Magnum casings produced by Norma. That diameter is .583”.
Peterson has received a lot of compliments on its first run of .300 and .338 Norma Magnum brass. Customers have stated that the Peterson casings hold more pressure, and that they can get more reloads. Several have said things, like this customer who enthused, “The Peterson Brass I’ve been testing in .300 Norma Mag is by far the best .300 Norma Mag brass I’ve used to date. The accuracy is outstanding.”
After studying the potential problems associated with changing its .300 and .338 Norma Magnum major diameter, Peterson decided to modify its tooling to change the major diameter of its .300 and .338 Norma Magnum casings to match Norma’s major diameter which is .583”. As a result, all future production runs of Peterson’s .300 and .338 Norma Magnum casings will have a major diameter of .583” to match the Norma Magnum casings produced by Norma.
Steve
This has been a great help learning what loads to work up.
In putting an order together with one of my wholesalers I found this statement regarding Peterson brass in the 300NM.
NOTICE - THIS IS THE FIRST RUN: Due to popular demand, Peterson Cartridge released its .300 Norma Magnum and .338 Norma Magnum casings in the spring of 2018. When Peterson designed these casings, it chose to use the same parent casing as its .338 Lapua Magnum casing. As a result, Peterson chose to keep the major diameter of the casing (the diameter just above the extraction groove) the same size as its .338 Lapua Magnum casings. That diameter is .580”. Since Peterson has never had any complaints about excessive major diameter growth, or primer pocket loosening in its .338 Lapua Magnum casings, they believed that to be a fine decision.
After releasing its 1st production run of .300 and .338 Norma Magnum casings with a major diameter of .580”, it was brought to Peterson’s attention that some customers would rather the major diameter of the Peterson .300 and .338 Norma Magnum casings be the same size as the .300 and .338 Norma Magnum casings produced by Norma. That diameter is .583”.
Peterson has received a lot of compliments on its first run of .300 and .338 Norma Magnum brass. Customers have stated that the Peterson casings hold more pressure, and that they can get more reloads. Several have said things, like this customer who enthused, “The Peterson Brass I’ve been testing in .300 Norma Mag is by far the best .300 Norma Mag brass I’ve used to date. The accuracy is outstanding.”
After studying the potential problems associated with changing its .300 and .338 Norma Magnum major diameter, Peterson decided to modify its tooling to change the major diameter of its .300 and .338 Norma Magnum casings to match Norma’s major diameter which is .583”. As a result, all future production runs of Peterson’s .300 and .338 Norma Magnum casings will have a major diameter of .583” to match the Norma Magnum casings produced by Norma.
Steve
Steve, welcome to the .300NM club and we are pleased you are finding this thread useful.
While the notice from Peterson is interesting, it does not relate to the discussion we were having about the headspace being too short on their initial run of .300 NM brass. Hopefully, they resolved that issue too and it would be nice if they made a notice for that as well if they did resolve it.
Thank you McCrazy.
I believe the question was asked, but don't remember a definitive answer, can the SMK 230 be stabilized with the 300NM with a 1:10 twist? Their website says needs 9:1 or faster.
I had always thought it was about the rpm or the bullet. If you pushed it fast enough it could reach a stabilizing rpm and work fine. I could certainly see where it might not work in a 308/7.62 with a less than 9:1, but in the 300NM where it could be running around 2900 it would have the rpm to stabilize.
What are the facts??
Thanks,
Steve
I believe the question was asked, but don't remember a definitive answer, can the SMK 230 be stabilized with the 300NM with a 1:10 twist? Their website says needs 9:1 or faster.
I had always thought it was about the rpm or the bullet. If you pushed it fast enough it could reach a stabilizing rpm and work fine. I could certainly see where it might not work in a 308/7.62 with a less than 9:1, but in the 300NM where it could be running around 2900 it would have the rpm to stabilize.
What are the facts??
Thanks,
Steve
Take the specs of the 230 SMK and head over to the Berger Twist Rate Calculator: http://www.bergerbullets.com/twist-rate-calculator/ . That can at least help answer your question but there are other factors to consider as well. You are correct however that you gain stability with velocity, even using the same twist rate but it isn't a linear relationship.
I input the 230gr, .308 with a BC of .800 (and 1.715" long) into the calculator with the 1:9" twist and 2900 fps. At sea level and 59 degrees F, it is comfortably stable. With the same settings and changing to 0 degrees F, it is marginally stable and the calculator recommends a 1:8.5" twist rate. Something to consider if you shoot in the cold.
Sierra recomend 8 twist or faster.their 230 is but longer than 230hyb..i guess im ok with my 9.25-8.5 gain twist.since we never go below 60° here
Any other thing to remember is changing the altitude when you get into the really cold temps. I had a buddy from FL and when he was in putting 0 degrees he left it at sea level instead of 7000ft where I'm at for when he comes to CO to shoot. Not sure where or when it gets to 0 degrees F in Florida. Needless to say he was ok with what he had and what he was shooting.
BJay,
Won't have my rifle until Wednesday, but I believe it will have a 1:10.
What are you shooting with that twist?
Steve
Won't have my rifle until Wednesday, but I believe it will have a 1:10.
What are you shooting with that twist?
Steve
Im testing both 230 smk and 198 right now..im going to stretch them to a mile this weekend and see...trust me if you love shooting here in paradise....youll have to pay..primers and powders are gold here lol. IF! they even make it
So Gents, here are my numbers.
Peterson unfired brass lot #W1AR0090 2.060"
Fireformed as per the above charge 2.068"
Lapua Lot#80111401/0661018 unfired 2.066"
Hornady gauge, 420 datum.
The headspace on the Peterson unfired is only .006 less than the lapua so the guys that are seeing ,020+ growth in headspace on there Peterson brass must have max spec chambers. gnatmm, the virgin lapua brass is matched up perfect to your chamber. What are the major diameter measurements on the virgin lapua and Peterson brass that you have coming in at?
It is worth re-mentioning that my virgin Norma-brand brass is only 2 thousandths shorter than my fire-formed Peterson brass. You would need to bump the shoulders back on brand new Norma brass to make it fit in Gnat's chamber.
There seems to be a big range in the specs on the NM chamber. I have a Christensen Arms MPR in 300NM on order, I can get lapua brass and I had planed to get the redding fl bushing die so hopefully that combo works out ok. Christensen says they use a match reamer. I don't like the brass stretching to much on the first firing and dies that don't match up to the chamber size wise. I really like the redding competition shell holders for setting the head space but the chambers headspace and the die headspace have to be with in .010 for them to work.
I am also using Redding type s fulls size bushing die, my first time with that and I am quite happy with it. ( usually I use Forster FL and a 21Century turning mandrel for my creed and 308 handloading. ) I did not spare on bushings (I got the whole range .339-.334) because Pet loaded round are .340-.341 while Lapua se a little less at .338-.337 and I am not going to neck turn .300 Norma for the time being, even if I got 21C bits for it.
I would like to order my reloading bushing for the 300NM before I actually have the bullets and cases to measure the OD of the case neck. New caliber for me so the components are on their way.
Does anyone know what their bushing is or the OD of the loaded case neck with Peterson brass and the Berger 230 bullet?
Thank you,
Steve
Does anyone know what their bushing is or the OD of the loaded case neck with Peterson brass and the Berger 230 bullet?
Thank you,
Steve
I'm doing 2.485.
Max is 2.502.
Looks like Berger recommends trimming to 2.490.
All my brass is Norma.
I'm doing .337 on Norma brass.
Sounds like most guys are using a .336
So if I take these numbers, is it possible that is why that I cannot see a mesurement difference when I try to FL size my new Lapua brass?
I have the Hornady comparator (.420) and the Whidden (.450). Mesure at 2.067. Set-up the fl die, run the brass and still get the same mesure, even if I screw the die until I cannot cam-over.., Btw I use Forster did
I have the Hornady comparator (.420) and the Whidden (.450). Mesure at 2.067. Set-up the fl die, run the brass and still get the same mesure, even if I screw the die until I cannot cam-over.., Btw I use Forster did
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