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.
What is the recommended "Trim To" length for 300 NM ?
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 settled on .336 with Peterson brass. My loaded ammo is .338 so the .336 gives me a couple thousandths of neck tension.
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
Thanks @wilson3899
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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
Take a piece of your new brass and see if it will chamber in your rifle. If it does (and it should), measure it and record the length with your comparator. Load it and fire it, remeasure with your comparator. The difference between the two will be how much your brass is stretching to fill your chamber. The fired brass gives you the headspace on your chamber. Now when you set up your die only bump the headspace back on the fired brass by .002
You will likely find that the headspace on your new brass is going to grow enough that you will be able to set up your die.
It isn't a bad idea to check again after your second firing and tweak your die set up if needed. Sometimes your headspace might be just a little longer than your first firing and to keep your die bumping your headspace by only .002 you might just have to raise it another thou or two.
Thanks! Its usualy what I do also. But found strange and its a first time for me, that I am not able to size a new brass in a FL die.
You don't want to bump the shoulder back on new brass at all if it will chamber as is in your rifle or it will just have that much further to stretch when you fire it. That can increase the chance of case head separation down the road.
Totaly understand that. Just wanted to size them equal so that I can neck turn them
I just received my AXMC and have shot it 50 times a day in the last three days, 150 total. I have cleaned after each 50 and thought the amount of carbon fouling was normal. I have not seen any abnormalities with "rings." I have never seen them.
I was surprised when I cleaned for copper fouling and the patch was only very slightly blue after the first 50. I guess the better the bbl the less copper fouling.
Possible higher pressure in my AXMC upon 3rd reloading round count 100-150......
I have been shooting my AXMC, Peterson brass, Fed match mag primers, 92.6g RL33, with a Hornady 225 ELD Match bullet.
My first 50 rounds were different loads a few .10th up and down from this load with the Hornady bullet and Berger 230's. No signs of high pressure. Realized that the bbl was brand new and I should get used to the rifle and let the bbl break in a little. OK I wanted to shoot steel and after a great group at 100, thought I would have some fun from 300 to 1,000.
Cleaned bbl and reloaded another 50 with the Honady bullet and 92.6g of RL33.
Shot the next day, steel from 300-1,000 and found that I was shooting .8 mils high, adjusted and everything went well. Don't know why the raise in POI. Reloads all seem normal.
Cleaned bbl and load 50 more same load as previous.
Shot 500-1200 yards and was able to move between each target and hit consistently. No POI move or change in DOPE. Wind gusting and changed directions 90 deg.
POI same as previous day but pressures seemed higher. Noticed the primer had a little more of a crater than before and a very slight shinny spot. Less than the pic in post #253 in this thread. The bolt was SLIGHTLY harder to close on a couple shots and never hard to open. I will measure case length and compare to new Peterson brass this evening.
I ran the LabRadar with most of the 150 rounds fired. And the velocities are all pretty close. Most of the increase of maybe average of 50 FPS faster happened in the 50 shots. No difference in the last 50 from the prior 50. My wholesaler was out of the 8lbs keg of powder so I bought 5 1 lb containers. Will check to see if the powder is from different lots.
Any idea why the pressures might be up?
Different lots of powder?
Should I be concerned?
The rifle was still shooting great, at least for me.
LOVE the 300NM round and the AXMC!
Thanks,
Steve
I have been shooting my AXMC, Peterson brass, Fed match mag primers, 92.6g RL33, with a Hornady 225 ELD Match bullet.
My first 50 rounds were different loads a few .10th up and down from this load with the Hornady bullet and Berger 230's. No signs of high pressure. Realized that the bbl was brand new and I should get used to the rifle and let the bbl break in a little. OK I wanted to shoot steel and after a great group at 100, thought I would have some fun from 300 to 1,000.
Cleaned bbl and reloaded another 50 with the Honady bullet and 92.6g of RL33.
Shot the next day, steel from 300-1,000 and found that I was shooting .8 mils high, adjusted and everything went well. Don't know why the raise in POI. Reloads all seem normal.
Cleaned bbl and load 50 more same load as previous.
Shot 500-1200 yards and was able to move between each target and hit consistently. No POI move or change in DOPE. Wind gusting and changed directions 90 deg.
POI same as previous day but pressures seemed higher. Noticed the primer had a little more of a crater than before and a very slight shinny spot. Less than the pic in post #253 in this thread. The bolt was SLIGHTLY harder to close on a couple shots and never hard to open. I will measure case length and compare to new Peterson brass this evening.
I ran the LabRadar with most of the 150 rounds fired. And the velocities are all pretty close. Most of the increase of maybe average of 50 FPS faster happened in the 50 shots. No difference in the last 50 from the prior 50. My wholesaler was out of the 8lbs keg of powder so I bought 5 1 lb containers. Will check to see if the powder is from different lots.
Any idea why the pressures might be up?
Different lots of powder?
Should I be concerned?
The rifle was still shooting great, at least for me.
LOVE the 300NM round and the AXMC!
Thanks,
Steve
Thank you SAP.
It was fine until the third firing. Upon the third firing I felt like I had a higher pressure issue.
Steve
It was fine until the third firing. Upon the third firing I felt like I had a higher pressure issue.
Steve
Different lots of powder can have a substantial variance in burn rate. I have seen it on more than one occasion and tested it to confirm.
The other thing I would check for is a donut in your brass. Try sliding a bullet in your fired brass and see it jambs at the neck shoulder junction.
What length of barrel and what velocity are you getting with that load?
Thanks BClrh
I was able to slide a bullet in the empty case, no issues. Didn't see any deformity in the neck.
27" bbl 3020 FPS was the average.
case grew .012" in three firings.
I think I forgot to mention I only neck resized and it was at .338. That was the OD of a new case, so I started there.
I was able to slide a bullet in the empty case, no issues. Didn't see any deformity in the neck.
27" bbl 3020 FPS was the average.
case grew .012" in three firings.
I think I forgot to mention I only neck resized and it was at .338. That was the OD of a new case, so I started there.
maybe case growth? if the brass is substantially longer after the 1st 2 firings (you say 0.012"), it could "pinch" the bullet in the lead area of the chamber, thereby causing pressure?
I am wondering the same. I don't know. I have read, but not experienced , higher pressures when the bullet has no jump.
I have the bbl out and just finished cleaning. I don't have the 300NM comparator case for the Hornady Bullet seating depth measurement so I am placing a bullet in the case and pushing it into the chamber by hand. Just started. I will see if the seating depth I was using took all my jump out after it grew .012....
Thank you very much SAP.
I have the bbl out and just finished cleaning. I don't have the 300NM comparator case for the Hornady Bullet seating depth measurement so I am placing a bullet in the case and pushing it into the chamber by hand. Just started. I will see if the seating depth I was using took all my jump out after it grew .012....
Thank you very much SAP.
OK I measured the oal with the fired case and with the bullet touching I have an oal of 3.612 and I was loading to an oal of 3.51. So I don't believe a too short jump was the issue....
Thanks SAP
Thanks SAP
Check into this. Your subsequent post speaking of your COAL does not address this concern. What you need to do is measure your brass OAL. The shoulder gets bumped forward during firing and your neck also gets longer as brass migrates forward from the web. If your brass was trimmed to length or shorter than the trim-to-length prior to your initial firing, it may be well beyond this trim-to-length by now. Comparing your fired brass to your unfired Peterson brass is also largely irrelevant other than for comparison sake. What matters is the length of your brass compared to the recommended trim-to-length and even more importantly the cut of your chamber.
You mentioned the bolt being slightly harder to close but not to open:
This may be because your brass is now longer than the chamber is cut for. If it is longer at the shoulder (quite likely since you said you have been neck-sizing with no mention of shoulder bumping) it will make it harder to close the bolt but there will also be resistance when you open the bolt after firing. However, if the neck is exceeding the area of the chamber that is cut out for it, it may be protruding into the throat where it is being squeezed by the barrel (causing the tension you feel) and then your brass is squeezing the bullet which increases your effective neck tension and can cause pressure spikes like you are experiencing.
As for seating depths, touching the lands leads to higher peak pressures as well since the bullet doesn't get a running start prior to hitting the lands. Think of the difference between hopping a curb in a truck when the truck is already rolling versus the truck being stopped and having to power over the curb.
Thanks again SAP and McCrazy,
I have never run into this problem before and I have only neck sized my 300WM and 260Rem in bolt guns, full length size in the gas guns. So new to me. Thanks for the help.
After 3 firings it grew .012" OAL from the new brass.
I placed the fired cases in the bbl and compared to the new brass. Easy to do/see with the bbl pulled. It does look like the fired brass doesn't enter the chamber as far.
I have never bumped necks back. I am pretty sure I am running the brass as far as I can in the neck sizing die and I'm not bumping the neck, so I assume I need to full length resize? If this is the case then I will have a case that is not formed to my chamber the next firing and will possibly change the POI slightly??
I am aware of the higher pressures with the bullet touching the lands. Thought that might be the issue as I didn't know how much of a jump I had until last night when figured it was .1.
Had never considered the increased neck pressure due to the case protruding into the throat. Makes perfect sense to me now. Thank you for taking the time to explain it. Sorry SAP if that is what you were saying and I didn't understand.
I ordered a case trimmer a couple days ago, not here yet. I will trim and see how that effects the fit of the case into the chamber. My GUESS is that it will be the shoulder.
Do I need to full size every so often to bump back the neck? Looks like in two firings for this load.
What would you do??
Thank you,
Steve
I have never run into this problem before and I have only neck sized my 300WM and 260Rem in bolt guns, full length size in the gas guns. So new to me. Thanks for the help.
After 3 firings it grew .012" OAL from the new brass.
I placed the fired cases in the bbl and compared to the new brass. Easy to do/see with the bbl pulled. It does look like the fired brass doesn't enter the chamber as far.
I have never bumped necks back. I am pretty sure I am running the brass as far as I can in the neck sizing die and I'm not bumping the neck, so I assume I need to full length resize? If this is the case then I will have a case that is not formed to my chamber the next firing and will possibly change the POI slightly??
I am aware of the higher pressures with the bullet touching the lands. Thought that might be the issue as I didn't know how much of a jump I had until last night when figured it was .1.
Had never considered the increased neck pressure due to the case protruding into the throat. Makes perfect sense to me now. Thank you for taking the time to explain it. Sorry SAP if that is what you were saying and I didn't understand.
I ordered a case trimmer a couple days ago, not here yet. I will trim and see how that effects the fit of the case into the chamber. My GUESS is that it will be the shoulder.
Do I need to full size every so often to bump back the neck? Looks like in two firings for this load.
What would you do??
Thank you,
Steve
Steve,
To be honest, I used to neck size and then only bump the shoulder when needed but that allows an ever larger variance in your loads and you end up running into bolt closure issues at times. Now, I just bump the shoulder back a couple thousandths and full-length resize every firing.
If I give up any sort of accuracy, it is marginal and insignificant to me. The consistency of having the same reloading process every time and having rounds that are the same every time and properly chamber is more important to me.
If you have a match chamber, the full-length resizing won't be moving the brass very much anyways compared to brass fired in a sloppy factory chamber.
To be honest, I used to neck size and then only bump the shoulder when needed but that allows an ever larger variance in your loads and you end up running into bolt closure issues at times. Now, I just bump the shoulder back a couple thousandths and full-length resize every firing.
If I give up any sort of accuracy, it is marginal and insignificant to me. The consistency of having the same reloading process every time and having rounds that are the same every time and properly chamber is more important to me.
If you have a match chamber, the full-length resizing won't be moving the brass very much anyways compared to brass fired in a sloppy factory chamber.
I use the Redding Type-S Match Bushing 3-die sets with Competition Seaters like these: https://www.brownells.com/reloading...-s-match-bushing-neck-die-sets-prod38164.aspx
How much were you jumping the bullet with this load
I used new brass and the pressures were high, holes in primes. Shot a Hornady factory round, high pressure and hole in primer.
I started a new thread in the bolt guns discussion forum in the event that this wasn't the proper place to continue with this personal issue.
Thanks,
Steve
Anybody shot one of these barrels out yet besides me? Mine was done at 649 rounds.
That's not many rounds. Any details? Load you were using, velocity, barrel length. Did you have it bore scoped?
I shot 84gr of h1000 225eldm and then switched to 86.5 gr of h1000 215 bergers for the rest of the time. Was averaging 3090 with the bergers. Barrel length is 26 inches. Yes I bore scoped it. It looks rough.
That's to bad. With h1000 and pushing 215's at 3090, which shouldn't be extreme pressure, you would think that you would get 900 to 1100 rounds. 650 is less than a RUM usually gets.
Only thing I can figure is that a shot it pretty hot a few times this past summer in hot weather and that started the process of it burning up quicker.
Wait...what. You shot out a 300NM barrel in less than 650 rounds?
Besides the borescope, how was it shooting?
Were you getting the barrel really Hot and not allowing cool down every 5 rnds or so?
Your loads don't seem like hot loads at 84-86grns..cleaning regiment?
Well , 300winnies are only good for about the same when they are runned hot...600-1000rnds
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Not good. I was shooting at 1627 yards on a pretty much windless day at my 24 inch plate and one shot would hit the plate then the next would hit 2 moa in front of the plate. It went back and forth the whole time doing that.
There were a few times I let it get pretty hot were it was too hot for me to touch the barrel. Not many, may about 5 times, but I guess it only takes maybe one time getting it that hot for it to stop shooting?
The reason i ask it's because a friend of mine ran his 300 Dakota hot many times and after approx.600 rnds the barrel showed alot of errosion and heat cracks for the 1st few inches of the throat area and the last 3 inches of the muzzle end.however last time a shot it,it still printed 1/2 moa at 100 yards for 5 rnds. at 26 inches you can still set the barrel back a couple inches and still get decent fps and barrel life.
ok thank you. I may look into it again, but it didn't look good the other day.
Don't get your hopes up. With cartridges that kill barrels with fire cracking rather than slowly wearing them out, they loose the ability to hold vertical at distance before the 100 yard groups open up much. I'm not sure if they're not engraving the bullets consistently anymore, or just tearing them up. If you had calm conditions and a chrono that verified the velocity spreads you were expecting, that vertical is the barrel going south. It's also easy to write it off to having a bad day, but when was the last time you shanked several shots in a string 2 moa at 100 yards? It just doesn't happen.
The minimum chamber length on the CIP 300 Norma drawing is 2.502"
The maximum case length is 2.492"
The recommended case trim to length is generally 0.010" under the maximum case length. That would be 2.482"
There isn't a SAAMI specification for the 300 Norma.
I'm having the same trouble with the Peterson brass others have reported. It is .006" to 0.014" shorter than my Manson 300 Norma Go Gauge. Norma was .004"-.006" shorter, which is pretty typical for new brass.
The maximum case length is 2.492"
The recommended case trim to length is generally 0.010" under the maximum case length. That would be 2.482"
There isn't a SAAMI specification for the 300 Norma.
I'm having the same trouble with the Peterson brass others have reported. It is .006" to 0.014" shorter than my Manson 300 Norma Go Gauge. Norma was .004"-.006" shorter, which is pretty typical for new brass.
Mine was really short, grew .020 on the first firing, but gave me no trouble and shot well. A couple didn’t want to let the extractor grab them but my ejector spring was very stout. I’m thinking that would have happened on any brass that wasn’t squished into the chamber. I trimmed the spring and it grabbed every one after that. I’m prob going to trim a little more as it still flings the brass really hard. I put a strip of adhesive suede/leather on the side of my action because the brass was beating the crap out of it and chipping the cerakote when the ejector throws it out.
I also annealed after the first firing to make sure the brass didn’t get worked too hard.
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