300NM vs 338LM

B

Beeckie

Private
Minuteman
Dec 7, 2017
32
3
#1
Ok I’m looking to build an new rifle to shoot 2000 yards. I’m contemplating a 300NM or a 338LM.
My reasoning:
300NM
Pro: uses affordable .30 cal bullets and great ballistics
Con: barrel life

338LM
Pro: barrel life, it’s a 338LM ?
Con: expensive .338 cal bullets

What are your thoughts.
 
  • Like
Reactions: Supersubes
#3
You can knock on the door of 300nm performance with the 300 PRC with less powder and one would assume better barrel life. Also fits a standard magnum bolt face. Still fairly new, just got saami approved but it's going to be supported by Hornady and others going forward.
 
#4
Ledzep said:
You can knock on the door of 300nm performance with the 300 PRC with less powder and one would assume better barrel life. Also fits a standard magnum bolt face. Still fairly new, just got saami approved but it's going to be supported by Hornady and others going forward.
Click to expand...
I've shot the 300 PRC side by side with a 338 Lapua in the gentle Nebraska breezes at 2K. Blowing 17-20 that day. I did not feel under gunned. And yes I have a 300 Norma also but I'd rather throw 75-80 grs. of powder in the case vs 90+
Speaking in pure accuracy terms 30's will always be more accurate than a 338.
 
  • Like
Reactions: Sig Marine, AMP!, bjay and 3 others
#5
Unless I can step up to something like a 416 Barret custom rifle, to really take advantage of that cartridges abilities as far as ELR, I'll stick with the 300PRC powder capacity like Dave mentioned. The recoil is relatively soft and the concussion with a brake is mild.
 
#6
DAVETOOLEY said:
I've shot the 300 PRC side by side with a 338 Lapua in the gentle Nebraska breezes at 2K. Blowing 17-20 that day. I did not feel under gunned. And yes I have a 300 Norma also but I'd rather throw 75-80 grs. of powder in the case vs 90+
Speaking in pure accuracy terms 30's will always be more accurate than a 338.
Click to expand...

17-20 is a gentle breeze here in Nebraska :)

I' m working up a 300 norma load now for my DT. I chose the 300 norma over 338 because of the wide 30 cal bullet selection, and slightly less "cha-ching" per trigger pull.
 
#7
I’d like to do an ELR build on a Desert Tech one day and looked at both cartridges. The 300NM is a good performer but barrel life is a killer. At the cost of a DT Barrel, what is the trade off between cheaper bullets but needing a new barrel a lot sooner. Think those .30 bullets become more expensive over time when a new barrel is needed and the 338 keeps going.

As far as Accuracy, I previously owned a 338LM built on a Defiance and it was pretty damn accurate. Idk that you lose anything with either one.
 
#9
ChadL said:
17-20 is a gentle breeze here in Nebraska :)
I' m working up a 300 norma load now for my DT. I chose the 300 norma over 338 because of the wide 30 cal bullet selection, and slightly less "cha-ching" per trigger pull.
Click to expand...

I wonder how it works out once you factor in barrel life as part of the cost of each round being fired.
Assuming you are reloading, the difference might not be much if the .338LM has double the barrel life of the .300NM
(Which it what it seems to easily be).
 
#10
W54/XM-388 said:
I wonder how it works out once you factor in barrel life as part of the cost of each round being fired.
Assuming you are reloading, the difference might not be much if the .338LM has double the barrel life of the .300NM
(Which it what it seems to easily be).
Click to expand...
Barrel life wasn’t a factor for me as I anticipate only shooting 200-300 rounds a year with my 300 Norma. I get what you’re saying though. Reloading cost between the two was something I did consider.
 
#11
Stag556 said:
I’d like to do an ELR build on a Desert Tech one day and looked at both cartridges. The 300NM is a good performer but barrel life is a killer. At the cost of a DT Barrel, what is the trade off between cheaper bullets but needing a new barrel a lot sooner. Think those .30 bullets become more expensive over time when a new barrel is needed and the 338 keeps going.

As far as Accuracy, I previously owned a 338LM built on a Defiance and it was pretty damn accurate. Idk that you lose anything with either one.
Click to expand...
I have both in desrttech. Likee my 300 norma better!
 
#13
The way cup and core bullets are made leaves more chance for concentricity errors in the core than the cup. Simply less control in forming it. More likely to be pockets, inclusions, more likely to have a greater effect because of higher density if something is formed a little off center... The core grows as a percentage of the total mass of the projectile as you increase diameter. That's my theory on it anyway, and for now I'm sticking to it.

Not saying it's impossible to make big bullets well, just that it often takes maybe a little more massaging than a .224 55gr flat base varmint bullet.
 
  • Like
Reactions: PBWalsh
#15
PBWalsh said:
I am a die hard .30 cal fan, but this statement interest me. Dave, in your opinion and experience, how would a match .30 cal projectile be more accurate than a match .338 cal projectile?
Click to expand...

This goes back to my 1000 Yd benchrest days. Which I consider the gold standard for evaluating pure accuracy, not driver accuracy. I was working with AI on PRSI. I had data for 15 years of competition by caliber. That's a lot of good real world data. The heavy gun class had no weight limit so recoil was not an issue. 1% of the groups were shot with a 338 in 15 years. The 338's couldn't keep up with the 30's. I had/have a customer who tried every trick in the book to make a 338 competitive. He had his occasional flash of success but no consistency week to week. He gave up several times but in a year or two the pain would subside and he'd have another go at it. Same results. Pure and simple it's about bullets. I once had some Sierra 300's that would hold .5 MOA. @1K That was a long time ago. The 1st gen Berger 300's were probably the best. Berger changed that bullet because they were blowing up when pushed to 3000+ FPS. I won't get into all the subtleties of bullet making but there are always compromises. It's just easier to make a 30 vs a 338 bullet. Nowadays the 6.5's and 6MM's have taken over because of good bullets. You have to have a rifle capable of shooting .250 MOA to be in the hunt on a day with good conditions. I set the IBS heavy gun group record in 2006. 4.322" 10 shot group. Nothing remarkable about that in today's world. That held as the record for 4 or 5 years. I was shooting a 30 cal 187 gr. flat base bullet. That bullet made my life very easy. It shot well, every lot shot well. Most consistent performer I've ever seen. Years later one gentleman who laughed at my suggestion of using a FB bullet @1K set a new record using, guess what, those FB bullets. Give me enough BC, enough velocity and most important, accuracy then I can learn to shoot. Just an educated opinion but in most cases you give up about 20% in baseline accuracy shooting a 338.
 
Last edited:
  • Like
Reactions: Hank Fabich jr. and PBWalsh
#16
Thank you for the detailed reply, FB bullets still throw me for a loop when compared to longer boat tail bullets. But they seem to do very well at shorter range BR comps.
 
#17
I've owned 6 sets of bullet dies. I still have two sets. I know making a very good FB bullet is easier than making a very good BT.
Those 187's had a BC of around .525 That's enough BC when coupled with extremely good accuracy to get to 1K. I never shot them past that.
We had some killer FB 140 gr. 6.5's until something changed in the jackets. Then we had disappearing bullets in several rifles.
 
  • Like
Reactions: PBWalsh
#18
DAVETOOLEY said:
This goes back to my 1000 Yd benchrest days. Which I consider the gold standard for evaluating pure accuracy, not driver accuracy. I was working with AI on PRSI. I had data for 15 years of competition by caliber. That's a lot of good real world data. The heavy gun class had no weight limit so recoil was not an issue. 1% of the groups were shot with a 338 in 15 years. The 338's couldn't keep up with the 30's. I had/have a customer who tried every trick in the book to make a 338 competitive. He had his occasional flash of success but no consistency week to week. He gave up several times but in a year or two the pain would subside and he'd have another go at it. Same results. Pure and simple it's about bullets. I once had some Sierra 300's that would hold .5 MOA. @1K That was a long time ago. The 1st gen Berger 300's were probably the best. Berger changed that bullet because they were blowing up when pushed to 3000+ FPS. I won't get into all the subtleties of bullet making but there are always compromises. It's just easier to make a 30 vs a 338 bullet. Nowadays the 6.5's and 6MM's have taken over because of good bullets. You have to have a rifle capable of shooting .250 MOA to be in the hunt on a day with good conditions. I set the IBS heavy gun group record in 2006. 4.322" 10 shot group. Nothing remarkable about that in today's world. That held as the record for 4 or 5 years. I was shooting a 30 cal 187 gr. flat base bullet. That bullet made my life very easy. It shot well, every lot shot well. Most consistent performer I've ever seen. Years later one gentleman who laughed at my suggestion of using a FB bullet @1K set a new record using, guess what, those FB bullets. Give me enough BC, enough velocity and most important, accuracy then I can learn to shoot. Just an educated opinion but in most cases you give up about 20% in baseline accuracy shooting a 338.
Click to expand...
probably not something you have data on, but say i were to shoot only solids through a 300NM or 338LM, does the 338 still lose here?
 
#20
PBWalsh said:
@Ledzep

So theoretically thats why you see 6mm cartridges whooping tail at BR comps?
Click to expand...

Yeah. I mean look at what's going on. You're taking a piece of copper tube with lead inside of it and spinning it at 200,000-300,000rmp. It's a different animal but look at how little mass it takes out of balance in an engine's rotating assy., or on your tire, or in a machine spindle to make things wobble to beat hell at less than 10,000rpm.

So in forming a bullet you're trying to make 2 or 3 shapes (Ogive, bearing surface, and potentially a boat tail) have their center of mass lie on exactly the same center axis, then spin the whole thing exactly about that center of mass. Accuracy, as far as bullet manufacturing goes, is in concentricity. There are some other finer points, but bad concentricity will wreck things in a hurry.

It's been no secret for decades that flat base bullets are easier to get to hammer through the same hole. That's theoretically two-part-- One is forming a concentric bullet, the other is gas expansion on the muzzle end. With a flat base you have 1 less feature to make concentric in production, and it's much more forgiving to crown geometry/gas expansion. The trade-off is lower BC.

So back to my earlier point, jackets get ironed in several step processes in drawing them out and it's controllable for concentricity to within ten-thousandths of an inch (well really, as tight as you care to fiddle with it). Cores, however, are not directly formed by tooling, they are indirectly formed by swaging operations inside the jacket. So with big and small bullets, you're going to spin them the same RPM, and the jacket concentricity is more or less equal, it's just a matter of how much core mass and how far from the center axis it is, and the bigger you get, the bigger that is. So the more dense part of the bullet is making up a greater percentage of total weight, is formed less directly, and defects have more mass and are further and further from the center.

Knowing what I know now, but having never participated in BR, it seems of natural course that something like the 6 BR or 6 PPC shooting flat base bullets was developed for pure accuracy. Moderate cartridge with flat-base match bullets, then go full lab-grade on every aspect of prep.
 
  • Like
Reactions: Mj1995, AMP! and PBWalsh
#21
The two manufacturers I'm very familiar with are Sierra and Hornady. Each approaches cores and bullet assembly slightly differently. Each extrudes lead wire in large hydraulic presses to the appropriate size.

Sierra makes their jackets on a separate press starting with rolls of gilding metal of different thicknesses. From these rolls short large diameter cups are made then they go through the jacket press and finish jackets are drawn. The spooled lead wire is fed into the bullet press and a buck of jackets is loaded into a feed hopper. This press takes the wire, cuts it to length and runs into a squirt die to bleed off excess weight. It's then dropped into the jacket and the bullet assembly begins.

Hornady extrudes the same lead wire. Then it's fed into a stand alone press that makes the cores. Jackets start out the same. A roll of gilding metal and rough cups are punched out. The finished cores and the large diameter cup for the jacket are then fed into a press where the jacket is drawn to diameter, taper and trimmed to length. Then the core is inserted and the bullet assembly begins. All on one press.

Slightly different approach but each company ends up in the same place.
 
#22
b6graham said:
probably not something you have data on, but say i were to shoot only solids through a 300NM or 338LM, does the 338 still lose here?
Click to expand...

I no data on solids. They are a totally different animal. I have some here to try in my 300 PRC as soon as they harvest the corn. Hoping to establish a range where I can shoot year round. Plenty of room down here. I drive past one spot that's dead flat and mile long down an agricultural road. Lots of places like that.
 
  • Like
Reactions: b6graham
#24
DAVETOOLEY said:
The two manufacturers I'm very familiar with are Sierra and Hornady. Each approaches cores and bullet assembly slightly differently. Each extrudes lead wire in large hydraulic presses to the appropriate size.

Sierra makes their jackets on a separate press starting with rolls of gilding metal of different thicknesses. From these rolls short large diameter cups are made then they go through the jacket press and finish jackets are drawn. The spooled lead wire is fed into the bullet press and a buck of jackets is loaded into a feed hopper. This press takes the wire, cuts it to length and runs into a squirt die to bleed off excess weight. It's then dropped into the jacket and the bullet assembly begins.

Hornady extrudes the same lead wire. Then it's fed into a stand alone press that makes the cores. Jackets start out the same. A roll of gilding metal and rough cups are punched out. The finished cores and the large diameter cup for the jacket are then fed into a press where the jacket is drawn to diameter, taper and trimmed to length. Then the core is inserted and the bullet assembly begins. All on one press.

Slightly different approach but each company ends up in the same place.
Click to expand...
Interesting... I had ASSumed that jackets were filled with molten lead (to a certain level), then the final shaping of core and jacket alike were done once the lead re-solidified. Shows what I (don't) know.
 
#25
BurnOut said:
Interesting... I had ASSumed that jackets were filled with molten lead (to a certain level), then the final shaping of core and jacket alike were done once the lead re-solidified. Shows what I (don't) know.
Click to expand...

You get better geometric uniformity swaging cores. Bonded hunting bullets melt the cores in the jacket but the lead cools and contracts a little-- makes some goofy shapes sometimes-- and isn't necessarily conducive to the utmost precision. There are work-arounds but it's its own can of worms. The primary goal with those bullets is on the terminal side of things, while maintaining acceptable accuracy. And that's not to say they shoot bad. Most people/rifles probably can't shoot the difference consistently enough to notice it.
 
#26
BurnOut said:
Interesting... I had ASSumed that jackets were filled with molten lead (to a certain level), then the final shaping of core and jacket alike were done once the lead re-solidified. Shows what I (don't) know.
Click to expand...

My die sets are made up of three dies. One to take wire cut to length and squirt the cores. A core seating die which takes the slightly undersize cup/jacket with the core and expands the cup and core combo up to size with a precise fitting punch inside the jacket. Then the point up die which forms the ogive.

Hornady and Sierra will give tours. If you're planning a trip past either call ahead and schedule a visit. It would be well worth your time.
 
#28
#32
Yes, long action, magnum bolt face. Imagine a non-rebated rim 300 RUM short enough to load long(er) bullets to magazine length, and a powder column that's the right size to have decent fill & with available powders (read; efficiency).

225gr bullet at 2900-2950fps out of a 26" barrel was what I saw. Loads were at or under SAAMI max pressure. Myself and one other shooter (the owner) threw 10 rounds (5 each) into one .7" hole at 100yd.
 
Last edited:
#35
The Nosler has a rebated rim (.534" rim and .550" body at the base), so it's a little bigger around, and it has a 35 degree shoulder vs. 30 degree on the PRC. They're very similar otherwise, as far as the cases go. Where the shoulder begins is within .006" and about the same neck length.

The 300 PRC Chamber has a longer free bore. .110" vs. .232". For ammunition, the SAAMI spec has the PRC @ 3.700 and the Nosler at 3.346, but if you're reloading and throat reaming it's kind of arbitrary.
 
#37
DAVETOOLEY said:
I've shot the 300 PRC side by side with a 338 Lapua in the gentle Nebraska breezes at 2K. Blowing 17-20 that day. I did not feel under gunned. And yes I have a 300 Norma also but I'd rather throw 75-80 grs. of powder in the case vs 90+
Speaking in pure accuracy terms 30's will always be more accurate than a 338.
Click to expand...
What did you see with the nm ? Improved?
 
You must log in or register to reply here.

Similar threads

M
300nm or 338lm
Replies
19
Views
366
mattman215
M
B
.300WM to .338LM Chassis Modification Possible?
Replies
15
Views
269
Wannashootit
W
Blythe Wurster
sig cross sawtooth vs. bergara HMR pro
Replies
12
Views
519
Blythe Wurster
Blythe Wurster
Dogtown
SOLD ES Tactical Barrels for DT SRS - .300NM & .338LM Improved 40
Replies
5
Views
333
culater
C
S
300 WM vs 338LM Barrel Life and reloading cost
Replies
7
Views
412
secondofangle2
secondofangle2
Top Bottom
Back
Home
Forums
Merch
Alerts