.30-06 vs .308

[Bart B.]

Here's what can be done with a 308 shooting 155's at 800 yards:

Maybe things have changed, but the '06 was commonly loaded to 50,000 psi; the .308 to 55,000 psi.

Not so Art.

Arsenals and commercial plants loaded the 30-06 to 50,000 cup; that's about 60,000 psi. Winchester pressure systems showed their 308 ammo peaked at 52,000 cup which with transducer systems is 62,000 psi. You got the systems mixed up due to so many outfits dubbing copper crusher numbers as pounds per square inch.

I see what you mean but remember all barrels whip-a lot- but the idea is that all shots leave the barrel at precisely at the same point in the whip "curve" if you will. As long as that's consistent you'll get good accuracy .

If bullets leave on the muzzle axis upswing at the right place, slower ones will depart at a higher angle to compensate for their greater drop down range compared to the faster ones leaving sooner at a lower angle. This makes for better accuracy at longer ranges than medium ranges.

 

[Art Eatman]

Haven't seen videos.

So I'm back to my earlier comment about stiffness of a shorter receiver? The stiffness of anything to resist bending varies with length.

If the twist is uniform, shot to shot, does it matter?

As I've said before, I'm primarily a hunter, not a target shooter. Once I've made a rifle reliably sub-MOA, I sorta quit thinking about other factors. My '06 goal has been that any critter inside of 500 yards belongs to me.

Edit add: Back in the 1960s, the gun companies gave free "place mats" to gun stores. They had a thin rubber pad, as a protection for glass-top counters. The plastic surface was imprinted with cartridge data. Bullet, muzzle velocity and chamber pressure in psi. That's the source of my comment about 50,000 and 55,000. I took it for granted that the factories knew what the pressures were. All data for velocity, back then, was based on 26" barrels.

 

[Bart B.]

So I'm back to my earlier comment about stiffness of a shorter receiver? The stiffness of anything to resist bending varies with length. If the twist is uniform, shot to shot, does it matter?

As firearm accuracy/precision is best when all variables are uniform, yes, when all things are repeatable, it doesn't matter how much they wiggle, twist or shift.

Receiver cross section areas and shapes also matter for receivers of the same length.

The problems with round Remington receivers was mitigated when they were finally glued in flat bottom/side aluminum sleeves.

 

[Art Eatman]

Glued sleeves? Heh. The empiricist in me sez that if it works, it's good.

 

[Bart B.]

Example of sleeves:

http://bulletin.accurateshooter.com/2008/06/quality-action-sleeves-from-john-loh/

 

[salt&battery]

Art,

Barrels twist from bullets pushing against the rifling lands as they accelerate through the barrel. I and others can see scope reticles twist left shooting 308 Win and bigger ammo by keeping our aiming eye open looking at the outside edge of a reticle when firing.

As barrels whip vertically when fired because their bore and therefore recoil thrust axis is above the rifle's center of mass. They're screwed into receivers and therefore bend receivers in the same axis. Sometimes, barrel muzzle axis swings up to over 1 degree before the bullets leave the barrel.

And the more the butt plate contact point to your shoulder is below bore axis is, the more the whole rifle rises

That in turn also bends the scope mounted on the receiver.

Wood and plastic stocks bend too.

It all happens before the bullet leaves the barrel. The twist is small; a few degrees. Right hand twists keep right hand threaded barrel shanks tight against receivers.

Have you seen any of the videos showing this happening?

http://www.varmintal.com/aeste.htm

amazing stuff Bart I knew that happened but with modern equipment really amazing. years ago the Browning BOSS did the same thing it worked very well but the "purists" didn't like it. they found it out by accident getting BAR's back cause of accuracy so they cut a little off the barrel and made them better . so the figured the BOSS would adjust the whip to the load and it did work

 

[salt&battery]

Here's what can be done with a 308 shooting 155's at 800 yards:

View attachment 234979
Not so Art.

Arsenals and commercial plants loaded the 30-06 to 50,000 cup; that's about 60,000 psi. Winchester pressure systems showed their 308 ammo peaked at 52,000 cup which with transducer systems is 62,000 psi. You got the systems mixed up due to so many outfits dubbing copper crusher numbers as pounds per square inch.

If bullets leave on the muzzle axis upswing at the right place, slower ones will depart at a higher angle to compensate for their greater drop down range compared to the faster ones leaving sooner at a lower angle. This makes for better accuracy at longer ranges than medium ranges.

come on Bart you cant do that with those bullets and a 308. you need a 338 Lapua. that is amazing shooting and I don't doubt you did it with iron site palma rifle

 

[Bart B.]

they found it out by accident getting BAR's back cause of accuracy so they cut a little off the barrel and made them better . so they figured the BOSS would adjust the whip to the load and it did work

True, but few folks understand the physics as to why. Nor why Browning doesn't explain it correctly.

Browning claims adjusting Bosses makes bullets leave when the barrel is motionless for best accuracy. Problem with that is, slower bullets will leave on the downswing when at the top of its whip swing. Faster bullets the reverse at the bottom.

Only when all bullets leave on the muzzle axis upswing are both fast and slow ones are correctly compensated for. All bullets slower than average must leave at higher angles above the LOS, faster ones at lower angles. This seems to be hard for most folks to understand.

All bullets don't have the same barrel time for a given muzzle velocities. And barrels are in motion vibrating at several different harmonic frequencies above their resonant one until after bullets leave

come on Bart you cant do that with those bullets and a 308. you need a 338 Lapua. that is amazing shooting and I don't doubt you did it with iron site palma rifle

That was In 1993 testing a new barrel. I can't remember it I shot from prone with a scope in an F class setup or with no sights at all and a barrel 799 yards long. Bullets were from the first lot of 155's Sierra made. Shot the high aggregate score over 4 days in the first long range matches they were used in a few years earlier

 

[Bart B.]

Art, where did you get the idea that "velocity data back then" (1960's) was based on 26" barrels?

I've ever heard of that. No service rifles had them and very few commercial rifles did.

 

[Goosey]

Art, where did you get the idea that "velocity data back then" was based on 26" barrels?

I've ever heard of that.

I noticed the same thing in Phil Sharpe's The Rifle in America. The book had tables at the back and the ballistics of many cartridges were listed from 26" barrels (in some cases, the same figures are given today from 24" barrels). Probably unrelated, as 26" was the standard length of the Model 1886, but I also noticed the same in a 19th century Winchester catalog.

Looking it up I found this just now, Field & Stream, February 1975:

 

[Bart B.]

Most of the commercial factory reps at the Nationals I've asked about this velocity issue said they used SAAMI spec barrel lengths. Barrels were fixed in hard mounted universal receivers and they didn't recoil so velocity numbers reflected the ammo data accurately. It's normal they'll shoot bullets faster and have lower extreme spreads and standard deviations than hand held rifles will. It's bad juju to test ammo for ballistics and other way. Accuracy tests were made with regular commercial rifles.

The others were marketing types ignorant of ballistic details.

Lake City arsenal told me in the late 1960's they use 22" ballistic test barrels for 7.62, 24" for 30-06. Both from fixed barrels. Accuracy tests were made with heavy match grade 22" barrels laying in a Mann rest's V block. 24" ones for 30-06. Both fitted to M1903 or Remington 700 actions. Remington was operating that Army ammo plant then.

Arsenal accuracy specs for both were 270 shots at 600 yards. 3.5" mean radius (about 17" extreme spread) and for ball ammo 7.5" mean radius (about 30" extreme spread).

 

[jim in Anchorage]

.30-06 vs .308

I guess I fail to see the Vs in this? What one need ask themselves is what does the .308 Winchester offer over and above the 30-06 Springfield and what do I want a cartridge to do? Will the .308 Winchester meet my expectations or should I opt, in my situation, for the 30-06 Springfield. Looking at both cartridges what will the 30-06 give me the 308 won't and do I need that? Make a decision and move on the decision. Really it does not get any simpler. There is no versus anything as any person with a shooting interest should be able to read and interpret ballistic data.

Ron

They won't let me use a title that long.

 

[lysanderxiii]

Lake City arsenal told me in the late 1960's they use 22" ballistic test barrels for 7.62, 24" for 30-06; both from fixed barrels. Accuracy tests were made with heavy match grade 22" barrels laying in a Mann rest's V block. 24" ones for 30-06; fitted to M1903 or Remington 700 actions. Remington was operating that Army ammo plant then.

Not surprising, M1s, M1903s and M1919s had 24 inch barrels, M14s and M60s had 22 inch barrels. They wanted the factory velocity tests figures to match the expected service performance.

And, 5.56mm was tested in a 20 inch barrel....

 

[old heeler]

Lyman reloading manual # 45 use 26" barrel for 30-06 and 308 and only different was barrel twist. It's was around the 165gr that the 30-06 started getting more velocity. They stop loading data @ 200gr for the 308 and 220gr for the 30-06.

Berger manual used 26" barrel for 30-06 and 24" for 308.

Sierra used 26" with 1/10 twist for 30-06 and 308 and you can see over 200fps gain with 200gr Sierra bullet over the 308 and it's about same with 190gr,175gr,168 and it get less when using 165gr,150gr. Sierra didn't test any 220gr in 308 but did in 30-06.

I live hunt Co and I know few that use 308 but I know more that hunt with long action rifle.

 

[Art Eatman]

Bart, the gun store pads said 26". McBride's in Austin had them, from Remington and Winchester. I vaguely recall them from other gun shops.

 

[Bart B.]

Art, some rifle companies have put out incorrect info for decades.

Winchester for many years, claimed in print that fluted barrels are stiffer than standard ones of the same profile. Physically impossible because several long strips of metal were removed that, when still part of the barrel, helped resist barrels bending

Now Winchester says their hammer forged barrels are stress relieved and won't bend as they heat up in rapid fire. And their receiver face allows a perfect barrel fit. Yet they're 1 inch 100 yard accuracy guarantee is limited to 3 shots (with match grade ammo). Proof to me those barrels will bend as they heat up. If all was done as stated, they would shoot many rapid fire shots shots (10 per minute rate) in an inch at 100.

Regarding velocity tests. . . Only when both shooting systems's components are identical in all respects except test barrel chamber, cartridge case and powder charge weights to produce a given peak pressure, is comparing a given bullet's muzzle velocity in each system a valid one.

 

[Bart B.]

https://thefiringline.com/forums/attachment.php?attachmentid=39835&d=1229900860

Good info on 7.62 and 308 ammo.

 

[Clark]

In 2005, I bought an old M70 30-06 from some guy, who's uncle had just died in Alaska

The previous owner shot:
2 grizzlies
6 moose
10 mountain goats
6 sheep
109 Sitka Black tailed deer
16 black bear
2 caribou

-----------------

Then I rebarreled to 270, re stocked, and re scoped
I have shot 9 mule deer with it.
4 in 2008 and 5 in 2009.

 

[old heeler]

Since Bart hasn't and I will post rifle used Palma match which may be something like Bart shot.

http://www.6mmbr.com/gunweek059.html

you can walk in and buy rifle like that

 

[salt&battery]

Since Bart hasn't and I will post rifle used Palma match which may be something like Bart shot.

http://www.6mmbr.com/gunweek059.html

you can walk in and buy rifle like that

we are gonna need a bigger bank account lol

 

[Bobson]

I own neither but have owned a 30-06. These days, I'd personally opt for .308 and am hoping to buy one late this year, but I'm really not a big hunter. For me it's mostly an interest in military-type firearms. While I know 308 is far from being the best target round ballistically, and the military is only still using it because it wouldn't be realistically cost effective or feasible to switch all their firearms to something better (etc etc), that's still a good enough reason, to me, that I'd like to own the same thing for myself.

I'm under no false belief that it's the best at anything, but it's certainly not ineffective either. More than sufficient for my personal intentions and the ranges I find here in a Western WA, if I did need to use it for hunting. That said, I have a 30-30 in the safe for that specific purpose, should I ever actually make it out and hunt some blacktail or black bear out here.

 

[Clark]

I have been following Bart's great marksmanship with a 308 since May 1997 issue of Precision shooting. This month is the 20th anniversary.
It is important to remember the difference between a guy like me and a guy like Bart or David Tubb.
Those guys can lob in a heavy bullet with lots of trajectory.
Those guys can take recoil the same way with every shot.
Those guys are sick of wearing out barrels so they avoid easy to shoot but over bore cartridges.

So some putz like me that lacks recoil and trajectory skill, and never shoots out a barrel, is better off with a light bullet in an overbore cartridge.
140 gr in 7mmRemMag, 120 gr is 6.5-06, ... that would be poison to Bart or David, but it works for me and my little hunting trips.

 

[cdb1]

I have been following Bart's great marksmanship with a 308 since May 1997 issue of Precision shooting. This month is the 20th anniversary.
It is important to remember the difference between a guy like me and a guy like Bart or David Tubb.
Those guys can lob in a heavy bullet with lots of trajectory.
Those guys can take recoil the same way with every shot.
Those guys are sick of wearing out barrels so they avoid easy to shoot but over bore cartridges.

So some putz like me that lacks recoil and trajectory skill, and never shoots out a barrel, is better off with a light bullet in an overbore cartridge.
140 gr in 7mmRemMag, 120 gr is 6.5-06, ... that would be poison to Bart or David, but it works for me and my little hunting trips.

Bravo!

 

[salt&battery]

I have been following Bart's great marksmanship with a 308 since May 1997 issue of Precision shooting. This month is the 20th anniversary.
It is important to remember the difference between a guy like me and a guy like Bart or David Tubb.
Those guys can lob in a heavy bullet with lots of trajectory.
Those guys can take recoil the same way with every shot.
Those guys are sick of wearing out barrels so they avoid easy to shoot but over bore cartridges.

So some putz like me that lacks recoil and trajectory skill, and never shoots out a barrel, is better off with a light bullet in an overbore cartridge.
140 gr in 7mmRemMag, 120 gr is 6.5-06, ... that would be poison to Bart or David, but it works for me and my little hunting trips.

yes Bart is an excellent marksman and knows the science behind the ballistics. he is a walking encyclopedia on the subject

 

[Bart B.]

Thanks for the accolades but there are things I've not figured out. Doping the wind incorrectly has cost me more points on the scoreboards then all other things combined. And my scores shot offhand (standing) have been dubbed by trap and skeet experts as expanded cylinder bore.