Intrinsic Accuracy of the .308 round.

[amlevin]

What is considered to be the intrinsic accuracy of the .308 win cartridge? If every possible variable was controlled from case volume, powder burn, bullet release, barrel friction, barrel harmonics, etc, what is the "BEST" one could expect from let's say a 175 gr .308 bullet?

At what point does one have to put more effort into gaining accuracy with the .308 than they can get out of it?

 

[bheadboy]

in the mid 1970's Wally Hart won heavy var. Br match with a 308, best group of his was in the .100 range and possibly below .100, I can't remember.

The 308 will do the job.

Bob

 

[Turbulent Turtle]

I actually do not understand the premise of your question, amlevin. So help me out here, what are you trying to do, at what distance and under what circumstances?

There are so many variables it's difficult to put together any type of decent response.

If you are asking about 1000 yard competitions, I will be the first to tell you there are better cartridges for that task. If you are talking 100 yard BR, the same answer applies, but these would be very different cartridges than in the first instance.

I will also say that it depends on the bullet and the 175SMK you mention is simply not the best for the .308 under any scenario with the exception that it's the only one you have access to or your other options are worse bullets.

 

[PRECISIONWELDING01]

155 grain Sierra Palma bullet and 185 grain juggernauts will be better bullets in the 308 have won more matches at 1000 then 175.the 308 is inherently accurate it is your job to read the wind that is where the fun begins

 

[XTR]

... it is your job to read the wind that is where the fun begins

What do you mean Thomas? You mean I can't load the same bullets, brass, reloading technique, bipod, and scope that Nic Taylor used to win at Raton and shoot High master scores at 1000 yards? What do I need to get the same rear bag too? ;D

 

[mysticplayer]

I am happy with 1/3min accuracy at 300m with very low vertical in my FTR rifles.

It translates to hitting the X ring IF, I can figure out the wind at 1000yds

Jerry

 

[broncman]

I pulled targets for one of the National FTR guys at a match in Oak Ridge earlier this year...twenty shot I could cover with my hand....if it had been centered it would have been a perfect score. Dropped only one or two points. Accuracy is not the issue..

 

[Turbulent Turtle]

I pulled targets for one of the National FTR guys at a match in Oak Ridge earlier this year...twenty shot I could cover with my hand....if it had been centered it would have been a perfect score. Dropped only one or two points. Accuracy is not the issue..

Well, I would say that PRECISION is not the issue, accuracy is.

 

[broncman]

Touche'.....
The accurate but not precise, precise but not accurate scenario.

One without the other is still dropped points

 

[stool]

what the heck are you talking about ??
it is not just the cartridge, but the gun and the shooter also.
what games are you playing ...palma ftr 1000yd what.....
those game are shot with the 308( well 7.62x51 actually) because it is the rule

no one shoots 308 win at 1000yds by choice...cause lots are better at 1000yds.

intrinsic.....lol

What is considered to be the intrinsic accuracy of the .308 win cartridge? If every possible variable was controlled from case volume, powder burn, bullet release, barrel friction, barrel harmonics, etc, what is the "BEST" one could expect from let's say a 175 gr .308 bullet?

At what point does one have to put more effort into gaining accuracy with the .308 than they can get out of it?

 

[XTR]

Stool, your point is "precise"; however, I'd say that it may not be accurate

A whole lot of us choose to shoot the 308 at 1000 as evidenced by the popularity of Palma and F-TR. Every one of us in F-TR or shooting Palma could be shooting F-Open or shooting "Any" HP competitions yet we choose not to do so.

F-TR and Palma exist because they are popular and we enjoy the format if the competition. Certainly if I had to pick a caliber for 1000 yard shooting in an unlimited format I'd use something else, but I would hate to go that route. I like the "match racing" format of F-TR, and as such I choose the 308.

 

[stool]

yes i should have worded it diff....
most people shooting 1000yd br do not shoot 308 win

 

[stinnett1981]

What is considered to be the intrinsic accuracy of the .308 win cartridge? If every possible variable was controlled from case volume, powder burn, bullet release, barrel friction, barrel harmonics, etc, what is the "BEST" one could expect from let's say a 175 gr .308 bullet?

At what point does one have to put more effort into gaining accuracy with the .308 than they can get out of it?

Are you simply asking how accurate a .308win is or can be? I never shot one before until a few months ago. Its a very popular cartridge and I always heard they are very accurate so I decided to have one built. I received it a couple months ago. Im impressed with the .308win. I have about 180 rounds down the barrel and I only worked up 1 load for it so far. Im shooting the 175 grain Sierra Matchkings with Varget powder. It shoots 5 shot groups in 1 hole at 100 yards and .75moa and sometimes better out to 500 yards. I havent had the chance to go past that yet. Hopefully the weather will warm up a tad one of these weekends so I can see what it will do out to 1000 yards. Here is a few pics of some 100 yard groups after I figured out my load. Like the others said. What is your plans or game? Why do you ask?

 

[Bart B.]

Starting back in the mid 1960's when the .308 Win. was first used in NRA high power match rifle competition, I've shot many matches with the folks who made it replace the .30-06 as "the" cartridge for use through 600 yards. Proper tests with Win. 70 based match rifles epoxy bedded in wood stocks clamped in free-recoil machine rests proved its prowess in the accuracy game with shoulder fired rifles fired at bullseye targets. Its accuracy was the reason the NRA in 1966 had to reduce the scoring ring sizes of high power targets to reduce the number of unbreakable ties shot with the .308. It's accuracy was half to two-thirds what the .30-06 chambered rifles would produce with equal quality components and barrels.

The best of these rifles with Sierra's or Lapua's bullets, WCC58, WCC60 or WW cases and IMR4064 would shoot under 1/4 MOA at 200 yards and 1/3 MOA at 300, 190's and 200's under 1/2 MOA at 600 and under 3/4 MOA at 1000. That's as good as benchrest rifles shot at those ranges these days shoot if you use extreme spread of a few dozen shots fired. One test in 1971 with Lapua D46 FMJRB 185-gr. match bullets produced several 10-shot groups at 600 yards ranging from about .7 inch up to 1.5 inch; one at about .9 inch was pictured in a 1971 American Rifleman Magazine with a Lapua bullet ad. Then a 40-shot group with them was fired starting with a cold barrel shooting once every 30 seconds or so; they all went into 1.92 inches on that 600 yard target. That rifle and that ammo won all the NRA 600-yard matches at the Nationals that year.

240 and 250 grain bullets from 1:8 twist 28" barrels shot from .308 cases will also shoot under 3/4 MOA at 1000. And they buck the wind quite well too. Recoil's their only thing that starts to make them harder to shoot accurately on paper.

In 1991, when Sierra's 155-gr. Palma bullet was first used in competition, folks loaded a few thousand prototype bullets atop 45.3 grains of IMR4895 metered (not weighed) in new Win. "PALMA 92" very uniform cases primed with Fed 210M's on two Dillon 1050 progressives. 20 rounds were picked at random for a test in a pre-'64 based Palma rifle clamped in a machine rest. All 20 bullets went into 2.7 inches at 600 yards and a picture of that group was published in a fall 1991 issue of Handloader magazine. Not too shabby for 3/10ths grain spread in charge weight, .004" max bullet runout and new cases in a virtual SAAMI spec chamber except for a shorter throat for those short bullets. A couple dozen top Palma competitors from around the world shooting it that year all said it easily shot about inches or better at 600 in their rifles with all sorts of bore, groove and chamber dimensions. Sierra's Palma bullet will shoot under 3/4 MOA at 1000 from a well built rifle properly tested; same thing with Berger's Palma bullets.

With the semiauto service rifles, the Navy's 7.62 NATO converted match grade A Garands would shoot good lots of M118 match ammo into about 2/3 MOA at 300 and 1 MOA at 600 yards. With good commercial match ammo, accuracy was better. It took the Army and Marine Corps teams a bit longer to get their M14NM's producing the accuracy of the Navy's M1's, but they did it, Handloads for these rifles shot darned near as accurate as they did in bolt guns and better than M118 7.62 Match ammo. Sierra's 168 replaced the 1920's match bullet of 172 grains for arsenal match ammo, the M852. It shot great through 600 yards but starting at 800 yards in cooler weither and half worn out barrels, it went subsonic. Lake City and Sierra Bullets contrived the 175-gr. HPMK with the longer boattail like their 190 has and long range accuracy got better.

Some military teams replaced the M118 bullet with the earlier Sierra 180 HPMK bullet with the long boattail and that may well have been the most accurate load ever shot through 1000 yards in M14NM service rifles. It was the equal of the USN and USAF long range loads for Garands with a primed M118 case stuffed with IMR4320 under a Sierra 190 grain HPMK.

It was the US Army International Shooters who spawned the need for a medium weight bullet for their .308 Win. free rifles used in 300 meter matches. Western Cartridge Company's 200 and 197 grain match bullets had too much recoil to shoot really well but their WCC58 and WCC60 cases have yet to be equalled for uniformity; Lapua's come pretty close, though. They got in cahoots with Sierra and the 168-gr HP International 30 caliber bullet was the result. Gary Anderson won his share of gold medals in international matches with that bullet as well as the Nationals; his 200-15X record at standing on the 200 yard line was the one to beat for decades.

The .308's as accurate a round as any of the others these days, but it doesn't quite buck the wind as good as others. Sierra Bullets tests virtually all their 30 caliber bullets 180-gr. and lighter in .308 Win barreled rail guns. I've seen a few series of their 10-shot groups testing HPMK's in production runs when they had their plant in California. Good batches of bullets shot in the ones; target after target after target at 100 yards. At their Missoury facility, good lots shoot 1/2 inch in their indoor range of 200 yards.

amlevin, with a well built rifle whose groove diameters are a few 10-thousandths smaller than the 175 HPMK bullets, proper handloads (full length sized cases without expander balls bending their necks), you can get the above levels of accuracy with them. Providing they're properly tested.

 

[stool]

very nice summary of the mil style life of the 7.62x51/308 win.
as far as those 185 gr lapua bullets....i just bought 2000, along with 2000 of their 155's in moly.....
i like 308'a and its russian cousin the 7.62x54/53r.

that 1991 palma article got me hooked on gas guns and 308

 

[Bart B.]

Stool, thanks for your comment on my post.

I was one of the former Palma Team members that helped work up that load for Sierra's 155's. We used new cases about 170-grains in weight, Fed 210M primers, several powders and the bullet seated to an OAL of 2.80". Six of us tested our loads with 20-shot groups at 1000 yards.

Several loads were sent to a lab for testing. Best muzzle velocity, peak pressure and powder charge weight uniformity was with AA2520 ball powder. It also produced the worst accuracy. Best accuracy was with IMR4895 but with average numbers for muzzle velocity, peak pressure and powder charge weight. The load used for the matches was 45.3 grains of it.

Winchester had to retool the production line 3 times to get uniformity of the cases to the specs we wanted; they were probably the most uniform cases made since the famous WCC58 and WCC60 match cases from the plant in Illion, IL.

Those Lapua 185's that shot so darned accurate were spun at 30,000 rpm testing them for balance. Those way unbalanced flew out of the collet chucked up in a Dremel Moto Tool and bounced off the walls. But a couple hundred out of several hundred tested were perfect.

 

[stool]

so i need to buy a dremel and mack a collet....

 

[oldroper]

Stool, thanks for your comment on my post.

I was one of the former Palma Team members that helped work up that load for Sierra's 155's. We used new cases about 170-grains in weight, Fed 210M primers, several powders and the bullet seated to an OAL of 2.80". Six of us tested our loads with 20-shot groups at 1000 yards.

Several loads were sent to a lab for testing. Best muzzle velocity, peak pressure and powder charge weight uniformity was with AA2520 ball powder. It also produced the worst accuracy. Best accuracy was with IMR4895 but with average numbers for muzzle velocity, peak pressure and powder charge weight. The load used for the matches was 45.3 grains of it.

Winchester had to retool the production line 3 times to get uniformity of the cases to the specs we wanted; they were probably the most uniform cases made since the famous WCC58 and WCC60 match cases from the plant in Illion, IL.

Those Lapua 185's that shot so darned accurate were spun at 30,000 rpm testing them for balance. Those way unbalanced flew out of the collet chucked up in a Dremel Moto Tool and bounced off the walls. But a couple hundred out of several hundred tested were perfect.

Bart B, this is one of you post on same subject from another forum


I was one of the Palma Team members that developed the load in early 1991 those Winchester cases were made for Sierra's prototype 155's they sent us to test with. We developed loads to test with cases weighing between 165 and 170 grains. I weighed about 50 random samples of the 92 PALMA ones I got from the first match that ammo was used in the summer of 1991. Weight spread was 1.5 grains; excellent by any means. Mid told me back in the early 1970's that a 1% spread in case weight's good enough. That's the only case "prep" he's ever done; no flash hole or pocket reaming. Sometimes he would turn necks if they had more than a .001" spread in wall thickness.

I bunked with Bob Jensen in South Africa in the late 1990's for their Nationals and we talked one night about those 92 PALMA headstamped cases. The Western Cartridge Company plant in Illinois had to try 3 or 4 sets of case forming dies for the coin, cup, draw, head and trim processes to make them from cartridge brass sheets. Those cases were a little better than the great WCC58 and WCC60 match cases made there for the US Olympic Free Rifle Team in those years. Having many hundreds of each and weighed some of them, they were 1.8 to 2.1 grains for spread.

In a phone chat with WCC's production engineer in 1991 about those cases, he said that someone had asked about using those old dies they still have stored away for the 92 PALMA run. But WCC denied as the WCC58's averaged 150 grains and the WCC60 156; too thin for safety in the 1990's 'cause so many people loaded ammo way too hot. Which is why the 92 PALMA ones averaged about 169 grains.

That ammo shot about 1/2 MOA at worst in several rifles from around the world in the first match it was used in; 1991 Rocky Mountain Palma Matches at the NRA range at the Whittington Center, Raton, NM. A year later at the 1992 World Palma Matches held there, top long range competitors from all over said it was the most accurate batch of ammo they had ever shot. At a dinner on night during that event with Bob, Mid and others, one conversation was about how so many folks waste lots of time measuring stuff that doesn't matter trying to get the best accuracy. Case weight spread of 1% is good enough.

This is little about Bob Jensen

Bob Jensen - Paradise Valley, ArizonaI think it's safe to say that Bob Jensen has loaded more .308 ammunition for Palma shooting than any other person I'm aware of. Bob, of course, loaded over 300,000 rounds for the 1992 Palma Match, ammunition that was used by competitors from all nations; and before that, he loaded 98,000 rounds for the US Army Marksmanship Unit.

I got the above from here also one of our posters

http://riflemansjournal.blogspot.com/2010/01/reloading-western-shooters-pet-loads.html

From my understand which you left out Bob Jensen tested 92 Palma ammo on a machine rest.

 

[Bart B.]

oldroper, I referred to Bob Jensen's machine rest tests of that '92 Palma ammo in his Win. 70 he and his two sons loaded at his Tucson, AZ, shop in mid 1991 in an earlier post in this thread with the following:

"20 rounds were picked at random for a test in a pre-'64 based Palma rifle clamped in a machine rest. All 20 bullets went into 2.7 inches at 600 yards and a picture of that group was published in a fall 1991 issue of Handloader magazine."

 

[broncman]

Would LOVE to hear more about the bullet spin test and collet!