How did the 168 grain .308 come about?

[SquirrelNuts]

I buy mostly 150 grain bullets of various styles and manufacturers to load for .30-06. I see a lot of different 150 grain, 165 grain, and 180 grain .308 bullets on the market. Most of the 168 grain bullets are designated as match. How did the weight of 168 grains come about such that they are the most accurate? Why would they be that much different than say 165 grain bullets?

 

[Jim Watson]

I figure that they fiddled with the design until they had some accurate bullets and then weighed one and it came out 168 grains. There is nothing magic about the weight, there are a lot of other good bullets that might puzzle you by not coming out as a multiple of 5 or 10. Why does a common .224" match bullet weigh 52 grains? Because it shoots accurately.

 

[depoloni]

Consider this "think so" hearsay...

Was the 168-grain match 308 bullet not developed by the military as a "scaled down" 50-caliber ball bullet that was so accurate? I believe the 69-grain match 224-cal bullet was yet again another scaled-down version of the 168-grain 308 bullet. I hope (know...) other more educated fellows-of-THR will straighten me out one way or another, but I don't believe it was "completely" random

 

[SquirrelNuts]

I am with you in that I seriously doubt it was a random selection. I bet there is a story that goes along with it. I am curious to know the story.

 

[loadedround]

I'm just going to repeat what I've been told my some knowledgeable shooters regarding the 168 gr bullet. This bullet weight and style was developed by the Army Marksmanship Unit(AMU) for long range competitive shooting at 600+ yds. The bullet design and weight was much better at bucking crosswinds than th old style 150 gr BT spitzer in use then. Again, just repeating what I was told by some old time competitors.

 

[catspaw]

I may be wrong, but I think Sierra developed the 168 for international competition. At one time it was called the "International" and used for 300 meter shooting. We all lucked out that it flies true out to 600 yards a beyond.

 

[Slamfire]

I may be wrong, but I think Sierra developed the 168 for international competition. At one time it was called the "International" and used for 300 meter shooting. We all lucked out that it flies true out to 600 yards a beyond

That's what I heard, but I did not hear who made it. Could have been a European bullet. A 1965 American rifleman article shows Sierra and Hornady 168's at Camp Perry.

There was a 180 grain Match Sierra, but for years the 168 was the "standard bullet" in a M1a out to 600 yards. (Yes I know some guys shot 190's!). The 175 SMK came in just as M1a's became a novelty on the firing line.

 

[Howard Roark]

Mid Tompkins developed the 168 for 300 meter CISM matches when he was in the USAMU.

 

[Bart B.]

Having met and chatted with the folks and shot many matches with one at Sierra Bullets who invented, produced and made famous, their 30 caliber 268-gr. match bullet, here's how it came about.

Sierra's 180- and 200-gr. spitzer boattail hunting bullets were probably the most accurate 30 caliber bullets on earth in the early 1950's. Used by many high power match rifle competitors, they did well indeed. Sierra soon came out with two full metal jacket versions which shot better than these hunting bullets. But the recoil with even the 180-gr. bullet was too much for accurate shooting from standing using a 14-pound free rifle in international 300 meter matches. In 1958, Sierra introduced their 168-gr. International bullet for use in free rifles and it was used by the match winner in the Olympics. A 150-gr. match bullet was also introduced at the same time, but it never caught on with competitors.

High power competitors soon began using it as well as the heavier 190-gr. one. It was used to win some benchrest matches, too.

Why that weight instead of 165 or 170 and why a hollow point? Martin Hull, Sierra's ballistic tech who tested all their bullets for accuracy when not out shooting matches with them told me it was what their best groups had when the lead core size/weight made finished bullet shoot the most accurate. The engineer who designed it told me it's shape and weight produced excellent compromises for ballistic coefficient, light recoil, super accuracy and dimensional uniformity. Especially at the body-boattail junction where FMJ bullet jackets don't form as uniformly at this point. It's shorter length compared to their 190-gr. bullet made jacket wall thickness uniformity much easier to attain. Jackets are made by the coin, cup, draw and trim process which requires extremely uniform material to end up with the jacket walls being exactly the same thickness all the way around for perfect balance. Well, maybe to a couple ten-thousandths of an inch tolerance instead of perfect.

In one of my tours through Sierra's California plant, Martin Hull showed me a batch of 100 yard test targets from a recent lot of 168's shot from their .308 Win. test barrel. A dozen or so 10-shot groups ranged from under 1/10th inch to not quite 2/10th inch. He asked me if I wanted a thousand of 'em and I said yes indeed. So I bought a plain brown box of 1000 unpolished bullets with the sizing lanolin still on them. He said those were much better than their standard accuracy specs for 168's which is 1/4th inch average and nothing bigger than 3/10th inch.

There's several busted myths out there regarding these bullets:

The US military folks did not design this bullet to buck the wind better than their 150-gr. bullet in ball ammo. The military M2 172-gr. FMJ boattail bullet developed in the 1920's has a much higher ballistic coefficient than Sierra's 168.

Its shape is not the "perfect" design for 30 caliber barrels. Depending on what ones objective is for 30 caliber bullets, any one of many shapes will be the best.

The hollow point was not designed to put a "perfect air point" at its front. Hollow point bullet jackets form more uniformly at their boattail than full metal jacket ones.

Their actual diameter of about .3082-inch will not cause case- or barrel-bursting pressures in a .3080-inch groove barrel. Barrels as tight in the groove as .3065-inch have shot them quite safely with max loads.

 

[Bart B.]

SquirrelNuts, any bullet weight can be made to extremly uniform weight and dimensional tolerances. But those with longer jackets hence longer bullets are harder to make very uniform. Lighter weight bullets are typically more uniform than heavier ones.

A given weight that's not an increment of 5 or 10 grains is wierd, but whatever the design team feels best for all the compromises they have to make is fine with me.

 

[Bart B.]

Howard Roark, Mid Tompkins never served one minute in the US Army. He was in the US Air Force stationed at Lackland Air Force Base in Texas assigned to their Rifle Team. I've known him since the mid 1960's. The design and introduction for Sierra's 30 caliber 168 International started before he joined the Air Force in 1960.

 

[Jim Watson]

a plain brown box of 1000 unpolished bullets

Warren Page said he got better than usual accuracy with unpolished benchrest bullets, too. But our products have to be pretty, don'cha know?

 

[Howard Roark]

Bart B, I stand corrected. I was thinking of Lones Wigger. I shot with Mids daughter last weekend and had Tompkins on the mind. Nancy is doing well and is back shooting.

 

[Bart B.]

Jim Watson:

Warren Page said he got better than usual accuracy with unpolished benchrest bullets, too. But our products have to be pretty, don'cha know?

Mr. Page probably did. Most stoolshooters I know who made their own bullets on Don Rorschach's famous dies never polished them. No need to as they weren't intended to win beauty contests.

Back in the 1960's, Sierra Bullet's Martin Hull kept a close eye on their 30 caliber Match Kings during production run starts. He would grab 10 as they came out of the pointing machine whose die formed the ogive on them. He'd seat 'em in 10 full length sized primed and charged cases then shoot 'em in their rail guns at 100 yards. Should the pointing machine start putting out bullets that shot in the ones (under 2/10ths inch) at 100 yards, he would move the tub catching them out and put another in its place. As long as those bullets kept shooting in the ones (sometimes in the zeros) he kept that tub there. Some of these super-accurate bullets would be set aside to check accuracy of their new test barrels; they were called "standards" or the benchmark of accuracy. If the bullets started shooting up in the twos, he put the old tub back then removed the top several inches of bullets from the "ones" tub and put 'em back in the regular one.

Regular tub bullets would be moved to their rubber lined cement mixers filled with wood chips to polish off the sizing lanolin and make those bullet jackets shine like the sun. Which made it easy for the inspectors to see jacket folds and other flaws that either didn't look good or might impair accuracy. These are the ones that got packed 100 to a green box and shipped out to retailers.

Those greasy, ugly bullets that shot so very well were packaged in plain brown boxes of 1000 except for the 200 grain HPMK's that had 900 per box. These were delivered to Mid Tompkins or Bob Jensen who took them to high power rifle matches around the country and sold them to competitors at about 10% lower than retail for the green boxes of 'em. Through 1000 yards, they shot about 30 to 40 percent better than the ones sold in green boxes of 100. One or two from a box might have a defect and would be trashed so folks who used them did the inspecting.

Sierra quit selling these ugly, greasy bullets in the late 1980's when Martin Hull retired. Too bad, as they won so many matches and set so many records. Nowadays, you may get several boxes of bullets that are unbelievably accurate and the rest will just be excellent or marvelous. Martin Hull told me the main reason the "standards" were as accurate as they were was due to superior jacket material being extremely homogenous in metalurgy and making jackets with really good copper resulted in near zero jacket wall tolerances.

I've got several thousand (168's, 180's and 190's) in the basement and am selling them as I only plan on using 155's from now on.

 

[Bart B.]

Howard Roark, Lones may well have been used as a "test bed" for the 168's. I've known him for years and shoot a lot of smallbore matches with him. Sierra's sent several prototypes to the USAMTU in Georgia for testing. They sent some prototype 6.5mm 140-gr. HPMK's to them and also to me through the USN Small Arms Match Conditioning Unit in the late '60 to test. We couldn't get 'em to shoot worth a hoot. Sierra told us they couldn't shoot 'em very accurate either. Jackets from material available couldn't be made good enough. Same problem with their 7mm 168 HPMK's. It was years before copper mills could make jacket material good enough for long, heavy match bullets.

 

[Howard Roark]

Sierra still uses brown boxes for experimental bullets. A few high power shooters around the country got the new Sierra 2156 bullets to test before they were rolled out for mass consumption. The AMU was instrumental in getting Sierra to start pointing these bullets. They shoot good but could do a better job with the pointing.

 

[Bart B.]

Howard, in early 1991, Mid asked me to help develop a load for Sierra's first Palma bullet. I got two 1K round brown boxes of those ugly slippery bullets. Several of us metered different powders/charges with 210M primers and new cases weighing about 170 grains. We tested 'em at 1000 yards.

Some loads shot pretty good, a few were pretty bad, but 45.3 grains of IMR4895 seemed best for accuracy. Load having the most uniform charge weight, pressure and velocity used AA2520 ball powder. It was also the least accurate.

Loaded on two Dillon 1050 progressives, some lots of primers produced better accuracy than others but most were very good. 20 rounds were picked at random and shot into 2.7 inches at 600 yards from Bob Jensen's Palma rifle. Not too shabby for new cases with a 3/10ths grain charge weight spread and 3/1000ths max bullet runout.

When first used at the 1991 Rocky Mountain Palma Matches' International Division, several teams from around the world came to test these new bullets. Everyone was duly impressed. None of the Brits, New Zelanders, Afrikaners nor Aussies had ever shot bullets that accurate as they had to use military arsenal ammo/bullets in their fullbore matches. Most agreed this ammo would easily shoot 4 inches at 600 yards and often better. This new bullet soon became the world standard for long range matches.

 

[USSR]

A note about the Sierra 168gr MatchKing bullet: It was designed for 300 meter competition, as previously noted, and as such, it is not a LR bullet. The boattail angle is all wrong for LR shooting. Sierra designed a new bullet for that purpose (175gr MatchKing) which duplicates the 9 degree boattail as used on the USGI 174gr FMJBT match bullet.

Don

 

[Bart B.]

USSR, wasn't Sierra's 180 (FMJ, plus short and long boattail versions), 190, 200 (FMJ and HP versions), 220, 240 and 250 grain 30 caliber MK's with a long 9 degree boattail all designed for long range shooting, too? Their 190 was probably the most popular of all for ranges 600 yards and greater.

These came out long before their 175 HPMK did.

 

[rcmodel]

The Army first used the 172 grain BT in Palma Match ammo in 1925.

Wonder if the 168 didn't just evolve from that?

rc

 

[~z]

A very interesting read, my thanks to everyone involved.
Side note: Bart, you say you have several thousand (168's, 180's and 190's) in the basement and am selling them. Beyond all the info, THAT caught my attention. Please PM or otherwise supply details, I may be willing to take some off your hands.
Thanks,
~z

 

[Slamfire]

The Army first used the 172 grain BT in Palma Match ammo in 1925.

Wonder if the 168 didn't just evolve from that?

There is very little that is totally new or was not influenced by something else. In target shooting, reducing recoil without trading off accuracy or ballistic ability would have been a primary consideration. I cannot imagine shooting a 180 grain bullet offhand. If you ever shot on the 300 meter target, the slightest blink or flinch and you are way out of the center.

 

[Jim Watson]

Old data for the 300 metre load was the 173 gr military match bullet or a 180 grain commercial boattail and a mild load of HiVel #2 for 2200-2300 fps. Not much more than .30-30 recoil and in a heavy free rifle. Not like shooting M1 ball.

 

[USSR]

USSR, wasn't Sierra's 180 (FMJ, plus short and long boattail versions), 190, 200 (FMJ and HP versions), 220, 240 and 250 grain 30 caliber MK's with a long 9 degree boattail all designed for long range shooting, too? Their 190 was probably the most popular of all for ranges 600 yards and greater.

These came out long before their 175 HPMK did.

Bart,

Yes, they all came out prior to the 175SMK. I was referring more to the bullets used in USGI ammo (168SMK in M852 and 174 FMJBT in M118). And, yes, the 190SMK is a great bullet.

Don

 

[Bart B.]

SlamFire1 states:

There is very little that is totally new or was not influenced by something else. In target shooting, reducing recoil without trading off accuracy or ballistic ability would have been a primary consideration. I cannot imagine shooting a 180 grain bullet offhand. If you ever shot on the 300 meter target, the slightest blink or flinch and you are way out of the center.

Good reasoning. Very true.

My friend Lones Wigger decided to ignore all this when he chose the .30-06 cartridge with 200 grain Sierra's for a 300 metre free rifle match in the Olympics years ago. He knew the wind would be an issue and was willing to give up a bit of accuracy for much better wind bucking those heavy bullets had. He won the match and took the gold. The Remington 700 based rifle he used is still on display at the US Olympic Center in Colorado Springs.