308 question

[Ajtozzi]

Hi there!

I am a VERY casual 308 shooter. At this current point in my life I do not have the time to shoot as much as I'd like nor do I have time to tinker around with various loads. All I am looking for is a basic, safe, reliable recipe for loading 308.

My 308 rifle is a basic Howa 1500 bolt action.

I have on hand two pounds of Reloader 17, 1,000 Federal Large Magnum match grade primers and about 200 pieces of once fired (in my rifle) brass. I am looking to purchase 30 cal bullets and I have the following questions:

1) should I go with 110 grain plated round nose bullets or Hornady A-Max 168 grain match

2) can anyone recommend a safe, reliable recipe for either of the above bullets?

THANK YOU!

[hoodlum]

First off, I would ditch those federal magnum primers... Very soft and will cause over pressure very easily... Get standard large primers.... I got a box of the federal magnum primers when nothing else was available, dropped my normal loads by 10% and blew out 4 primers in the first 10 shots... I broke the rest down, and now have a box of 980 primers I refuse to use....
My Howa has a 1/12 twist and really loves 110gr sierra varminters , as well as 150gr match kings... It will shoot the 168's well too, but they will loose stability after 3 or 400 yrds due to the slow twist...
You didn't say what cases you have... The case capacity will have a large determining factor on powder charge.... Your question of what charge weight is one I wouldn't touch with a 10 ft pole.... I would hate to be responsible for destroying your rifle, or more importantly, yourself....
Hoodlum

[Ajtozzi]

Thanks Hoodlum

There are no ranges near me that are over 300 yards so anything past that I'm not too concerned about.

I will keep an eye out for regular large rifle primers then!! Seems like I have a box if magnums for sale....LOL

The cases I have are all Federal.

[William T. Watts]

(1) I've never had any problems with Federal primers period!! Their cup is the softest of the primers we have access to, of more concern to me your using the softest brass with the smallest capacity of any cases I know of. RL17 is a double base powder which often needs the hotter spark of a mag primer, start with the starting load and go up in .3 gr steps should produce a good load fairly quickly. Good luck! William

[Ajtozzi]

So I am not opposed to buying quality brass if necessary. My local store has Hornady brass in 308 for sale - is that much better quality than Federal?

William - so I should be OK with these primers? I was thinking about 44 grains to start with. How's that sound?

[jwrowland77]

Yes you should be perfectly good with those primers.

I use CCI Large Rifle Magnum, and have had 0 issues so far. Just start at the start load and work your way up, and you should have no issues with over-pressure.

[Ajtozzi]

So 168 grain bullets should be fine? I'm sorry for all the seemingly dumb questions but this is my first foray into rifle reloading.

[SSA]

If I had Reloader 17, Federal large magnum primers, Federal brass, and 168 gr AMAX bullets, I would load some up, starting with 46 grains of powder.

[Ajtozzi]

Thank you SSA

[William T. Watts]

Alliant website lists 50grs of RL17 as max with both the 150gr & 165gr Speer BT bullets with Federal 210 primers. Alliant is a slow powder for the .308 round and should be fool proof without a significant risk of a overcharge. SSA suggested 46gr charge for a starting load with your 168 gr projectile, I would reduce that to 45grs since your using mag primers and begin at that level. I would always er on the side of caution, this isn't a powder normally encountered in a 308 with very little load data available, your kind of flying by the seat of your pants on this one. Nothing is wrong with the federal cases except they are soft and do have a problem with the primer pockets opening up with near max charges. If the primer starts to need less effort to seat the primer fully in the primer pocket it's time to discard the cases. One last thought keep a close eye on the case length, use a good set of calipers to ensure the cases do not exceed max length, if the case mouth is forced in to the throat/leade the case cannot expand enough to release the bullet cleanly! Good luck!! William

[Ajtozzi]

Thanks William

[Bart B.]

hoodlum sez:

My Howa has a 1/12 twist and really loves 110gr sierra varminters , as well as 150gr match kings... It will shoot the 168's well too, but they will loose stability after 3 or 400 yrds due to the slow twist...

It's not the twist that causes the 168's to loose stability at the longer ranges. Many folks have shot 168's from 24" barrels in 7.62 NATO Garands with their 1:12 twist very accurate all the way to 1000 yards. I, for one, can attest to that as can many military rifle team members winning matches and setting records with 168's in both M1 and M14 rifles at 600 yards with their 1:12 twist barrels.

It's the muzzle velocity combined with the poor drag (BC) design of Sierra's 168. If they leave at least 2700 fps from a 1:12 twist barrel, they'll remain supersonic through 1000 yards in all but the coldest weather and shoot very accurate.

[Unclenick]

Ajtozzi,

You will find RL-17 too slow to burn efficiently or completely with light bullets like the 110's. You want something more like IMR3031 or H322 or even IMR4198 with those. RL-17 will work far better with the 168's, and is at its best with 175 and 180 grain bullets in the .308. But RL15, IMR4064, IMR4895, and Varget are used far more often in the .308 even with your bullet weight, so you are operating on the slow side of burn rates even for the 168.

The primers you have should be fine, but do work your loads up from the bottom load in increments of not over 2% of the maximum load, while watching out for pressure signs. Those Federal Magnum primers are known to be about the hottest primer on the market and you may end up with a charge that's several percent smaller than the maximum given for the 210M. That's not guaranteed, as it depends on a number of factors, but it's unlikely someone will have a tried-and-true recipe for you since neither magnum primers nor your powder are commonly used in .308, except that magnum primers are often used with the harder-to-light older spherical propellant formulations, like BL-C(2) or H380. But given that RL-17 is a little slow for the job, you might actually have a best case combination there, with the primer helping it light up slightly faster. Just work up in those steps. In the end you may find no problem getting to the top charge, but there's no way to know in advance.

RL-17 will tend to produce too much gas port pressure in an M1A or other gas-operated rifle, but will be fine in a bolt rifle with the heavier bullets.

On your brass, many folks have trouble with Federal's softness, while others have gotten long life from them. This article shows Federal and Remington and Norma using 80:20 copper:zinc (low brass, meaning low zinc content). which is softer than military 70:30 cartridge brass as used by Winchester and S&B. However, you only hear complaints about Federal's softness. This likely means they form their cases in fewer steps, as even low brass will harden with enough working. The folks who claim good life from Federal brass, when you analyze their loads, turn out to be running below 50,000 psi. So, Federal brass is fine for moderate loads. Unfortunately, Reloader 17 won't be happy running at modest pressures, and you'll do better with something like H4895 for those, as it doesn't mind running at somewhat reduced pressure.

Federal brass is a little heavy, but is not the heaviest commercial brass by any means. Among the brass I have, that honor goes to IMI Match .308 brass, which averages 186 grains per case in my lot. That's heavier than Lake City 7.62 brass, which runs 178—182 grains among the different lots I have. The Federal I have is old, and weighs about 172 grains, same as Lapua, which is a reloading favorite. Current lots may differ a bit. Old (15 yrs) Remington .308 brass I have runs about 168 grains, and some 10 year old Winchester I have (last lot of Winchester I bought) averages 156 grains. I don't have any Hornady, but understand it is light, like Winchester, so it should have Winchester-like case capacity. An old rule of thumb is .06 to .07 grains of powder reduction for every grain of added case weight to keep peak pressures the same. So nearly 2 grains less powder in an IMI .308 Win case than in a Winchester or Hornady .308 Win case.

12" twist is the SAAMI standard twist for .308 Win and should be close to ideal with the 168 grain A-max. The stability estimator on the JBM ballistics site gives it a gyroscopic stability factor of 1.587 at 2700 fps under ICAO standard atmospheric conditions. Various authorities put gyroscopic stability factors of anywhere from 1.4 to 1.7 as optimal for match accuracy, with 1.5 being the most common recommendation, so you should be right in the sweet spot range. Until they drop down into the transonic velocity range (950—1400 fps), where drag jumps up, bullets become more stable as they go down range, not less. So you won't see these tumble at 400 yards unless you load them to very low muzzle velocities. The 168 grain Sierra MatchKing HP Match bullet is famous for becoming unstable as it drops below 1400 fps (about 700 yards in a typical load from a 24" barrel), and Bryan Litz says that's partly the fault of the 13° boattail angle introducing a dynamic instability. I've experienced this twice with the Sierra bullet and assume its copies by Norma, Speer, and Hornady do the same thing. The 168 grain A-max also has that 13° boattail. I just don't know from personal experience about that particular bullet. But because the rate of spin (angular velocity) of a bullet slows more gradually than forward velocity does, its stability factor tends to get higher as it flies down range until that transonic velocity range is reached. So I don't expect the A-max to misbehave until then.

In your shoes, I would just be following the advice to start at 46 grains and work up. Even though 2% steps are safe for pressure, I work at 1% or less in order not to skip over an accuracy sweet spot along the way. You might be want to read through Dan Newberry's OCW method for an organized way to identify the most accurate load. Even though you need to fire three at each load level in his round robin, you can watch for pressure signs as you go up through the first rotation.

[Bart B.]

Ah yes, the 13 degree boattail connumdrum that plagued both the 168 Int'l bullet for long range competition back in 1958 when it came out. Same as Sierra's 180 HPMK when in the mid 1980's it's 9 degree boattail was changed to 13 degrees so the same base forming dies could be used for both weights. The new 180 also had stability degradation issues starting about 100 yards further down range than the 168's have. The original form was a well known match winner and record setter in long range matches when shot from the .308 case.

Lake City Army Ammo Plant got Sierra to make a 175-gr. HPMK bullet with a 9 degree boattail that solved the problems with the 180 and 168 HPMK's at long range.

[Sierra280]

^those 175gr SMK used in the m118lr ammo STAY STABLE at transonic speeds (I'd love to know how they discovered that). That being said, aren't the mil spec barrels 11.25 twist? The 175gr SMK'S seem to work fine with it.

[Jimro]

Yes, milspec barrels are 1:11.25 twist.

Jimro

[Bart B.]

Sierra280, I don't think anyone's claimed Sierra's 175's stay stable at transonic speeds. But they do stay supersonic past 1000 yards when fired in decent 22-inch and 24-inch long barrels as fired in M118 LR ammo. That's why their use in the M118LR round replaced the Sierra 168's use in M852 7.62 NATO match ammo.

Jimro and Sierra280, I'm not aware of any US arsenal made barrel for the 7.62 NATO round having anything but a 1:12 twist as stated in MIL SPECs. All the M14 and M1 barrels from the arsenal in Springfield, MA, I've measured had that twist rate. Besides, a bullet leaving a 1:12 twist barrel is spinning at a faster twist down range; its rpm rate doesn't slow down as much as its velocity through the air.

I've shot Sierra's 175's and their new 180's from a 1:13 twist .300 Win. Mag. barrel with excellent accuracy at 1000 yards.

[Sierra280]

Nobody here did mention the transonic stability, that is why I thought it was worth adding. Especially since unclenick mention how the 168gr SMK's lose stability at transonic speed (1400-1100fps). I got that info on the 175gr SMK's from Litz's last book, "accuracy and precision"

[Unclenick]

Yes. They simply copied the 9° boattail from the old 173 grain M1 bullet design. That had been worked out by empirical trial and error testing and worked so well the extreme range was over 5000 yards. It didn't become unstable and tumble or it wouldn't get that far. The 1373 yard sniper kill by Sgt. Gilliland would not have happened if his bullet didn't stay on course through the transonic range.

I believe the 11.25" twist is based on 285 mm or some other metric equivalent that is close to the 11" twist the marksmanship units preferred for match accurized M14's using 168 grain MatchKings. I can't say why it worked best. The general stability factor calculators show 12.5"-13" should be close to ideal for the 175 under ICAO standard metro conditions.

[Jeff2131]

I agree with "ditch the magnum primers". I wouldnt consider using a magnum until my bullet was over 180gr. I reload 150 & 180 gr seirra and hornady. Standard cci primers, imr4320 powder, and ive had nothing but fantastic results. Everytime i ask someone about using magnum primers they all tell me that unless it states it in the book, its not a good idea to use it.

[Bart B.]

There are some folks winning Palma matches shooting 155's from .308 cases primed with magnum primers. So, sometimes magnum primers do work very well indeed for even 45 grains of powder.

Regarding the military teams' using 1:11 twist barrels in their M14's, here's what I've gleaned from their team members decades ago..... While the spec for M14 barrels (service and NM ones put in TRW receivers) is 1:12, when Sierra's 180-gr HPMK was stuffed in a new M118 case after pulling its 172-gr. bullet, sometimes in cold weather those bullets started subsonic speeds close to 1000 yards shot from 1:12 twist barrels. Using a 1:11 twist barrel fixed the bullet starting to go unstable issue which was more of a concern than shooting 168's at 1000 yards.

This usually happened with barrels with a couple thousand rounds through them that had a bit slower muzzle velocity than a new barrel produced. So the 1:11 twist barrels had a longer life in all temperatures.

On the other hand, the USN and USAF M1 Garand arsenal 24" barrels in 7.62 NATO had 1:12 twists and rarely had the subsonic problems M14's did with 168's at 1000 using M852 ammo. Except in DCM/CMP matches at the Nationals, 168's were seldom used past 600 yards as Sierra 190's or Lapua 185's over 44 grains of IMR4320 outperformed anything else accuracy wise all the way to 1000 yards.

Also note that the bolt gunners shooting NRA match rifles chambered for the .308 oft times used reduced loads for 168's at 200 and 300 yards. A 1:11 twist in their 26: barrels helped much accuracy wise for that situation. It also helped folks get great accuracy with both 190 and 200 grain HPMK so that same barrel did great with a wide range of bullet weights shot at the right speed for best stabilization and accuracy. I can't help but think this partially influenced the military teams to use 1:11 twist barrels in their M14's.

[jwrowland77]

I have a pretty good load using magnum primers and 44.5 of IMR4895. Gets me dime sized groups anyway. Can't wait to get to the range next time to shoot a little further out.

[Unclenick]

Bart,

Thanks for the info on the heavier bullet history. That 11" twist's origin makes a lot more sense now. And, obviously, military weapons aren't always shooting in standard atmospheric conditions. They need some cold, dense air stability margin in a sniper system that a fair weather target shooter won't have.

[Bart B.]

Unclenick, I've shot Palma and long 1000 yard matches with temp's in the upper 20's. Didn't realize the thicker air required about 2 MOA more elevation on the sight compared to upper 80's until I fired my first sighters. Both instances were at 6600 feet altitude at the NRA Whittington Center.

I think benchresters add another click of powder charge on their measures for every few (several?) degrees drop in temperature from some warm air standard for short range matches so their bullets spin a bit faster in the thicker air. They're spinning bullets at the lowest rpm's needed to just barely stabilize them so those micro-unbalanced ones will still shoot straight.

Note the M40 sniper rifle originally had a 1:12 twist barrel; both the Hart and Schneider barreled ones as made in the early '70's. Some folks wanted 1:11 twists on them so they would still do well in sub freezing temperatures.