Recommended powder for 308

[Curly T]

Starting to develop loads for a trg 22 in 308 win.
Using lapua brass and 175 SMK's. Here in South Africa our selection of powders is somewhat limited, mostly to Somchem' range.
Seeking advice on what powder (or bullets) most would recommend for the 308, keep in mind that I intend to use it out to 1000m.
Thanks!

[Jimro]

Well, you can look for these:

IMR4064
Hodgdon Varget or H4895
ADI 2206H or 2208
VV N140
Reloader 15

Also workable, if you can't find any of the above:
Winchester 748
Power Pro 2000-MR
TAC

If you have the choice, IMR4064 is my preference, followed by H4894/ADI2206H (same powder, different distributors).

Jimro

[Curly T]

Thanks!
As I've said, we're quite handicapped by lack of good powder here, although once in a while some gunshops receive a shipment of the 'goodstuff'
I see we have a local powder, S341, which is suposedly quite similar to imr 4064. Will give it a try!

[jwrowland77]

My choice of powders for .308 are as follows in preference order:

IMR 4064 (600yd load)

Power Pro 2000-MR (1000yd load) Get great accuracy and velocity from 2000-MR

Varget

Reloader 15

H4895

[hartcreek]

you forgot 3031, H414 and even 4831 but asking us will do little good What you have to do is work with what YOU have available in your country. Who ever is selling in your country has to have load data.

[trapper9260]

I use IMR 4064 in jacket and cast bullets and as for the cast i made my own data and loads for a semi auto.

[Jimro]

SOMCHEM's data doesn't include the 175 SMK,

But 180gr PMP SP data
Start 39.5
Max 43.5

168 gr SMK data
Start 40.5
Max 44.5

Based on the V/C data provided, I would split the difference and round to 44.0 as my max charge for the 175 SMK, and a starting charge of 40.0 gr.

Hope this is helpful. http://www.somchemreload.com/search?c=8&f=118

Jimro

[Curly T]

I've tried what local powders we have mostly available. Best load printed 15mm at 200 meters, but accuracy at ranges 450meters and beyond was disgustingly poor, 8'' at 750 meters.
Runout is well within 0.002''
Only after chronographing I discovered the velocity to differ as much as 56 fps.
Brass and bullets have been weight sorted and necks turned.
When I took this up with a mate he agreed to have the same problem with our local powder, which is why I'm concidering switching to a US brand, some gunshops do stock them occasionally and if you know what works you can try and obtain sufficient quantities.

[Curly T]

Thanks Jimro
Yes its very helpfull thanks!

[Jimro]

8" at 750meters is not "disgustingly poor" in my opinion as it is just under MOA. That meets the US Army sniper standard for weapon and load.

Everyone would like to shoot one hole groups at long distances, but even a bughole target load at 100 meters has to deal with atmospheric induced scattering over the length that is a significant fraction of a kilometer.

If 56 fps is measured, try sandbagging your rifle so that the recoil goes into a sandbag instead of your shoulder. If that tightens up the extreme spread the load is good, and your shouldering technique is the culprit.

Jimro

[Kosh75287]

I'm by no means an expert in long-range rifle matters, but I'm wondering about your criterion for success in this investigation. 15mm at 200 meters works out to about 0.27 moa, which, to me, is phenomenal from a rifle with any real portability.

8" at 750 meters (about 825 yards) is STILL under 1 moa. Extrapolating the accuracy at 200 meters to 750 meters would equate to a group no larger than 56.25 mm. Granted, I'm probably no better than average skill with a rifle, but I've NEVER heard of groups that tight from any firearm not mounted on a very large block of concrete.

For me, breaking dinner plates at 400 yards most of the time (I shoot a Springfield Armory M1A National Match) means I'M having a VERY good day!

What type of groups are you hoping for at 750 meters?

[Unclenick]

Curly,

QuickLOAD suggests S341 or compressed S355 are your best options. Which one will shoot better for you is something you'll have to try out. In QuickLOAD both powders use 0.977 times as much powder for the 175 as for the 168, so if you multiply your listed 168 loads by that factor, that is likely about where you will end up. So, for the data Jimro looked up for the 168, you should start at 39.5 grains and work up toward 43.5 grains, same as for the listed 180 grain SP bullet load. The fact the 175 load comes out the same as the recommended 180 grain load is due to shape differences. Despite being heavier, the 180 grain PMP SP is 0.09" shorter than the 175 grain SMK in the QL database, so it takes up less powder space at the same COL.

As bullets go further down range, they are slowing down. This increases the time it takes to traverse each successive 100 meters. That means drift, which is time dependent, is going to grow to a larger number of MOA at long range than it has at closer ranges. That is normal. Worse is wind deflection. It depends approximately on the difference between actual time of flight and the time of flight in a vacuum, where no velocity is lost. This is a much bigger change. You may need depending on spin drift, you may need 10-20 times more wind displacement correction at 750 m than at 100 m and 15-30 times more at 1000 m.

Mind your primer seating:

"There is some debate about how deeply primers should be seated. I don’t pretend to have all the answers about this, but I have experimented with seating primers to different depths and seeing what happens on the chronograph and target paper, and so far I’ve obtained my best results seating them hard, pushing them in past the point where the anvil can be felt hitting the bottom of the pocket. Doing this, I can almost always get velocity standard deviations of less than 10 feet per second, even with magnum cartridges and long-bodied standards on the ’06 case, and I haven’t been able to accomplish that seating primers to lesser depths.

Dan Hackett
Precision Shooting Reloading Guide, Precision Shooting Inc., Pub. (R.I.P.), Manchester, CT, 1995, p. 271."

[Curly T]

Thanks for everybody's input, it is greatly appreciated. Long distance shooting is still in its begining phase over here ( in my neck of the woods anyway) and its tough getting good advise from reloaders and shooters as most are novice to the subject, so believe me when I say I value your inputs!

As to the accurcy, I was expecting to at least get .5 moa groups at 600m and maybe a mite farther.
I'm by no means excluding my own human error out of the equation, as I'm well aware a rifle, no matter how accurate, is only as good as its handler, but I'm sure the rifle is capable of that accuracy, be it my shooting ability or loading components that need attention.

The only reason I suspected my current powder choice, is due the big diferance in velocity spread.
The groups fired at 750m was in perfect wind still conditions and I felt pretty good about the shots.

Thanks Unclenick, I'll try both s341 and s355, so far I've only tampered with s335, as to primer seating, I ream out the pockets with a standard rcbs primer pocket uniformer. But never gave it more thought I guess.

Appreciate the dvice, thanks guys!

[Jimro]

Unclenick,

I don't disagree with you on using the 180 PMP data, but I would like to explain in further detail why I recommended splitting the difference.

The velocity to charge ratio for the 180 at max charge is 58 fps/gr, which also concides with the starting charge for the 168 SMK, which has a v/c for the max charge of 59.4.

It stands to reason that the 175 smk being a boat tail design, not a flat base like the 180 PMP, it should have less bore friction by both mass and heal resistance.

When looking at other data for other powders in a similar burn range (DANGER, don't substitute data between non alike powders) you see a spread of 0.3gr for IMR4064, 0.4gr for IMR4895, 0.7 for H335, and 0.8gr for H4895 AR-Comp and 2000-MR, and 1.0gr for Varget and BLC-2. Going the full grain of reduce max charge to the 180 PMP data may be needed, but based on the burn rates and V/C ratios published, my gut feeling is that the split between the two is 0.5 or less.

Anyways, quickload is backed up by actual data, which trumps my gut, but I wanted to explain my reasoning.

Jimro

[Kevin Rohrer]

Hodgdon BLC-2 is an excellent powder for the .308.

[4runnerman]

Tried many- All said and done it's RL-15 for me. The 308 is a very easy cartridge to load for. It likes so many different combos. The accuracy is very easy to obtain with it. Bullets from 155- 200 gn all shoot great. If you have some RL-15 give it a try. 42.3 gns and a CCI-BR2 or GM210M primers.

[RKG]

What I add at this point won't be much new, but here goes:

I have had excellent results for all of 4064, 4895, Varget, Reloder 15 and 748. After spending more effort than I should have, I have settled on Reloder 15 for the bolt guns (mainly 168 gr. SMKs) and Win748 for the M14. The former, trickled, for accuracy and the latter, metered, for ease of loading.

[tobnpr]

Varget.

Temp insensitive.

[Bart B.]

Curley, I've shot on the Gen. De Wet range near Bloomfontein in the Free State a couple of years at the SA Nationals. Nice range and a great place to shoot. Will you be shooting fullbore matches in SA?

I recommend extruded/stick powders as nobody I know of has shot any .308 Win. load with ball powder worth talking about in accuracy conversations. With 175-gr. bullets (as well as those within 15 ti 20 grains in weight), IMR4064 and those of similar speeds have been producing match winning and record setting scores since 1963.

Accuracy with the .308 Win. in various test setups vary. Machine rests, naturally get the best accuracy. Hand held slung up in prone with a rest under the stock's fore end and toe, can produce groups almost as good as a free recoiling machine rest. Shooting prone without artificial support adds 1 to 1.5 MOA to whatever the rifle and ammo shoots from a machine rest.

Shooting while sitting at a bench with the rifle resting atop something often adds 1 to 2 MOA to the inheirant accuracy of the rifle and its ammo. I don't shoot very precise with benched rifles. And there's easily a 50 fps spread across several people shooting the same rifle and ammo from a bench. Best numbers for muzzle velocity come from shooting prone; the rifle's held more consistantly in position and spreads are typically smaller. It's normal for velocity tests from free recoiling rifles to have 1/4th to 1/3rd the spread compared to hand held rifles shot from a bench.

If you're getting 8'' at 750 meters, that's pretty good; it's just under 1 MOA. How many shots were in that group? I like to test long range loads with at least 15 shots per group; 20 is better. The statistical significance of groups with 10 or less shots is not too good for me. Note that accuracy in subtended angles increases as does range. Groups open up about 10% for each 100 meters/yards past the first 100 due to muzzle velocity spread, the small spread in drag across a batch of bullets and subtle winds that move them around differently. Back this fact off your 1 MOA group at 750 meters and you'll see why your 200 meter group was 1.5cm.

Use the largest groups fired with a given load as their accuracy level. They happen when all the variables add up in different directions. The smallest groups occur when all those variables tend to cancel each other out. Those variables include what's in the rifle, ammo, shooter and atmospheric conditions. Groups will never be smaller than zero when all the variables are zero; their largest ones can be huge.

[Curly T]

Bart
Was very delighted / surprised to see you mention the General de Wet shooting range, have shot there while I was in high school, competing in bisley.

No I wont be shooting fullbore, mostly I use it for plinking and varminting and culling (baboons, springbuck, wildebees) out to 800m. Also alot of my clients use it on occasion on kudu etc.
The only competitive shooting I do with this rifle is whats called 'Field shooting' its a dicipline concisting of 6 courses where the shooter engages targets in the form of steel gongs and life size game animals with score zones on them, distances vary from 50m to 450m with the occasional steel plate at 600m, no artificial rests or pods are alowed, encouraging the competitor to use natural rests such as anthills, logs etc.
Sorry got a bit of topic.

Back to powder
I loaded some rounds, 175 smk behind 40.7gr S341, groups at 200m was good but the weather prevented any further testing. Now the drawback, S341 is, according to Somchem, their most suitable powder for the 308, but its a ball powder.
The only alternatives are S335 (which I've tried and works well at short and mid range) and compressed S355, which I've yet to try.
I'm open to try other bullet weights, but the rifle loves those 175 smk's, and its the only bullet I use in this rifle, be it hunting or competing.

When I shoot groups to determine the accuracy, at longer ranges, I load up 15 rounds of the same powder weight/bullet combination and shoot 5 strings of 3 rounds per string, letting the barrel cool between strings. The average of al 5 groups I then take as the actual group size. Just my way of doing it. So when I say 8'' at 750m, some were better and some were worse, but the aberage of all 5 was 8''
The shooting position was the same: prone , bipod and rear bag
The bipod I am using is the standard sako trg bipod, I like it as it really comes into its own in the field, but if there's a better or more accurate/concistant bipod, or shooting position, or tecnique/style for that matter, please share!!! I dont take offence in the face of good advice!

I go to great lengths ensuring maximum concentricity, trimming metplats, sorting and measuring every variable factor etc etc etc etc, not always convinced this plays such a significant role, but its just the way I do it anyway.

I'm aware of the factors assisting the deterioration of accuracy at longer ranges, the spesific morning I test fired the loads it was absolutely wind stil.
So I'm convinced the bad accuracy lay in the big muzzle velocity spread.
Lets say the powder quality is not the problem, lets say the problem lies with the ammunition and or the shooter.
Is there any reloading tips, techniques, brands or equipment, shooting techniques etc that I can adopt or adapt to lower my differance in muzzle velocity spread?
Thanks for all the inputs guys! Phoned around and actually did manage to locate a couple tins of imr 4064, so very keen to give it a try!
Soon as the weather clears up I'll give it a go!

[Curly T]

Sorry, forgot to ask this.
Can you please elaborate on shooting a rifle 'free recoil'
Its a term I've often come across but not entirely sure what it implies, usually when shooting I give about 85% of my concentration on trigger squeeze and trying to maintain the same amount of pressure with my cheeck and shoulder.
I'm with you on shooting a rifle of a bench, I've seen this work for a great many excellent shooters, unfortunatly I'm not one of them it seems.

[Bart B.]

Free recoil means the rifle is rested on, or clamped into something on, rests under it that let it slide back in recoil not restricted by human contact. It's best done with normally shoulder fired, mild recoiling rifles shooting smaller cartridges. If they don't have much recoil and a light trigger, you can rest them atop bags on a benchtop untouched by you, position the rifle to aim on target, then gently pull its light trigger and let the butt plate recoil back into your shoulder. Here's some examples of free recoiling rifles and how they're used.

http://www.6mmbr.com/gunweek057.html

http://bulletin.accurateshooter.com/...-demonstrated/

Rifles normally fired hand held against ones shoulder can be clamped into a machine rest whose top cradle slides back in recoil. They're so tested for accuracy of both rifle and ammo without all the variables introduced by us humans who never hold anything perfectly still. Here's one used by a USA Nat'l Champion that was custom made back in the 1960's:

https://www.flickr.com/photos/127872...7594303093714/

That rifle's an all metal "tube" gun but is clamped the same way conventional wood stocked ones are. Some have tested .308 Win chambered match rifles at 600 yards shooting several 10-shot groups under 1.5 inches. With a 12 pound rifle clamped in it, the upper cradle recoils back about 2 inches. The muzzle rises in recoil just like it does when shoulder fired so it's an excellent way to test rifles and ammo.

People who've tested ammo with a chronograph with the rifle free recoiling get 1/2 to 1/4 the muzzle velocity spread when the rifle's fired in free recoil compared to holding it against their shoulder as it rests atop something on a bench top. We don't hold rifles very repeatable against us while sitting at a bench.

One's usually better if they sling up in prone position on their belly with the rifle stock resting on a bag under its fore end and stock toe. That's now a typical F-Class competiton position. They typically get better accuracy and muzzle velocity spreads than holding onto a hard kicking rifle at a bench.

[Unclenick]

Originally Posted by CurlyT

When I shoot groups to determine the accuracy, at longer ranges, I load up 15 rounds of the same powder weight/bullet combination and shoot 5 strings of 3 rounds per string, letting the barrel cool between strings. The average of al 5 groups I then take as the actual group size.

If I understand correctly, you take the average diameter of 5 3-shot groups. Be aware that only estimates your what your average future 3-shot group sizes will be, and not how larger groups will behave. It's a smaller result than you would get from a single 15-shot group or by overlaying your 5 targets to count all the holes as a single 15 shot group. This is because the centers of the three shot groups wander around some, where combining them into one 15 shot group causes the differing center locations to be added into the final group size.

The bigger group you then have is less suited to bragging rights, but its center, or mean hole location is a more realistic estimate of your future points of impact than any individual three shot group can make. That is, it is a better estimate of the point around which future groups, be they three shots or more, will have their centers cluster.

Regarding your spherical propellant, if you haven't done so already you should try it with magnum primers. The higher deterrent concentration in spherical powders often causes them to need the higher starting pressure a magnum primer provides to burn at their most consistent. Stick powders often do best with standard primers or even with extra mild primers unless the load fills the case poorly. Extra room left over in the case can benefit from the extra gas from a magnum primer helping pressurize it, too.

You basically just have to try primers out to see which kind produces the least velocity variation for your powder choice. When changing primers, it is a good idea to back the load down 5%, then bring it back up to where velocity matches what it was with the original primer. Often it turns out to be the same charge weight you had before, but sometimes it's not. Hence the caution.

You want to make that 5% reduction no matter which direction the primer change is going in. Or even if it's only a switch from one company's standard primer to another's, or from one company's magnum primers to another's. They are not all formulated the same.

[9MMand223only]

What about VV540? Top Tier accuracy in 308

[Unclenick]

I don't know for sure what he can access. A lot of folks posted suggestions for powders we get here even after he explained he couldn't get most of them in South Africa. I was surprised to see he located some 4064, though, so maybe those suggestions aren't all moot for him. No idea what Vihtavuori's availability in SA is.