.308 heavy bullets

[ai308]

Hi,

 

does anyone have experience with heavy .30 cal bullets (like 208gr Hornady ELD-M) and a 10" twist 26" .308 barrel?

Would a short action system (AX308) be fine for those, or would I face issues when seating them to magazine length? (powder volume, mag length vs touching the lands)

How do they perform compared to rounds in the 6.5 calibre?

 

Thanks a lot!

 

[Chanonry]

I have shot most things out of a 308 from 100 to 200 Accubonds (damn good woods round) and the 208 Amax. Can't remember if I ran them out of the AX but i don't think so, but defo in my Sako 75 Varmint 24" 1:11.

Stability was fine. The 208 was genuine 1/2 moa (i.e. not discounting 'fliers').

Would they be 'fine'? Depends on your definition of fine I suppose. Certainly accurate enough for me. I did not tune either load or CBTO. I just ran a full but safe load. I was all just playing about. I am assuming the length of the ELD and the Amax will be similar as the 208 was the only 308 bullet in that range that had a properly designed boat tail so the ELD can't be that different. 

I ran RL17. Filled it close to max pressure. If you go that route just be careful of working up a load on a cool day then shooting them on a scorcher.  I had some hard bolt lifts never mind what the advert says.

In the Sako I loaded to mag length so COAL was 2.90" not the SAAMI 2.80" which helped me get a bit more velocity. In reality it probably did not make a huge difference.

I just measured my Accuracy International double stack magazine and it gives me 2.980", so even more room there. 

Fundamentally though, the 208's they are too heavy for the 308 case to produce anything other than a droopy trajectory.

The benefits of this approach are you get a high bc bullet in a 308 so good wind drift for a 308. The downsides are: low mv therefore more drop; and of course more recoil.

In comparison to a 6.5 ? Totally different. The 208 has good Windage for a 308, but much more drop and much more recoil. Not the same experience at all.

If you want to get the 308 to make a more general impression of a 6.5 short action then something like the 155 Berger Hybrid will give you drop, recoil that's a bit more like it while giving better than average wind performance.  Other guys may have different views.

In reality its never going to compete with the long slim modern 6.5 bullets(in terms of external ballistics). The 140 Berger hybrid etc etc will kick its ass any day.

Still cheaper than a new barrel... ?!

[ai308]

9 minutes ago, Chanonry said:

I have shot most things out of a 308 from 100 to 200 Accubonds (damn good woods round) and the 208 Amax. Can't remember if I ran them out of the AX but i don't think so, but defo in my Sako 75 Varmint 24" 1:11.

Stability was fine. The 208 was genuine 1/2 moa (i.e. not discounting 'fliers').

Would they be 'fine'? Depends on your definition of fine I suppose. Certainly accurate enough for me. I did not tune either load or CBTO. I just ran a full but safe load. I was all just playing about. I am assuming the length of the ELD and the Amax will be similar as the 208 was the only 308 bullet in that range that had a properly designed boat tail so the ELD can't be that different. 

I ran RL17. Filled it close to max pressure. If you go that route just be careful of working up a load on a cool day then shooting them on a scorcher.  I had some hard bolt lifts never mind what the advert says.

In the Sako I loaded to mag length so COAL was 2.90" not the SAAMI 2.80" which helped me get a bit more velocity. In reality it probably did not make a huge difference.

I just measured my Accuracy International double stack magazine and it gives me 2.980", so even more room there. 

Fundamentally though, the 208's they are too heavy for the 308 case to produce anything other than a droopy trajectory.

The benefits of this approach are you get a high bc bullet in a 308 so good wind drift for a 308. The downsides are: low mv therefore more drop; and of course more recoil.

In comparison to a 6.5 ? Totally different. The 208 has good Windage for a 308, but much more drop and much more recoil. Not the same experience at all.

If you want to get the 308 to make a more general impression of a 6.5 short action then something like the 155 Berger Hybrid will give you drop, recoil that's a bit more like it while giving better than average wind performance.  Other guys may have different views.

In reality its never going to compete with the long slim modern 6.5 bullets(in terms of external ballistics). The 140 Berger hybrid etc etc will kick its ass any day.

Still cheaper than a new barrel... ?!

Hi Chanonry,

thanks a lot for your feedback. I' was just impressed by the high advertised BC of those. But I also suspected, that the attainable velocities with the .308 cartridge would be pretty low. Basically, .308 will remain a .308 . I've just checked some ballistic tables with AB and compared them to the .260rem. Not that impressive.

Maybe I should tell you some background information: I got a 2013 AX308 some years ago. It has a 20" 1/12" barrel. Means, I'm a bit limited with my bullet choices. I've been running 175grSMK out of it, which were fine up to 800m (was limited by the range available) . Also tried the 175TMK. Groups were fine at 100m, but had no chronograph at this time. Then I recognized, that Sierra recommends at least a 1/10" twist for the 175gr TMK.  I've verified it with Berger twist rate calculator , which confirmed that. Finally, I created a list containing bullets from Lapua, Hornady, Nosler and Sierra between 155gr and 185gr which are regularly available at my location. I sorted them under the criteria: BC / stability, availability, price. When it was about the BC,  the 175SMK was still the best choice, at least according the twist rate calculator.  Interestingly, the 175 gr ScenarL was a bit worse and the 155gr Scenar was in the range of "marginal stability". Besides the 175gr SMK were just 2 168gr bullets left:  the Nosler CC and the Hornady HPBT match, which I'm running today. I know, there are better choices than the 168gr for ranges over 800m. But unfortunately, I don't have enough range available near my place to verify those at distance. That's why I try to find a bullet which at least got the performance 'on paper' and do some load development and velocity testing for the competition. I would continue to run the 175gr. SMK, but they're a bit pricey. I don't know, how the 155 Scenar  and 175 Scenar L would perform with 1/12" barrel in real life. Just the twist calculator kept my away from them.

Maybe you got some experience?

 

Now about the heavy bullets. Last year, I extended my collection and got another AX308, model 2014 and a custom .260rem, 26", 1/8" barrel, which shoots great. But I'd like to have some improvement on the 2013 AX as well and the 1/12" twist 20" barrel is a limiting factor. That's why I had the idea to replace it by a longer 1/10" barrel. But as everything in life, it's just a compromise.

 

[20series]

I used to shoot 175smk from my original Remmy 700 PSS, it was 1/12 IIRC I was using 45.5gn of Varget, out to 800 yards it was awesome but obviously started falling off after that.

When I decided to get into F-TR I had it rebarreled with a 32inch 1/10.  I settled on 200gn SMK with 46gns of RL17/Elcho17/RS??

That gives me 2700fps which is supersonic out past 1200 yards, 

 

Alan

[VarmLR]

I shot both 190 smk and 175 TMK from my 1/11 twist 24 inch tube using RS single base RS50.

Loaded to 2.800 OAL.

Velocities for both were circa 2600fps and 1000 yard performance was very good indeed, with my best 20 shot group from a factory rifle being moa.    You mention 1/2 moa....at what range and what was the group size?  100 yard groups tell you nothing about 1000yd performance.  You need to tune for low ES and low SD.

I found the venerable old 190 smk to be a good bullet and does allow the .308 to be a genuine 1000 yard proposition. Ditto the TMK.  There's better about but they're considerably more expensive to shoot.  Your 208grn should be plenty good enough if by "good enough" you mean long range practice and fun but you may find the 175 TMK well worth a look and should be able to achieve respectable velocities from your barrel with that bullet.

There's little point comparing a .308 to any 6.5....if you want a 6.5, buy a 6.5 or a 7mm for the BC advantage.  I shoot both cals using factory rifles and tbh, do almost as well with the .308 as I do with the 6.5 because when conditions are challenging, it's the ability to call the wind, thermal effects and other variations, some which may be peculiar to each range that matter so unless you're already a seasoned and experienced long range shot, the .308 is a great calibre to practice and learn from, precisely as it show cases variations slightly more than 6.5 cals.  

Practice with a .308 is also cheaper.

[Chanonry]

18 hours ago, ai308 said:

 

Maybe you got some experience?

 

Well my thought would be...

Aside from  - never shot the 175 TMK, (is it just tarting up an old faithful to save costs without really being best in class ? No idea. I shoot loads of Sierra stuff so not a hater ) and can't comment on its relative merits. Comments purely on my experience.

The key point is - It depends what you want from your trajectory...

In normal rifle configuration my feeling is that 208 is too heavy for the 308, the trajectory has too much drop due to velocity constraints from the case size. 180 ish feels like the upper limit, with 150 ish being the bottom end (below this, it is flat but toooo wind affected). No surprise, but all of this is of course subjective and application dependant. 

For known distance wind is everything situations , then 208 type stuff wins (possibly) BUT you really need a target style  set up i.e. longer barrels and load the bullet long ("longer/long" again being subjective or defined by competitive challenges) -> more powder and more barrel = more pressure for longer = more mv

1. Its really about form factor (pointyness, and boat tail really) rather than BC as this is a purer measure of aerodynamic efficiency which is the main driver of wind drift. Higher BC can still have a less efficient shape and seem better simply due to higher weight therefore it can misrepresent relative performance in the wind.  Hence the comment about 155hyd - lower bc but good form factor - 0.953 giving 'good' wind performance and a 'flat' trajectory. Plenty other examples at different weights.

2. That's all good in theory but it depends on what you can get in practice i.e. its all a bit marginal and if your powder bullet combo turns out not to work for you despite the theory, then you have to look elsewhere.  I find quickload saves me a lot of money as it can give me a feeling for what combinations really do have potential rather spending to try stuff out.  

This thinking applies at higher weights as well so other thoughts would be to copy Lowlight on Snipershide who in one of his articles about switching to a 6.5 gave an alternative approach and shot a Berger 185gr Juggernaught over 2000MR out of a 20" barrel (I think). Not up to a 6.5 but his performance was impressive and his point was that just cos 6.5 is good there is no need to give up on the 308 as with modern powders and bullets we can see some good performance improvements as well.

Sorry, I had a quick google but could not find the article. Never went that way but it may work better for you if you are already at the 175gr end of the scale. According to Berger the 185 will stabilise out of a 1:11 (no pointy plastic bit) and has a form factor of 0.981. There is also a 185gr hybrid that has 0.944 and needs a 1:10

Underlying all this stuff is that many of  the 20th century bullet designs are less aerodynamically efficient (i.e. lower form factor as per Bryan Litz) than many of the 21st century designs. After all that is really what is behind the upsurge of the 6.5's. If you put a crappy old 20th century bullet in a 6.5 Creed then guess what, it behaves like a 1980's 6.5 Swede. Who knew...

[VarmLR]

The 175 TMK is probably the best .308 bullet I've shot at 1000 from a relatively short 24 inch tube and exhibits less wind drift than the 155's I was shooting at much higher velocities, form factors an' all considered, but that may nor be the case for everyone.  There are better bullets in a similar class of course, and the 185 Juggernaut is probably one of them.  It depends on barrel length and whether a barrel likes a particular bullet too.  No point in using 155's from a 20 inch barrel as you simply can't get engugh velocity from them to make them work well at 1000 for example, irresepctive of all their pointiness or boat-tailiness, whereas the 175 TMK works very well and can be kept above transonic (easily as it happens in my own 24 inch barrel length). 

Generalisations are just that and high BC I would have thought does indeed point to what sort of wind bucking performance to expect, along with the form factor and the velocity (ie they need to be considered together to get the full picture). Any ballistic app can churn out wind drift and comparing each bullet for a 10mph wind using an app is as good a way as any to do the homework before trying a bullet to compare.  There's little point either in talking about how flat shooting a bullet is if the guy asking the question can't get the velocities in his rifle to make the comparison worthwhile, so when comparing bullets, I guess you have to take a punt at what sort of velocities are realistically expected in each bullet class for the rifle they're to be shot in.  What works well in a long barrel may be out-classed in a shorter barrel by heavier, higher BC bullets.  At least that's my own findings with .308.

The 6.5 is a different proposition entirely.  For example, you can make the 123gr scenar work as well as, or better than the 139gr higher BC bullet simply because it can be driven fast enough, even in shorter barrels, to give it the edge.  I have considered the #2156 new Palma in my own .308 but with factory chamber, I can't get it close enough to the lands to make it work properly, as it isn't jump tolerant...another consideration when comparing bullets.

[ai308]

2 hours ago, VarmLR said:

The 175 TMK is probably the best .308 bullet I've shot at 1000 from a relatively short 24 inch tube and exhibits less wind drift than the 155's I was shooting at much higher velocities, form factors an' all considered, but that may nor be the case for everyone.  There are better bullets in a similar class of course, and the 185 Juggernaut is probably one of them.  It depends on barrel length and whether a barrel likes a particular bullet too.  No point in using 155's from a 20 inch barrel as you simply can't get engugh velocity from them to make them work well at 1000 for example, irresepctive of all their pointiness or boat-tailiness, whereas the 175 TMK works very well and can be kept above transonic (easily as it happens in my own 24 inch barrel length). 

Generalisations are just that and high BC I would have thought does indeed point to what sort of wind bucking performance to expect, along with the form factor and the velocity (ie they need to be considered together to get the full picture). Any ballistic app can churn out wind drift and comparing each bullet for a 10mph wind using an app is as good a way as any to do the homework before trying a bullet to compare.  There's little point either in talking about how flat shooting a bullet is if the guy asking the question can't get the velocities in his rifle to make the comparison worthwhile, so when comparing bullets, I guess you have to take a punt at what sort of velocities are realistically expected in each bullet class for the rifle they're to be shot in.  What works well in a long barrel may be out-classed in a shorter barrel by heavier, higher BC bullets.  At least that's my own findings with .308.

The 6.5 is a different proposition entirely.  For example, you can make the 123gr scenar work as well as, or better than the 139gr higher BC bullet simply because it can be driven fast enough, even in shorter barrels, to give it the edge.  I have considered the #2156 new Palma in my own .308 but with factory chamber, I can't get it close enough to the lands to make it work properly, as it isn't jump tolerant...another consideration when comparing bullets.

Did you also try the Hornady 178gr ELD-M?

[VarmLR]

No.  Didn't fancy paying those prices.  The TMK works well for me.

[Richiew]

Hi all 

have tried amax 155s, lapua 155s normal type and the L version ,also 155tmks and berger 155.5 fullbore . by far the best are bergers loaded at 2.85 coalwith 42.5 gr of N135  5 shots .5 moa at 100 - 300 m  . 2nd best were amax loaded at 2.8 coal .next up 175 bergers  even better with 44.5 gr of N550 ,10 shots through a half inch hole at 100m. next batch to try are berger 185 juggs with N 550 powder loads as per berger manual . 185s loaded to 2.9 coal just like the applied ballistics bullets re bryan litz and now made by berger . 2.9 coal gives 36 thou jump to lands in 26" AI AT 308 rifle with the 185s. moving on to try neck and bump bushes to size cases with 2 thou tension on the bullets , going to use up the N 550  then use N 150 for the 175 and 185s as it can be bought in big cans . hope the info helps 

cheers richie

[ai308]

Thanks a lot, guys!!

[Richiew]

Just for info the 185 bergers were good, but not what I expected they are same size as the 175s but obviously a tad heavier . they do seem to give more recoil both in push against shoulder and some torque/ twisting  compared to the 175 or155.5 's . this makes them harder to stay on target through the scope  .  cheers 

[TJC]

I’ve tried the 208gr in my .308 but couldn’t push them fast enough without pressure signs to really exploit their high BC. 

[VarmLR]

That's the sting with .308 heavies in anything other than a long barreled rifle.  To really exploit them, one might expect best results from a 30 or 32 inch barrel with a slow burning propellant but even then, a 24 inch barreled off the shelf 6.5 or 7mm would most likely outperform them.  You might also expect increased barrel wear from  longer .308 bullets once you start driving them hard.  My own limited experience suggests that a nice compromise lays in the high BC ballistic tipped .308 up to perhaps the 190s if shot from a  shorter (say 20 to 24") barrel.  185 Berger "Juggernauts"  when you can get hold of the things, would be my ideal heavies for my T3.  Short of that, I tend to favour the 190 smks overall as they are readily available and not too pricey...and work well at 1000 yds with moderate N150 loads.  F-class tend to shoot longer barrels with lighter bullets driven good and hard (the155gr Palma typically delivered at over 3000fps MV). 

[Richiew]

What loads of N 150 for the 185 juggs have poeple found to work well ?? also whats the speed ? .

cheers