308WIN 168SMK 2700 fps recipe

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Paddycakes

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2705 fps on a 168 HPBT on 44.6gr IMR 4064, 22 5/8 Barrel 1:11 twist. Any one else loading around 2700 with their 168s over 4064?
 
Federal loads the 168 to 2650 fps with 43.5 grains. That velocity would be from a 24" standard test barrel, so that'd be about 2615 fps from your barrel. I've not seen an accuracy advantage to driving it harder in .308, and some run it slower. But someone no doubt does it. The Hodgdon data gets to 2766 fps from a 24" barrel, so about 2730 fps from your barrel length. But they use more powder, a different primer and different case, so YMMV.
 
I load all my 308 168 gr. to 2100 fps .
Two reasons I can hit the target and kill any thing in the scope .

What does your loading manual say ???
 
I used to load to 44.5gr IMR 4064 under 168s, but I've since backed off to 41.8gr since the accuracy was every bit as good and I really didn't need the extra velocity for the ranges I shoot 308 at. I tested all the way up to 45gr, which was the max load in my reference at the time.

As long as it shoots tight for you without any pressure signs, it's safe in your rifle under those temperature conditions.

Jimro
 
Scratching my head...

I load all my 308 168 gr. to 2100 fps .
Two reasons I can hit the target and kill any thing in the scope .
Click to expand...

Why would you turn your .308 into a .30-30? Is there not a load that is just as accurate, near or above the 2500 f/s mark?
 
According to Hodgdons website somewhere around 46 gr should get you in the upper 2700's. You should be able to hit 2700 fps easily with a less than max load.

http://www.hodgdonreloading.com/data/rifle

I don't use 4064, but load 165/168 gr bullets with 46 Gr of Varget to about 2750 fps from 22" barrels. These are hunting loads and will put 3 shots under 1". Good enough for me.
 
I have seen conflicting data from multiple sources as to the max load of IMR 4064 under the 168 SMK - as low as 43.4 and up to 45.9c from the Sierra & IMR sites respectively. Wanted to know which number was reliably closer to an actual powder max. I am trying to keep the fps up to 2700 because, for this particular round, keeping a certain trajectory is my goal.
 
The IMR site data (operated by Hodgdon) is the most reliable because they have reference powder to work with. However, it is only reliable if you use the same case and primer they do. Otherwise, especially in your less roomy Norma cases, their load could produce higher pressure. Whether it actually will or not depends on your primer and how much larger your chamber might be and how much longer your chamber's freebore might be than there's was. No way to tell for sure without working the load up and watching for pressure signs. I would guess about a grain less powder for the Norma cases will be in the ballpark if your chamber is as tight as there's.
 
I've done a lot of 168 smk testing with my r700 1-12" varmint and one fact remains clear. After I push the velocities over 2600 fps I see no gain in accuracy. My groups actually get worse. My pet load is 41.9-42.1gr of w748. My barrel loves 2540 fps. Shoots about .6 moa. So imo im just wasting powder and barrel life trying for higher velocities..
 
This may seem wasteful and perhaps even pointless, or perhaps worse still - ineffective, but I am trying to attain a steady 2700 (give or take a lil) fps to utilize effectively the BDC reticle on my nikon M308 scope. I am going purely off the information I am getting by plugging different bullets and speeds into the nikon SpotOn calculator. With the 168 smk at 2700, the projected ballistics make adjusting the reticle for 200, 300, 400, 500, and 600 yards a snap. As long as accuracy remains near MOA I would find this cartridge to fit its purpose. I've got a box of 178gr AMAXs on the way which I will be loading as point on accuracy rounds, as I have found my rifle to do better with 175gr and up bullets for consistency.
In addition, I am trying to diagnose anecdotally an issue I had with a bullet prematurely fragmenting mid-air, and a possible error in readings on my chronograph, which was having trouble staying attached to the barrel during firing.
 
2700fps with 175-178 pills will be smokin fast in 308. Watch for pressure signs working up. IIRC the US mil launches 175's at 2550fps. 10% overspeed is approx 20% overpressure.Best
 
I'm sorry, I didn't mean to infer that I'd be pushing the 178s to 2700. I meant to convey that the 2700 number is important for the 168 round for consistent trajectory, and I will be building more purposefully accurate rounds with the 178 amax, which I assume will be running slower than the 168's most certainly.
 
For my Remington 700 ADL Varmint my go to load is the 168gr SMK or 165gr GK, is 44grs. Of RL 15. My barrel is cut back to 20" and this gives my around 2550fps. The accuracy is outrageous. Best 100yd 5 shot group was .307" center to center.
 
44.6gr IMR 4064 isn't likely running at 2700 fps. Max loads of IMR4064 run at 2766 FPS out of a 1 in 12, 24" barrel, according to Hodgdon.
Pushing the 178s to 2700 would be max loads too.
Where'd you get the idea that the 2700 number is important? 2700 fps was the velocity of .30 M1906 ammo with its 150 grain bullet. Bit less than .30 AP's 168. And the approximate velocity of the 147 grain 7.62NATO M80 cartridge. Really nothing to do with a 168 grain match bullet.
Suggest you throw the Nikon SpotOn calculator away and use a manual. Computer programs are primarily written by people who have never seen a real firearm much less fired one. Far too many variables for any program to be accurate.
"...a bullet prematurely fragmenting mid-air..." That only happens with light varmint bullets that are driven at excessive velocities.
 
I am using 40.5gr 4064 under the 168s smk out of a 1-12, 26" (<-edit I put' not ". 26' barrel would be cool though.) gives great results for paper punching at 200. I have loaded some 168gr A max for dear season this year at 43.5. I don't have a chronograph so I cant say how fast they are, but getting good groups with A max and smk with that load.
 
Hey T'Oheir, thanks for the input, it may have been a malfunction with the chrono, I'll have to try it again. The SpotON ballistics computer was apparently designed to give a person a picture of where in distance (in control conditions I'm sure) the bullet will hit an object in intersection with the fixed points on the ballistics reticle. And not to disagree entirely with your assertion of the nature belonging to the designers of this program, I would say the brilliance of ballistics is in the science of it, while the wisdom lies in the practice, so I turn to both sources. This is all the beginnings of months and years of piddling and experimentation. I was hoping it would be a bit simpler start than this, but because of conflicting data in logbooks and an extremely inconclusive test round, I felt I needed to turn to the experts, both systematic and anecdotal, so again I appreciate the input. BTW I have no plans of trying to push the 178 AMAXS to 2700 fps, just the 168 SMKs for now.
 
P-Cakes :

I get what your driving at but none of us that shoot for accuracy at distance tailor a load to our BDC reticle . You will want to dope your scope by adjusting your turrets . You then can have multiple loads you just dial in the range for. IMO the BDC is for quick shots when you don't have time to dial it up on your turrets . It's very unlikely your BDC will be dead on but doping your scope by using the turrets will be .
 
Paddycakes, it seems to me you are trying to tailor a load for the scope when what you need to do is tailor it for the gun. Once you have done that then plug in the numbers from that load into the Spot-On calculator and it'll give you the information on it.
 
Metal God, Allen J, et al: most wise indeed. This may be an arbitrary exercise for me, perhaps shirking the full responsibility of finding the harmonic personality of my barrel by creating a menial project by which to gain practice in the rhythm of reloading at the work bench. You are all surely correct in your advice and assertions. Metal God, reference check on lingo, "doping" the scope; does that refer either to (a.) logging a zero and then charting the correct adjustment of the turrets to hit mark at other distances in my field book to commit to memory or (b.) something completely different? If (a.) that would be lovely considering the m308 does have those simple turret knobs on which one can adjust zero for convenience.

I want to thank you all for your patience, I'm sure you get a lot of new folks on this forum who make you feel like you could either spend all day changing diapers or just walk away, but I appreciate the guidance. I'd like this to be an art I pass down to a younger generation someday, so this is all very important and pertinent to me.
 
It's "A" . Find your best load for that rifle and base your scopes zero off of that . Then log what adjustments are needed at each distance . Now lets say you work up another load that shoot well but it's point of impact is high and right of the zero you have for the better load . Don't change your zero rather log the adjustments needed to to zero that load . Now when your shooting load "A" your GTG because your zeroed for it but when you shoot load "B" you can look in the book and see you need to come down 2 clicks and over left 3 clicks and now load "B" is GTG

Also when using a BDC as the magnification changes so does the corresponding distance for each hash mark . So when you get a nice accurate load for your rifle . You then can play with the magnification on the scope to get your BDC to match your trajectory a little better if needed in the field .
 
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