308 and the 168 SMK

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hend238

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Hey guys. I have been searching for info on the 168 SMK and what velocities the bullet is most accurate at. I'm coming up short so have decided to tap into the infinite wisdom of CGNuters. There are always a few velocity nodes for a given bullet weight and diameter that provide excellent results. I realize that changes with conditions but a general number is close enough. I can fine tune that number with hand loads to the current condition. For example the 6.5mm 142 SMK excels at 2950 fps more or less...

I'm building a light weight rifle in 308 Win for a little experiment with components I already have, except the barrel. I have to keep the barrel contour light (Remington Standard Contour) to fit the stock and want to keep the length short"ish" to maintain stiffness. Around 22" I was thinking with a 1x12 twist or perhaps a 1x11.25 so I have the option of shooting the 175g bullets. I want to know if I can reach the optimum velocity nodes with a 22" barrel. Target accuracy inside 500 yards is my priority. The rifle will be used for hunting as well but I'm not concerning myself with hunting performance. What ever barrel I screw onto the custom action and hunting bullet I choose will give more than adequate hunting performance on the game I'd likely be hunting for.

Thanks.
 
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Rode said:
I shoot past 1000 yards with a 20" barrel so a 22" will be no problem to 500 yards. You really should use the 175 MK's.
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I'm assuming you are recommending the 175's because of the BC advantage? I thought the 168's were a more accurate bullet for short range? To be honest I'm building this rifle to excel at 300 yards or less. Over that will be mostly for fun and to practice my wind doping.
 
roberti11 said:
I would suggest you start by reading the following....

http://www.shootershaven.net/MarkPic/CGN/DynamicInstability.pdf
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Thanks for that link. I am aware of what was stated in the article though. I do not plan to shoot this rifle beyond the 500 mark. Probably will rarely shoot it past 300 so the problems with stability, transonic range, etc, etc won't be an issue. Therefore I'm not looking for a muzzle velocity that will keep a particular bullet supersonic at long range or a bullet ogive that excels when going through the transonic range. What I want is the velocity node(s) that a 168 bullet is most accurate at. This number exists, I just don't have enough experience with the 308 Win to know it.

Thanks for the input. I will save the above link for future reference as it explains nicely the relationship between stability/velocity/bullet construction.
 
The old standby load for shooting 300m ISU with 168's is 39.0 gr of IMR 3031. Not a fast load by any means but it is accurate at 300m and will poke a hole through paper targets.
 
Developing loads for the 168 SMK is a waste IMO. It's a bullet that is highly likely to tumble once you get past 800 yards. People always start using it with the intent of only shooting short range and often end up wanting to try long range. They show up with their 168 SMK load and surprise, surprise... it tumbles on them.

There are so many other alternatives to this bullet that are more economical, easier to find, better suited to long range and are just as accurate at short range. This notion that the 168 SMK is the best bullet going for short range may have been true 30 years ago, but it's not longer the case. Many new bullets and powders have come along since that time.
 
kombayotch said:
Developing loads for the 168 SMK is a waste IMO. It's a bullet that is highly likely to tumble once you get past 800 yards. People always start using it with the intent of only shooting short range and often end up wanting to try long range. They show up with their 168 SMK load and surprise, surprise... it tumbles on them.

There are so many other alternatives to this bullet that are more economical, easier to find, better suited to long range and are just as accurate at short range. This notion that the 168 SMK is the best bullet going for short range may have been true 30 years ago, but it's not longer the case. Many new bullets and powders have come along since that time.
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Fair enough. However I will NOT be using this gun for long range. I have plenty of other rifles for that purpose in various calibers. This rifle will be for short range ONLY. If I do shoot it beyond 600 yards for example and get poor results I know why and will not be upset. I am not new to shooting and long range accuracy I understand, short range accuracy with the 308 cartridge I do not. I've considered Berger's, have had luck with them but find the VLD's too finicky for my taste. I won't rule them out of course until tested. The scenar could be an option. I mentioned the 168 SMK as I have a s**t load of them on hand. I use them in my Springfield M1A and they s**t the bed around 800 yards as you mentioned. I use 168 Bergers and 175 SMK beyond 700 in my M1A with satisfactory results. Perhaps just mentioning the bullet weight might have been better.
 
It's been known to shoot well around 2600 fps. 42 gr. of Varget or RL-15 will put it there. 41-41.5gr. or IMR4895 or IMR4064. Think one of those last two is the FGGM load...
 
Now we're getting somewhere. Thanks! I know there is no substitute for spending time at the range and reloading bench though. I just want to ensure I order the correct barrel the first time. As I mentioned earlier I'm going down an unfamiliar path.
 
I have managed to get the 168 gr. Berger VLD's to shoot inside MOA out to 1300ish.
After that my bullets start to print angled bullet holes on the target. Then accuracy suffers.

Shoot your 168 SMK's
They will be just fine till you decide to stretch it out past your self imposed 500 yard distance.
As you probably know, let your target tell you what shoots best.
 
kombayotch said:
It's been known to shoot well around 2600 fps. 42 gr. of Varget or RL-15 will put it there. 41-41.5gr. or IMR4895 or IMR4064. Think one of those last two is the FGGM load...
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Those are similar loads I use in my M1A. Perhaps I've had the answer in front of me all this time. I figured comparing what works in my gas gun to what would be ideal in a bolt gun would be a mistake.
 
dthunter said:
I have managed to get the 168 gr. Berger VLD's to shoot inside MOA out to 1300ish.
After that my bullets start to print angled bullet holes on the target. Then accuracy suffers.

Shoot your 168 SMK's
They will be just fine till you decide to stretch it out past your self imposed 500 yard distance.
As you probably know, let your target tell you what shoots best.
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Surprisingly my M1A shoots sub MOA with the 168 VLD's starting somewhere around 400. I have not tried them past 900 though and I don't expect the results will be that good anyway out of a gas gun. My old CG 63 in 6.5x55 LOVES the 140 VLD's all the way out to 600. I run out of sight adjustment so haven't shot beyond that yardage. I'd have to re-zero my sights to get more adjustment. Those are the only two guns I've had great results using VLD bullets. All the others I find a bullet that shoots better or at least find a better load more quickly.

Remember that this rifle project is a little side experiment for me supplemental to my usual shooting styles and why I'm imposing such restrictions on myself. I have a safe full of rifles that fill other niches from Service Rifle to Fclass to Bench Rest to greasing varmints at 100 yards or 1000. But that's not out of the ordinary for most people who have this sickness. :)

I'm looking for advice on the "best" not just "good enough" to achieve short range accuracy with the 308 before I commence with the next step of this project build.

Thanks everyone for their advice thus far.
 
Save yourself the hassel. Buy a T/C Icon. It will do exactly what you're trying to do. Target rifle accuracy but a light hunting rifle.
 
You're missing the point. I already have on hand everything I need to put together a rifle. I just need a barrel. This rifle project will be in line with Hunter Bench Rest equipment rules. I'm limited to how heavy a barrel I can get as the stock I have will only allow a light contour and therefore will be several pounds lighter than what is allowed but it won't be used for serious competition anyway so it doesn't really matter. The Icon has intrigued me in the past though. Perhaps another time I will give it a second look.
 
hend238 said:
You're missing the point. I already have on hand everything I need to put together a rifle. I just need a barrel. This rifle project will be in line with Hunter Bench Rest equipment rules. I'm limited to how heavy a barrel I can get as the stock I have will only allow a light contour and therefore will be several pounds lighter than what is allowed but it won't be used for serious competition anyway so it doesn't really matter. The Icon has intrigued me in the past though. Perhaps another time I will give it a second look.
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I didn't miss your point. I was simply mentioning another option. One that you will find will give your rifle a run for the money while costing a lot less. Yes you have the parts, but if you sold those parts you would most likely be financially ahead with the T/C rather than getting a new barrel. Just another suggestion and possibly something to look into.

Oh and you're welcome for the load data.
 
Forgive me but perhaps I didn't understand yours. :redface:

I have a Stiller action with Jewel trigger, McMillan stock and soon a Broughton barrel. The action and stock I picked up quite a while ago for a song and didn't pay much more than what an Icon in the model I'd buy would cost me. Selling the stock and action in favour of a factory rifle makes no sense to me. IMO and experience a factory rifle including the Icon will never shoot as well as a custom built one. Sure a factory rifle may group well but the the group aggregate over 1000's of rounds won't even be close. Small aggregates win matches, not small groups. The barrel will cost 350 plus gun smithing. I can make use of the action and stock in other combinations so the way I'm looking at it is, I will have another custom rifle for around $500 that will outshoot any of my factory rifles. As long as my gun smith screws the barrel on straight. :)

Sorry If I didn't thank you personally for the load data. I did thank the group, which includes you, for the help. Thk
 
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