Berger 180gn VLD verses 168gn VLD

[Norm]

Hypothetical question for 7mm shooters...........

A 180gn VLD at 2800fps compared to a 168gn VLD at 2950fps.

What is best and why!

[Brad Y]

What ever shoots the most accurate, but would prefer heavier in a head or tail wind.

[DenisA]

Norm, I'm interested in this topic. I know Alan has a lot of experience with the 168's. I think he's said in the past that the 168's don't give the same case issues that the 180's do. The BC is not too far off.

I'm considering running my next .284W barrel on 168's to get the speed up with better case life. I already have the barrel chambered and I don't really want to re-tool, so .284Shehane or SAUM is not an option.

[AlanF]

Hypothetical question for 7mm shooters...........

A 180gn VLD at 2800fps compared to a 168gn VLD at 2950fps.

What is best and why!

180s are definitely better. I wouldn't advise anyone to use 168s !

Seriously, 168s are generally best at the velocities you've given. Wind deflection is the same right back to 1000yds, and with the lighter projectile I've never found case life to be a problem, and slightly less recoil means better behaviour on the bags. I also believe that around 2950 is a universal accuracy sweet spot for target bullets. However with a new barrel I will always try the 180 hybrids first, then if they don't show promise, its back to the 180VLD, followed by the 168VLD. The reason for not going the 168s first is that I'm prepared to push the 180s up to and even beyond 2900fps and trade some case life for wind performance. But accurate 168s at 2950 give very little away to anyone.

Alan

[Norm]

Some good points Alan.
just doing some numbers with my 7-08ai shows a fair advantage to the 168gn VLD in a flatter trajectory. Some disregard this and only think of bullets in terms of how much they drift in the wind. However if the trajectory is significantly flatter then it should tighten up vertical grouping at long range compared to a bullet with a loopy trajectory.

With an ES of 20fps for both 180 and 168gn VLD's at the above velocities, the vertical difference is greater than what the wind drift is when comparing bullets for BC.

When you drive both pills at the range 3500ft/lb muzzle energy limit, things really get interesting.

[plumbs7]

Bryan Litz has Chap 12 dedicated to the issue in his book " Applied ballistics for long range shooting "
In which I gather he favours the 180's over the 168's . But also says on page 178 chapter 11" Your ability to effectively read the wind and properly adapt to the subtle changes is far more important than a few points of bc ".

Ok just ran both projectiles through JBM . 180's at 2800 fps , 10 mph crosswind = 52.74"@1000 yds.
168 at 2950 fps at 10 mph cross wind =53.36"@1000 yds
So roughly 1/2 in diff at those speeds .
IMO the 168's maybe better for vertical sheer as it spends less time in those zones . It's funny though ; in standard there was something magic happen when you pushed 155's at 2990 fps or faster at 1000 yds .

Another point , pardon the pun . Bryan Litz also showed measured data of pointed or unpointed . Bc Berger 168 vld nominal is bc g 7 .316 - pointed .323.

180 vld nominal bc g 7 .337 - pointed .344 .

Norm do you think that you will be able to push the lil 7-08 AI 168 to that 2950 fps ? If it's only 2900 fps then 10 mph wind drift is 54.8" drift . So 2" difference .

IMO 168's maybe better at 300 and even 500 yds in good conditions with the bullet " going to sleep sooner " .
Regards Graham.

[DenisA]

Alan if I have my calc's right, the 168's can legally be run at just over 3050fps. Have you had any success with them up in that area or is the next node above that 2950fps further along?

I'm guessing that pushing them that hard is going to be pushing the brass again.

[Norm]

Norm do you think that you will be able to push the lil 7-08 AI 168 to that 2950 fps ? If it's only 2900 fps then 10 mph wind drift is 54.8" drift . So 2" difference .

IMO 168's maybe better at 300 and even 500 yds in good conditions with the bullet " going to sleep sooner " .
Regards Graham.

Graham,

I am running right at 2900fps with my 7-08ai, Palma brass and 168gn VLD's. The load is not hot and case life is good, so there is room for improvement. In testing I have got to around 2950fps.
If I was using 180gn VLD's I would be running at about 2750fps which is not a hot load either but is at a practical speed for good case life. At 1000 yards the 168gn VLD's still retain a higher velocity than the 180gn VLD's so do get there a bit quicker.

With the popular 9 twist barrels the 168 VLD is stable, the 180gn VLD is right at an SG of 1.50 while the 180gn Hybrid can have a SG below 1.50 under certain atmospheric conditions so may have a slightly lower BC than published. This fits in with what Alan was saying about trying the Hybrids first then the 180gn VLD then the 168gn VLD.

If your barrel is not a true 9 twist and has a slightly slower twist then this could make a huge difference. Take a Button rifled barrel that may have 9.1 twist instead of a true 9 twist, it lowers the BC of a hybrid by 3% according to Berger's twist rate calculator.

I'm not sure just how accurate the twist rate of button rifled barrels is. I think that they can vary quite a bit from what is stamped on them. I received a 6mm button rifled barrel recently that was supposed to have an 8 twist barrel and was stamped as such. It shot terrible and when the twist was checked it turned out to be 9.5 twist. I had to use a much lighter weight projectile to get this barrel to shoot accurately.

Not sure what speed a .284win would get with the 168 VLD's but it should get to 2950fps I would say. Maybe someone could supply some load data. Now a 7mm SAUM with a nice cut rifled barrel in 9.5 twist, would get them rocketing along!

[AlanF]

Alan if I have my calc's right, the 168's can legally be run at just over 3050fps. Have you had any success with them up in that area or is the next node above that 2950fps further along?

I'm guessing that pushing them that hard is going to be pushing the brass again.

I don't recall ever going over 3000 with them except for testing Denis. I prefer to rely on BC rather than velocity for better wind performance. High velocity has a lot of undesirable side effects.

[Brad Y]

Alan- how many firings would you expect to get in a shehane with 2209 and 168's at the 2950fps node? I have been speaking with Denis for a bit about 168's in the shehane in an attempt to save cases and also due to the unreliable supply of 180's. I would still prefer the 180gr hybrid in rough conditions particularly into a head or tail wind, but in short ranges and more constant conditions would be happy to use a 168gr load and learn where to point the gun.

[AlanF]

I wouldn't like to give you wrong information Brad - I use mainly N165, and with that the primer pockets have never been a problem with 168s. Plus I normally stop using brass at most 8 to 10 firings, so don't really know what happens after that.

[RDavies]

Some of my best barrels have LOVED the 168s pushed at a faster speed. While I use 180s in most barrels, some of the tighter ones went well with the lighter pills. I will be trying 168s in my latest 284 which shows early pressure signs with 180s, even if the 168s are just for up to 700-800yds. I think the reason that 168s MIGHT be better on target then ballistics charts show is that some barrels are not a true 9" twist. It is only lately that the experts have proven what I had long suspected is that 180s MIGHT not be fully stabilized in 9+" twist barrels and so show more wind drift than they should Especially in cool weather like we get. The 168s always seems consistent even in cold weather, likely because they were always fully stabilized.

[Brad Y]

I wouldn't like to give you wrong information Brad - I use mainly N165, and with that the primer pockets have never been a problem with 168s. Plus I normally stop using brass at most 8 to 10 firings, so don't really know what happens after that.

Thanks for the honest response. I hope you have good stocks of N165 as I heard on the grapevine its going to be hard to source in the future.

[dave]

having used and played with a number of 7mm's since 2000, i am amazed with some of the velocities quoted in this discussion.

i am not saying they have not and are not being achieved, but in my rifles i could not successfully run these velocities without enduring excessive pressure and short case life.

maybe the apparent strength of savage actions ??? and the indicated accuracy of my chronographs might be responsible for my “on average much lower velocities”achieved in the rifles/calibres referenced as follows.

the acceptable pressure/ working velocities i could achieve were:-

7x53 improved (7mm/30wsm case) on a savage action with 28" tobler barrel (9.5 twist) - 168vld @ 2920fps 175 sierras @ 2860fps (note 180's were not attainable at the time)

7x57 improved -barnard action - 28" tobler barrel (9.5 twist) - 175 sierras @ 2700 fps-162 a max @ 2750fps (at 2810fps primers blew) - 168 vld @ 2720fps

7x63 (280 ackley reamer ran in short to suit 30-06 lapua brass) savage action 30" tobler barrel (9”twist)- 175 sierras @ 2840fps- 168 vld @ 2880 fps – 162 a max- 3010fps- 180 vld @ 2750fps-

280 ackley-savage action-28” tobler 10” twist (won’t stabilise anything over 168grains to 1000yds) - 162 amax@2920fps - 168 vlds @ 2820fps

7x63 –savage action-28”kreiger (9”twist)- 175 sierras @ 2720fps (2780fps excessive pressure) -162 a max@ 2880fps -168vld @2800fps- 180 vld/hybrids @ 2700fps

7mm Jacko (similar to 7mm Boo Boo) – big BAT action 30”Bartlein barrel (9” twist) - 180vld/hybrids @ 3050fps (near max) - 175 sierras @ 3080fps -162 a max @ 3240fps (near MAX)

cheers
dave g

[plumbs7]

having used and played with a number of 7mm's since 2000, i am amazed with some of the velocities quoted in this discussion.

i am not saying they have not and are not being achieved, but in my rifles i could not successfully run these velocities without enduring excessive pressure and short case life.

maybe the apparent strength of savage actions ??? and the indicated accuracy of my chronographs might be responsible for my “on average much lower velocities”achieved in the rifles/calibres referenced as follows.

the acceptable pressure/ working velocities i could achieve were:-

7x53 improved (7mm/30wsm case) on a savage action with 28" tobler barrel (9.5 twist) - 168vld @ 2920fps 175 sierras @ 2860fps (note 180's were not attainable at the time)

7x57 improved -barnard action - 28" tobler barrel (9.5 twist) - 175 sierras @ 2700 fps-162 a max @ 2750fps (at 2810fps primers blew) - 168 vld @ 2720fps

7x63 (280 ackley reamer ran in short to suit 30-06 lapua brass) savage action 30" tobler barrel (9”twist)- 175 sierras @ 2840fps- 168 vld @ 2880 fps – 162 a max- 3010fps- 180 vld @ 2750fps-

280 ackley-savage action-28” tobler 10” twist (won’t stabilise anything over 168grains to 1000yds) - 162 amax@2920fps - 168 vlds @ 2820fps

7x63 –savage action-28”kreiger (9”twist)- 175 sierras @ 2720fps (2780fps excessive pressure) -162 a max@ 2880fps -168vld @2800fps- 180 vld/hybrids @ 2700fps

7mm Jacko (similar to 7mm Boo Boo) – big BAT action 30”Bartlein barrel (9” twist) - 180vld/hybrids @ 3050fps (near max) - 175 sierras @ 3080fps -162 a max @ 3240fps (near MAX)

cheers
dave g

Thanks Dave for sharing that info as its very interesting . Maybe try with another chrony ? It's seems slow.
As for amazed . Like I said before , I am amazed what my barrel is achieving with 180's but is showing small signs of pressure