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Discussion Starter #1
Howdy All,

I was out in Phoenix taking a class, when one of our instructors pulled out a new POF 16 inch rifle and wondered how it would do. He sighted in a Leupold 2.5-8 Mark IV scope at 100, then went out to 250, 520, and on, up to 920. He could get hits, on demand, on an IPSC size target at 920 yards, and he did it with 2 minutes less elevation than the rest of us with 308 bolt guns.

With that said, if he was connecting with that target using 77grain Black Hills, shouldn't an 80 or 85 grain, aerodynamic, 6.8 caliber bullet going 3000 fps at the muzzle perform just as well, if not better?

Am I correct in saying that the ballistic coefficient of the 6.8 is better than than the 223? That means it should fly better than 556, right?

I am not asking if it would still be minute of angle at 1000, but do you think we could get body hits on a man sized target at 1000 with a 16 or 18 inch SPR type weapon?

Any experience with this?

I am new to the precision rifle world, any and all info is appreciated.
 

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CUSTOM1911FAN said:
Howdy All,

I was out in Phoenix taking a class, when one of our instructors pulled out a new POF 16 inch rifle and wondered how it would do. He sighted in a Leupold 2.5-8 Mark IV scope at 100, then went out to 250, 520, and on, up to 920. He could get hits, on demand, on an IPSC size target at 920 yards, and he did it with 2 minutes less elevation than the rest of us with 308 bolt guns.

With that said, if he was connecting with that target using 77grain Black Hills, shouldn't an 80 or 85 grain, aerodynamic, 6.8 caliber bullet going 3000 fps at the muzzle perform just as well, if not better?

Am I correct in saying that the ballistic coefficient of the 6.8 is better than than the 223? That means it should fly better than 556, right?

I am not asking if it would still be minute of angle at 1000, but do you think we could get body hits on a man sized target at 1000 with a 16 or 18 inch SPR type weapon?

Any experience with this?

I am new to the precision rifle world, any and all info is appreciated.
I'll put up the numbers in a minute, but the Hornady 110 Gr. V-Max, BTHP, and HP have pretty much the same BC, velocity, and trajectory as the 75/77 Gr. bullets.
 

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Here are the trajectories for the 77 Gr. SMK out of a 16" barrel with a MV of 2600FPS and a 100 yard zero:

Calculated Table
Range Drop Drop
(yds) (in) (moa)

100 -0.0 -0.0
200 -3.7 -1.8
300 -15.1 -4.8
400 -36.0 -8.6
500 -69.0 -13.2
600 -117.2 -18.6
700 -184.8 -25.2
800 -276.5 -33.0
900 -397.1 -42.1
920 -425.2 -44.1

Here are the trajectories for the 110 Gr. V-Max out of a 16" barrel with a MV of 2600FPS and a 100 yard zero:

Calculated Table
Range Drop Drop
(yds) (in) (moa)

100 -0.0 -0.0
200 -3.6 -1.7
300 -14.9 -4.8
400 -35.6 -8.5
500 -68.0 -13.0
600 -115.1 -18.3
700 -180.3 -24.6
800 -268.1 -32.0
900 -383.0 -40.6
920 -409.6 -42.5

Here are the trajectories for the 80 Gr. bullet out of a 16" barrel with a MV of 3000FPS and a 100 yard zero: (I estimated the BC at .225).

Calculated Table
Range Drop Drop

(yds) (in) (moa)
100 -0.0 -0.0
200 -2.7 -1.3
300 -12.6 -4.0
400 -32.8 -7.8
500 -67.8 -12.9
600 -123.8 -19.7
700 -208.1 -28.4
800 -327.8 -39.1
900 -489.1 -51.9
920 -526.9 -54.7
 

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Discussion Starter #4
Interesting,

Looks like the heavier bullet does better past 600 yards. Seems to me that the 110 may be one of the best all around performers. Do you have any data on the 130 grain bullets?

I guess I am captain obvious, but I take away from this that even though the heavier bullets start out with a lower muzzle velocity, they retain their energy at the longer ranges.

I also think that building an 18 or 20 inch barrel SPR would help me out to 1000 by giving me a higher muzzle velocity to start out with.

Thanks for the info.
 

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CUSTOM1911FAN said:
Interesting,

Looks like the heavier bullet does better past 600 yards. Seems to me that the 110 may be one of the best all around performers. Do you have any data on the 130 grain bullets?

I guess I am captain obvious, but I take away from this that even though the heavier bullets start out with a lower muzzle velocity, they retain their energy at the longer ranges.

I also think that building an 18 or 20 inch barrel SPR would help me out to 1000 by giving me a higher muzzle velocity to start out with.

Thanks for the info.
Here are the trajectories for the Speer 130 Gr. SP out of a 16" barrel with a MV of 2400FPS and a 100 yard zero:

Calculated Table
Range Drop Drop
(yds) (in) (moa)

100 -0.0 -0.0
200 -4.6 -2.2
300 -18.0 -5.7
400 -42.0 -10.0
500 -79.0 -15.1
600 -131.8 -21.0
700 -204.1 -27.8
800 -299.6 -35.8
900 -422.7 -44.9
920 -451.0 -46.8
 

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Re: Can 80 or 85 Grain Bullets Make 1000 Yards?

Paulo,

Thanks for the posts...It was an eye opener.

The 110g does indeed look like an over achiever in the 6.8SPC

I'm sure the BC of the 110g Pro Hunter is not as good as the V-Max due to the ogive shape and flat base...but I wounder how much the trajectory would suffer using the PH.

Kerry
 

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The 110 Ph has the same traj and drop as the 130 speer SP.

The best bullet right now for LR is the Accubond.

Of all the 110 bullet the PH can be loaded to the highest vel and the Vmax to the lowest. the AC falls in between.

For lower cost target work at ranges out to 600 the 90 TNT does very well and actually shoots inside(less drop) then all the popular .308 and Grendel rounds. If thy put a tip onth85 gr TSX it would have a BC in the ow to mid .300 and woudl dust any and everything current.


The issue with any of these round and your question of 1000 yards. Non of them will still be super sonic at 1K and going thru the transonic barreir is very violent and most bullets destabilize some what. With single loading length rounds you can make 1K with some bullets for sure.

The 6.8 simply is not designed to work at those ranges. Heck ti was orginally suppose to go 500 max and we now have it pushing past 800.That about a 40% increase in max distance and this is without a LR bullet designed specifically for the unique specs of the 6.8.
 

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Discussion Starter #8
Tim,

I am very happy to see how far the cartridge has come since its inception. I am even more pleased to see that the development of this round seems to be largely a grass-roots effort. Rare these days.

Regarding bullets for 6.8-Is there any news as to when the major bullet manufacturers are going to build a 6.8 match bullet that is specifically designed/optimized specifically for the cartridge?

I would imagine its been around long enough to attract the attention of somebody who makes bullets. I saw a design for the perfect bullet posted on this forum-it may have been yours, as a matter of fact.

Do we need to start a letter writing campaign to get something going?

Thanks,

Billy
 

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Discussion Starter #9
Paulo,

Thanks for the data, much appreciated. I am going to print these tables off and use the figures as "try dope" to get my scope in the ballpark, and refine the data from there. Once I get going, I'll send you feed back as to how far the program is from the results I get. Based on the results of your posts, I am going to spend most of my time with the 110 grain rounds from SSA.

Thanks,

Billy
 

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There is some work going on right now with bullets and hopefully the 1rdst quarter of the year will have something.

Don't bother printing those drops out. You can make your own using the same JBM program Paulo I and most people use cause its online and free. I have my own more complex and accurate one but use th JBM as that keeps everything even.

Go here http://www.eskimo.com/~jbm/calculations ... _card.html Change the height of scope from 1.5 to 2.75 .

Then it will spit it out in the right size for a trajectory CARD.
 
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