Optimum weight for 1000y, .308

[Farmer Rob]

Hi all,

After reading heaps of posts her and elsewhere, i think i have been led up the garden path.

I have been told I should use a 150gn projectile to shoot 1000 yards, is this too light, what do you guys use.

My rifle is 308, 22 inch barrel with a 1 in 10 twist. Trigger job done, strengthened synthetic fully floated stock, bedded as best as can be, according to my smithy.

So what is the optimum weight and how heavy or light can i go

Thanks in advance
Rob

 

[Lefty7mmstw]

Re: Optimum weight for 100y, .308

I don't use the 308 myself, but a 150 is a great bullet to 400-500 yards for deer in the 308/30-06. Longer range, and you will want to move up to a 178 match or so weight wise. The 308 starts to suffer to much speed wise when you get much heavier.
The 155 Palma also comes to mind, but that is for the Palma competition where bullet weight is locked to 155gr to level the playing field.

 

[lloydsmale]

Re: Optimum weight for 100y, .308

Im a hunter not a paper target shooter. Ive hunted with 06 and 308s for proably 40 years or more. Ive used bullets from 150-180 in both. Anymore when i hunt with either i use nothing but 150 cup and core bullets. I limit them to about 350 yards. Maybe a touch more with the o6. Ive yet to see any animal walk away from one. I prefer the 150s because they tend to knock animals down quickly. the 06 is very popular up here like it is in many places. Id bet i did more tracking of wounded deer shot with 180 grain 06s then all other rounds combined. Most 180 grain .30 cal bullets, even cup and core bullets are designed to hold up to 300 mag velocitys and dont open up well on light skinned deer, especially at longer ranges. There not a good recipe for quick kills. 165s might be a good compromise but with the luck ive had with 150s ive never seen a need to change.

 

[Lefty7mmstw]

Re: Optimum weight for 100y, .308

Back in the day when I fielded an '06, I used the 165 hornady boat tail with a stiff charge of 4350 and a mag primer. Using h414/760 or similar you would be very close to the 2900fps I was getting with this, at least 2800. The nos bt has a bit better bc and a softer nose, so it may be a better option.

 

[rscott5028]

Re: Optimum weight for 100y, .308

I like the 175gr Berger OTM with Lapua Brass, CCI BR2 primers, an IMR4064 powder running around 2650 fps from a 20" 1:10" barrel, suppressed.

They feed nicely from the AICS magazine.

For a single shot, there are some higher BC bullets in that weight range. I'd be leary of going much over that in a 308 unless you've got it throated long. Otherwise, you'll lose case capacity and MV.

-- richard

 

[Nomad]

Re: Optimum weight for 100y, .308

If all you are shooting is a target at a 100 yards then the speer tnt 130gr will work.
Shooting game would stick with the 150gr bullet, some type of a spitzer will work well.
The 155gr are a palma bullet and shoot past a 100 yards very well they carry a good BC
and have thin jackets so not a great bullet for hunting....
now you have my ....... .02

 

[Farmer Rob]

Hi guys,
Thanks for all your help so far. ( I noted i typed 100y on the title, but i meant 1000y)

I have been mucking around with size and powder and have settled on

165gn Sierra gameking as a multi purpose projectile.

With 42.5gn ar2206h (ADI powder) i am getting .645moa at 100y and still just under .9 at 450y (my longest distance at my current range).

So i have had a trigger job done and its now 2 lb, i have strengthened the fore stock to make sure i stay fully floated, added a bi-pod.

Now the next question is, what do i do next to bring it down some more?


Do i play with distance from lans, or crimping projectile or something else?

I mean, what will give me the best drop, because if my calcs work, .6@100, .9@450 so about 1.5@1000 by doubling my error, so thats 18 inches, on the card but could be better.

 

[submoa]

Re: Optimum weight for 100y, .308

well sounds like you need two loads use the 165 gamekings as a hunting load because they dont have the bc to go long range.

and a 168, 178 bthp match or a VLD of some sorts for targets 600 to 1000

 

[Farmer Rob]

Re: Optimum weight for 100y, .308

Submoa,

Please tell me what BC i need to accurately shoot 1000y. The GK hpbt are .363.

This is probably the things i really need to know and i suppose what my question really was, and i do guess your right that i need 2 loads, and since i will be adjusting the scope so far, a better bullet will reduce the amount i need to adjust.

 

[Lefty7mmstw]

Re: Optimum weight for 100y, .308

Submoa,

Please tell me what BC i need to accurately shoot 1000y. The GK hpbt are .363.

This is probably the things i really need to know and i suppose what my question really was, and i do guess your right that i need 2 loads, and since i will be adjusting the scope so far, a better bullet will reduce the amount i need to adjust.

A .363 BC is rather low for a long range bullet. I have shot deer at 700 yards with a .377 bc 7mm 140 grain pro-hunter though. The deer didn't give me guff that I had to low of a bc, and I suspect the target wouldn't either. It's really a matter of how much you want to raise and how much you'll be blown around by wind. I had 3500 fps on tap in a 7mm ultra. If you are shooting a 308, you don't have the extra velocity to get around using the best bc possible.

 

[Bart B]

Re: Optimum weight for 100y, .308

. . . what BC i need to accurately shoot 1000y. The GK hpbt are .363.

Any bullet with any BC well dimensioned, shaped and balanced shot at the same velocity across all of them will shoot sub MOA at 1000 when the wind's not blowing and the air's cool and stable so no outside force changes its trajectory. So one needs to get some wind-bucking ability to cut down wind drift from cross winds. Those with BC's above .490 do best that far away from 22 inch barrels leaving at least 2600 fps; Sierra's .308 175-gr HPMK for example.

While Palma (and the fullbore competitors around the world) shoot 147 to 155 grain bullets, they leave form 30 inch barrels to get the 3000+ fps needed to remain supersonic at 1000 yards. Barrels less than 28 inches typically won't do that with safe peak pressures. With your 22 inch barrel, either Sierra's 175's or Berger's 185's would be great through 1000 yards. Sierra's 168 never did well at 1000 from 22 inch barrels; they went supersonic around 900 yards. Sierra's 180 HPMK's now have that same boattail as the 168's and when that happened some years ago, their 180 HPMK's were never good at long range. The US Army had Sierra use their old tailing die to shape boattails like the original HPMK had and bought thousands of them to use in M14's. That original boattail was the same as 190's, 200's and 220 boattail HPMK's and outperformed the new ones quite handily.

 

[Farmer Rob]

Re: Optimum weight for 100y, .308

I know im going extreme her but since heavier bc is better and 185 bergers are better than 165 sierras because the berger's bc is .56 and the sierra's are .363

then is a 210 long range target berger at .626 better.

As mentioned before i have a 1in 10 twist but only a 22 bbl, will i handle a the 210's (berger say a 1 in 11 twist recomended)

Or even more, the berger website recomends a 230gn for a 1 in 10 at .743bc

So is heavier better???

Im going to take all your advice on board and make 2 loads so what should be my limit on the 1000 yarder be?

 

[Bart B]

Re: Optimum weight for 100y, .308

I suggest the Berger 185 over 42 grains of a powder equal to 4064's speed. That may keep the 185 supersonic through 1000 yards, but not much further. This is a maximum load so approach 42 grains from 39.

43 grains under a Sierra 175 HPMK is another choice but it is also a max load to work up to.

 

[ajhardle]

Re: Optimum weight for 100y, .308

I think Bart B might agree with me that most of the best 1000 yd loads are not magazine fed. I would load something in the 200 to 210 class out to the lands. It may infringe on case capacity, but these bullets are shaped so well for over 1k. Choose from 210 sierra mk, berger 200 gr hybrid or 210 vld, or the hornady 208 gr amax. My first choice would be a 200 hybrid, and if it shoots well, it will knock something like 20% off wind drift figures compared to a 175. Wind is the biggest challenge, so that is my priority in bullet choice.