.308 16" 1:10 where to start?!

[Nomadarmy]

I'm not new to re-loading I used to do it all the time when I was stationed in Hawaii for .223 as brass was easy to get.

I got a killer deal Saturday on a DRD Paratus P762 (Gen2) ($1600) I just couldn't pass on it, such a cool concept and great price....anyway I really want to maximizes the effectiveness of the rifle and push it to it's limits.

Where should I start with loads? IMR 4064, 175 grain? In the future I will be adding a Suppressor to it -


pics of my 3 Guns I got during Black Friday deals:

1. DRD Paratus P762 (Gen2) $1600
2. Ruger SR-556 “Takedown” $700
3. Sig Sauer 556 DMR $800

The DRD Paratus Assembled:

 

[JBT47]

4064 works with 175’s. So does Varget. If using Varget and 175’s start around 40-41gr and work up.

 

[GaryL1959]

I'm not new to re-loading I used to do it all the time when I was stationed in Hawaii for .223 as brass was easy to get.

I got a killer deal Saturday on a DRD Paratus P762 (Gen2) ($1600) I just couldn't pass on it, such a cool concept and great price....anyway I really want to maximizes the effectiveness of the rifle and push it to it's limits.

Where should I start with loads? IMR 4064, 175 grain? In the future I will be adding a Suppressor to it -


pics of my 3 Guns I got during Black Friday deals:

1. DRD Paratus P762 (Gen2) $1600
2. Ruger SR-556 “Takedown” $700
3. Sig Sauer 556 DMR $800

The DRD Paratus Assembled:

Start with the suppressor....a 16 inch .308 is an ear blaster...

 

[Kurz]

If you're intent on using the 175 grain bullets then you will be looking at:

AR COMP (41 is the top of the pressure curve)
CFE223 (check with Hodgdon, they say start is 45.5)
IMR-3031 (41 is top of the pressure curve)

All three of these powders yielded the highest velocities combines with accuracy.

Regards.

 

[gsg5pk]

My Pet Load
43.0 gr. of 4064
175 SMK COAL 2.800"

 

[Rstrick0352]

You’ll never get the velocity from that short of a barrel to wring out the BC the 175s are capable of. Stick to a 155gr and scrounge up all the velocity you can get with some CFE223 and take advantage of a flatter trajectory and similar max effective range. Either way you go, 800ish meters is about as good as you can expect from the short barrel. Don’t get me wrong, I’m not knocking short barrels, I have two 16” .308s. I’ve just been shooting them long enough to make pragmatic judgements on their capabilities. Good luck!

 

[Zero333]

308win Gas guns don't like pressures over 55,000 psi unlike bolt guns that take 62,000 no problem.

I would work around 42.5 gr of 4064 with 175 grainers and 43.5gr with 168's.

H-4895 and IMR-4895 are 2 very good 308win gas gun powders IMO.
41.5 gr H/IMR-4895 with 168's and 40.5 gr with 175 grainers.

 

[ImBIllT]

Velocity degrades, BC is forever. High BC bullets are just fine in short barrels.

 

[Depart123]

Even with the 16" barrel, it is still a 700 yard gun. I don't know what else you could ask from a package that compact.

Loads that have worked well in AR's for me. as well as M1A's for others are:
43 gr 4064
43-43.5 gr Varget
39.5 gr 3031

175 gr SMK, 2.75-2.8" C.O.L. in LC Brass.

 

[Rstrick0352]

Velocity degrades, BC is forever. High BC bullets are just fine in short barrels.

That's not accurate at all, BC is velocity dependent. There are 155's out there that he can load to mag length and nearly match the 175 for BC, at a much healthier dose of velocity than a 175gr SMK, which is the bullet I feel like the OP was alluding to. Also, I absolutely agree with you the high BC projos are fine in short barrels. What I said was heavy bullets that can't be driven to their potential out of a short barrel should be reconsidered.

 

[ImBIllT]

Berger offeres four different 175gr bullets. There is no reason to assume he is speaking of the SMK. Although, three of the four have lower form factors than your top Palma bullets, you must consider that muzzle velocity is dependent upon ACCELERATION. The short barrel robs many more FPS from the light bullet than the heavy bullet. He will experience less wind drift shooting a 175gr Berger than he will shooting a 155gr Berger. Only one post actually mentioned range. Yes, he will be limited by the maximum range at which he can keep a bullet above transonic region.....unless he shoots a transonically stable bullet...and those do exist in .30cal.

 

[Rstrick0352]

Berger offeres four different 175gr bullets. There is no reason to assume he is speaking of the SMK. Although, three of the four have lower form factors than your top Palma bullets, you must consider that muzzle velocity is dependent upon ACCELERATION. The short barrel robs many more FPS from the light bullet than the heavy bullet. He will experience less wind drift shooting a 175gr Berger than he will shooting a 155gr Berger. Only one post actually mentioned range. Yes, he will be limited by the maximum range at which he can keep a bullet above transonic region.....unless he shoots a transonically stable bullet...and those do exist in .30cal.

Just ran the numbers to humor myself using the Berger 175 tactical and the Berger 155 Hybrid. The velocities are reasonably achieved by both. Results are at 700m and a 10mph wind.

-175gr@2600fps= 7.01mils elevation/1.93mils of wind/1447fps remaining velocity
-155gr@2700fps= 6.59mils elevation/1.94mils of wind/1472fps remaining velocity

I know that isn't every possible projectile but they are some of the best examples you can get for reliable gas gun performance and the numbers speak for themselves. As a matter of fact, they say exactly what I said in my first post... Under most circumstances, he'll enjoy flatter trajectory and similar wind defeating ability with a 155 over a 175.

 

[Depart123]

... Under most circumstances, he'll enjoy flatter trajectory and similar wind defeating ability with a 155 over a 175.

If he can get the pointier 155's to group in his gun. In my experience 175's are much more forgiving of different chambers and lead angles. They just have more bearing surface to guide it into the lands straight. The most forgiving 308 cal bullet in the world is the 168 SMK. It's a dog ballistically, but it's the rare gun that won't shoot it and it will still get to 600 -700 yds without going to hell.

 

[Rstrick0352]

If he can get the pointier 155's to group in his gun. In my experience 175's are much more forgiving of different chambers and lead angles. They just have more bearing surface to guide it into the lands straight. The most forgiving 308 cal bullet in the world is the 168 SMK. It's a dog ballistically, but it's the rare gun that won't shoot it and it will still get to 600 -700 yds without going to hell.

Great point on the 168 and its ability to perform within the ranges a 16" barreled gun will realistically run. Your comment on the pointy 155's is not lost on me however, I have found the 155 Scenars to be quite forgiving and very capable in my gas gun.

 

[ImBIllT]

Just ran the numbers to humor myself using the Berger 175 tactical and the Berger 155 Hybrid. The velocities are reasonably achieved by both. Results are at 700m and a 10mph wind.

-175gr@2600fps= 7.01mils elevation/1.93mils of wind/1447fps remaining velocity
-155gr@2700fps= 6.59mils elevation/1.94mils of wind/1472fps remaining velocity

I know that isn't every possible projectile but they are some of the best examples you can get for reliable gas gun performance and the numbers speak for themselves. As a matter of fact, they say exactly what I said in my first post... Under most circumstances, he'll enjoy flatter trajectory and similar wind defeating ability with a 155 over a 175.

So the 175 OTM had less wind drift, and more momentum. It also has more velocity at 900yds and 1000yds than the 155 Hybrid, meaning that 1000yds is possible at lower elevations and temperatures than with the 155 Hybrid. A short barrel may handicap a cartridges capabilities, but you have not proven that it relegates it to light bullets.

The purpose dictates the bullet a lot more than the barrel length does. For unknown range hunting, I would shoot the 155VLD. The flatter trajectory reduces the cost of ranging error, and at hunting ranges the wind drift difference is negligible. For known distance target shooting the 168 SMK is definitely tempting at close to mid range. The 215 Hybrid at 2400fps is good to 1000yds under most conditions(not quite sea level and 60 degrees) and has 25" less wind drift than the 175 OTM at 2600fps and 29" less wind drift than the 155Hybrid at 2700fps.

 

[fyrewall]

That sure is an impressive rifle. The .308W will work with probably 1000's of combinations of bullets and powder. I have 2, .308's and use them to burn up various powder remnants like AR-Comp, W748, 2000MR, Varget, Re15, R-S TAC that I use in other rifles. Some times out at the range I have a box of 50 loaded with 3-4 different powders and there does not seem to be much difference and is fun to play around with while I shoot up the whole box. During the past component emergency I used the old and almost forgotten IMR 4320 with good results.

On selecting a bullet consider what the objective will be. Most of my experience with .308's has been at 200 to 600 yards using 168's both Hornady & Sierra. I shoot mostly 155's now because they offer relatively flat trajectory with velocities above 2,800 fps in my 22 -23 inch barrel bolt guns. An item to consider is drag factor vs. ballistic coefficients or to compare 2 bullets both having near drag factors but different weights and having different velocities, the lighter of the two being able to be driven faster. The Berger manual & Hornady 4DF calculator gets into this.

I also have fun shooting 125 Hornady SST's up to 300 yards, the MV is just around 3000 fps. I like IMR 8208 for this.

 

[Rstrick0352]

So the 175 OTM had less wind drift, and more momentum. It also has more velocity at 900yds and 1000yds than the 155 Hybrid, meaning that 1000yds is possible at lower elevations and temperatures than with the 155 Hybrid. A short barrel may handicap a cartridges capabilities, but you have not proven that it relegates it to light bullets.

The purpose dictates the bullet a lot more than the barrel length does. For unknown range hunting, I would shoot the 155VLD. The flatter trajectory reduces the cost of ranging error, and at hunting ranges the wind drift difference is negligible. For known distance target shooting the 168 SMK is definitely tempting at close to mid range. The 215 Hybrid at 2400fps is good to 1000yds under most conditions(not quite sea level and 60 degrees) and has 25" less wind drift than the 175 OTM at 2600fps and 29" less wind drift than the 155Hybrid at 2700fps.

Dude, I'm not doubting you on the merits of heavier bullets when possible. The guy is shooting a 16" barreled gas gun and every projectile you've recently spoke of generally cant be used in a magazine and that is the point I'm trying to make. You're reaching right now to save you from your completely incorrect statement about how BC is forever. The 175 beat the 155 in my example by a hundredth of a MIL in wind defeating while the 155 handily beat it in drop. Please continue trying to dig yourself out of a hole by citing very specific circumstances where certain load combinations may beat the general advice I originally provided the OP, which will work under most circumstances.

 

[ImBIllT]

Dude, I'm not doubting you on the merits of heavier bullets when possible. The guy is shooting a 16" barreled gas gun and every projectile you've recently spoke of generally cant be used in a magazine and that is the point I'm trying to make. You're reaching right now to save you from your completely incorrect statement about how BC is forever. The 175 beat the 155 in my example by a hundredth of a MIL in wind defeating while the 155 handily beat it in drop. Please continue trying to dig yourself out of a hole by citing very specific circumstances where certain load combinations may beat the general advice I originally provided the OP, which will work under most circumstances.

The magazine is a much more limiting factor than the barrel length. The 16" barrel does not prevent him from shooting any of those bullets. I shoot 190 VLD's from a magazine.