2 accuracy nodes

[rebs]

I am shooting under 1 inch groups with everything the same except the powder charge at 100 yds. Same cases, same bullet and same primer. The first node is 23.4 of H335 and the second node is 25.3 of H335.
Will the larger powder charge be any flatter shooting at longer ranges ? Is there a benefit to loading the larger charge ?

 

[RC20]

What are you shooting?

Faster velocity will equal a flatter trajectory.

If its a mortar round though, not a lot.

Keep in mind, flat trajectory is relevant out to maybe 350 yards, after that you are shooting above the hopped for POI 6 -10 inches with most rifles.

I am not sure what flatter means when you get out to 1000 yards+

Less powder does equate to less barrel wear (throat) so as little as you can get away with is always better in that regard.

Barrel burners (243, 300 wm even more so)

Sniper kills at 2500 yards? That's just luck. The skill is there in assessing it, but at those ranges, far more misses than hits.

 

[rebs]

I am shooting 55 gr hand loads in my AR with a 16 inch barrel 1 in 8 twist.

 

[Stats Shooter]

Less powder does equate to less barrel wear (throat) so as little as you can get away with is always better in that regard

Yes and no. Throat erosion does correlate with more powder...But it is accelerated by overbore cartridges forcing a lot of gas through a small opening (relatively).

A 30-06 uses more powder than a 243, but 243 is much harder on barrels. Then there is the powder burn rate...More RL 25 than RL15 may not mean more throat erosion.

But in a .223 REM, throat erosion happens relatively slowly so if I were you, I would use the highest velocity accurate load that is safe.

 

[Don Fischer]

Could ya define harder on barrel's?

 

[Snyper]

Could ya define harder on barrel's?

He's saying it will erode the barrel more rapidly.

 

[Stats Shooter]

What I meant was that the throat erodes faster. Here is a nice article on throat wear.

Barrel burners actually damage only the first few inches in front of the chamber...The reminder of the barrel will still look mostly new by the time you wear out the throat.

 

[rebs]

Thanks for the replies I appreciate it.

 

[std7mag]

It's fairly common for me to find 2 accuracy nodes when I'm working up for a powder/bullet combo.
1 down where my start is, the 2nd closer to max load.
This has been commented on by several others also.

When I'm planning on doing a lot of range shooting, I load to the lower node. Saves some powder, less recoil, a little easier on the barrel.

Hunting, I load to the higher node. Although any critter is sure not to notice the difference, just piece of mind to me.

 

[Unclenick]

As already mentioned, multiple accuracy nodes are common. Yours being about 8% apart in powder charge weight is also pretty typical spacing, though nodes separated by half that much difference are sometimes found.

If one node makes smaller groups than the other, use that one. If they are the same, use a chronograph to see which one produces a lower SD and use that one, as it will string less at longer ranges.

Being flatter shooting has very limited practical value in this context, especially if you are shooting a flat base, low BC bullet. If you zeroed both loads at 200 yards, the faster bullet would hit about .3" lower at 125 yards, which is near where the arc of the trajectory peaks, and would carry a -4" drop (a common lower kill zone number) about 5 yards further out to about 255 instead of about 250 yards. Note that this is based on guesses of your velocities based on the Hodgdon velocities with an allowance for your barrel being 16" and theirs being 24".

 

[Jimro]

With a 55gr bullet from an AR there really isn't much need to use the heavier powder charge to get to that accuracy node. 55gr bullets just aren't that great for long range shooting, they were originally intended to give the M16A1 a 250 meter "battlesight zero" which is why there the M16A1 had to adjust for drop with the front sight post since there was no rear adjustment.

However, 25.3 gr of H335 is Hodgdon's listed max, with 3,200 fps from a 24" barrel. That's still a bit shy of the M193 load which was a tad faster than that from a 20" barrel. So my recommendation is to use the 23.4 gr charge for the following reasons.

A 55gr FMJ at 2,850 fps will have 5.1 minutes of drop at 300.
A 55gr FMJ at 3,050 fps will have 4.4 minutes of drop at 300.

These velocity numbers are my estimate based on your barrel length and powder charge, but essentially 200 fps is pretty standard for the close to starting and max charge for H335.

That means the extra 1.9gr of powder buys you a massive 0.7 MOA of "flatter shooting" which translates into 2.1 whole inches at 300 yards. So no need to waste the extra powder in my opinion.

Jimro

 

[rebs]

Thank you guys, I will use the 23.4 load.