Home Forums Hunting & Shooting Hunting Rifles Load Development Results For My .308 - Low Velocity?

I tested some new loads yesterday for my .308 Winchester 70 Extreme Weather SS (22" barrel). The loads used Nosler cases, 150 gr. Hornady InterLocks and Varget. A chronograph was used about 12 feet from the muzzle. The results were as follows:


44.5 gr/2665 fps/1.475” group
45.0 gr/2670 fps/1.170” group
45.5 gr/2716 fps/0.606” group
46.0 gr/2727 fps/1.210” group
46.5 gr./2793 fps/1.295” group

Those are 4-shot groups. Clearly my rifle likes 45.5 grains. But the velocity seems lower than I'd expect from a 22" barrel, especially that 45.5 grain load. There are four possible explanations that I can think of:

1) I'm using an old Chrony chronograph; perhaps it's gone buggy.
2) The chronograph should have been farther out from the muzzle and perhaps I'm getting inconsistent readings that close.
3) It was a sunny day and while I was using the sun screens, maybe the sun was hitting the sensors and giving me inconsistent readings.
4) I'm obsessing over this too much. InterLocks tend to produce less pressure than some other bullets, and it is what it is. I should just live with what I've got.

I'm curious what you all think about this. Thanks!

Those really are more 165 gr/180 gr loads, not 150 gr loads.

IMO there is nothing wrong with your chrono, setup, etc. - those are velocities I'd expect to see.

My 308's generally run 165's with 46 gr's Varget for 2725 +/-, and the 150's with 47 gr's Varget for 2,825 fps +/- (22" bbl).

There's no problem running a 150 in the 2,700 fps range, depending on what you're using it for. It's just not a max load.

Yep. I was expecting to top out at something more like 2830 or thereabouts for 150s from a 22" barrel. Maybe I should try some at 47 grains and see what happens.

How many rounds down the barrel? Barrels usually pick up as much as 50-100 fps after about 150-200 rounds.

I usually put a screen-type chronograph around 10 ft. Never had a problem and I believe many published readings use 10ft, but at that range a bullet will only slow down about 10 fps anyway. If the results are erratic, perhaps the load is erratic as well. Odds are, the round will be effective further than you intend to shoot it anyway and the animal won't notice 100 fps.

Based on all the data you've presented, I'd absolutely load 47 gr's and expect around 2,830.

47.0 Varget with a 150 is a standard Hodgdon book load.

tylerw02, At this point, I'm probably getting a pretty close to 100 rounds through it, maybe a tad over 100.

Okay, Brad. That's good to know. I'll give 47.0 grains a whirl in the next batch.

This. Then I'd start working with the OAL as described here:https://bergerbullets.com/getting-the-best-precision-and-accuracy-from-vld-bullets-in-your-rifle/.


Okie John

Thanks, okie john!

Kiss,find pressure and rock on. Hint.

Pass the Alpha brass,Skinners and '17. Hint................

Do you have any leverevolution powder? That stuff churns out some of the highest velocities I've ever seen from the little 308 winchester.

An easy 2600 fps from 200 grainers, from a 22 inch barrel.

Good brass life.

Can get 2650 fps from a 200 grainer, but loose primer pockets after third firing:

https://www.24hourcampfire.com/ubbt.../308-win-200-grain-hotcor-leverevolution

That's fuggin bannanas.

I'm reasonably sure Winchester .308's have a long throat as Remington 700 .308's do. I tested factory 150 grain loads years ago in a Model 70 22" and got around 2750 fps. If you check how much jump to the lands, that will tell you whether the throat is excessive. If the throat is long, you will probably be able to go to 47 grains Varget for around 2830 as previously stated.

Your load of 45.5gr will do anything that rifle & bullet need to be doing.

Riflehunter, I know that's true, at least in my rifle. With those bullets, a 2.844” COAL has the bullet touching the lands. I loaded them at 2.804" (.040” off the lands). And I'm still about 1/8" from the cannelure. What you said makes sense. I'll try 47.0 grains and see what I get. Thanks!

Tyrone, I know you're right, but if I take the gun out west at some point, as I intend, an extra 100 fps wouldn't hurt.

My 700 .308 gets fed a steady diet of 150g Hornady Interlocks. 45.5g of Varget in my 22" barrel gives me a velocity of 2,787FPS.

I wouldn't sweat it.

Are your accuracy figures from a single group, or an average of several? A single group might not give a true picture. The other groups were so consistent that I’d wonder if the 0.6 group is repeatable. If it is, I’d shoot that one. BTW, Hodgdon’s site shows a max charge of 47.0. This would likely give 2800+.

WMR,
Those are initial groups. I loaded four of each for initial testing, just to see what I got. Now I intend to go back and shoot two four-shot groups each of 45.5, 46.0, 46.5, and 47.0, to see if they're repeatable. At that point, I should have an idea of what's consistent. After that, I'll start playing with seating depth with the best load. That's the plan anyway.

Im doing or was doing some load development with 150's and varget. 155 Scenars.

43 gr was 2650
44 gr was 2715
45 gr showed dupl on my screen
46 gr showed 2760

Underwhelming. A blue box Federal 150 then went across the screens at 2807. How's that for a kick in the pants? I don't know about you but I reload to do better than factory ammo available on the shelf at Walmart for 24.97 a box.

So I loaded up with TAC and at 45.5 gr I am averaging 2860 which is more like it.