Quest for the right ammo.

[Kodiak19550]

Hi all, I'm a newbie to this forum and a newbie to the world of suppressors, I've jumped in with a Savage .308 model 11 bolt action Integrally Suppressed, 20" barrel , my primary use will be to pick off hogs at 100 yd , I'm on a quest to find out what ammo my gun likes best, I believe the twist is 1-10 not sure about that ,so I picked up a couple of boxes of Sellier & Bellot 200 grn. HBPT 7,62 x 51 subsonic, at 100 yd there was no keyhole but the drop was considerable (16") from 75 yd where I was an inch high from zero, that much drop scared the hell out of me , now I'm thinking I need to start going down in grains to get a flatter trajectory, does that sound like I'm thinking in the right direction here ? Any suggestions , because I'm scratching my head on this one.

[johndoe3]

Your thinking is correct, you don't need a heavy bullet for hogs. After all, many people are using 300 Black for hogs with 125gr or 135 gr bullets going only 2100-2300 fps.

Your 308 can be a laser with a 130 grain good hunting bullet...like these

https://www.midwayusa.com/product/95718 ... -box-of-20

3125 fps in your rifle--a laser instead of rainbow trajectory (2818 ft lbs with Barnes Tipped TSX bullet, lead free).

Look around, these are great rounds but pricey (reasonable if you reloaded).

[fishman]

It's unclear if you're suggesting trying lighter subsonic bullets or supersonic bullets. The weight of the bullet has no effect on trajectory, the speed does. So any subsonic bullet will have a crappy trajectory.

Any supersonic bullet will have a better trajectory, it doesn't have to be a lighter bullet, just faster.

If you want quiet subs, you'll have to deal with the trajectory. If you want a flat trajectory, your gonna have to go supersonic and deal with the loud crack of the bullet.

[Kodiak19550]

Thanks ,I appreciate the answers, I'm looking for subsonic rounds only, I was just really surprised at the amount of drop at the 100 yd mark, so the heavier grain produces a quieter shot ? wow, I was thinking it was the opposite.

[doubloon]

Thanks ,I appreciate the answers, I'm looking for subsonic rounds only, I was just really surprised at the amount of drop at the 100 yd mark, so the heavier grain produces a quieter shot ? wow, I was thinking it was the opposite.

It's the slower velocity and less outgassing that produces a quieter shot. Lighter bullet can be subsonic too. Some light reading on subsonic http://www.fieldandstream.com/articles/ ... cartridges

Subsonic 308 rounds can be loaded with 150gr bullets but they won't transfer as much energy on the target as a subsonic 200gr bullet. Also, a subsonic 150gr bullet and a subsonic 200gr bullet will have a similar trajectory. Similar meaning a lot of drop but the 150gr bullet will drop even more than the 200gr bullet. The reason for this is they are moving at the same speed ... subsonic ... but the heavier bullet will maintain more forward momentum ... that Newton guy really knew his apples.

Think whiffle ball and softball. Throw a whiffle ball 70mph vs throw a softball 70mph. They'll both travel the first foot or two at about the same speed on about the same trajectory but 10 feet out the whiffle ball slows down faster and drops faster. The softball will do more damage than the whiffle ball anywhere along the trajectory and especially at 20ft.

... my primary use will be to pick off hogs at 100 yd , I'm on a quest to find out what ammo my gun likes best, ...

Yes, your factory barrel is 1:10 which is plenty to stabilize heavier bullets like 200gr+.

Like John says, if you're restricting yourself to off the shelf ammo there tends to be a direct correlation between bullet weight, muzzle velocity and trajectory. Without getting into the details of loading data lighter bullets generally always travel faster and shoot flatter when it comes to OTS ammo.

Be aware when you go down in weight and up in velocity you will, at some point, pick up the sonic crack and no longer be as quiet as a subsonic round.

There is nothing wrong with a large drop in trajectory as long as it's repeatable and consistent. A bullet with an arc like the the my little pony rainbow can still be more accurate than a bullet that shoots as flat as Kiera Knightly. When you say the bullet drop was 16" when you were aimed 1" high from zero remember that was 1" high from zero with faster moving ammo. That hole 17" below your point of aim is actually "zero" for that slower moving ammo. You can't zero your gun with one load specification and expect it to be zeroed for every load. This link does an OK job of explaining the basic concepts of external ballistics. http://www.rifleshootermag.com/shooting ... or-dummies

What ammo your gun "likes best" (most accurate) depends on a lot of things but muzzle velocity and trajectory aren't necessarily the most significant. I can pick up a half dozen boxes of 168gr 308 with similar velocities from different manufacturers and they will all shoot different from my gun. One or two will print a tight pattern and probably half or more will make the target look (to my eye) like I was using a shotgun but still be plenty accurate enough for a hog. Bullet shape, seating depth, burn rate, OAL, yada yada, blah blah all have an effect on the accuracy of the round in any given gun. And some guns are more forgiving when it comes to ammo than others.

[Kodiak19550]

Doubloon, I really appreciate your explaining of the subsonic ballistics, that clears up quite a bit of the mystery, especially the wiffle ball analogy , I found a 175 gr Sub. from Atomic that velocity is 1050 fps, as opposed to about 990 from the 200 gr I'm using, I'll play with that for awhile, I think just rapping my head around what to expect from subsonic loads is a tremendous thing, I'll checkout those links and keep tinkering with different ammo not only to get it right but because I enjoy the process anyway, thanks again.

[fishman]

Doubloon, I really appreciate your explaining of the subsonic ballistics, that clears up quite a bit of the mystery, especially the wiffle ball analogy , I found a 175 gr Sub. from Atomic that velocity is 1050 fps, as opposed to about 990 from the 200 gr I'm using, I think just rapping my head around what to expect from subsonic loads is a tremendous thing, I'll checkout those links and keep tinkering with different ammo not only to get it right but because I enjoy the process anyway, thanks again.

A 308 can definitely push a 200 grain bullet 1050. Even 300 blackout can push a 230 grain bullet that speed below max load

[doubloon]

... I found a 175 gr Sub. from Atomic that velocity is 1050 fps, as opposed to about 990 from the 200 gr ...

All well and good.

Google some ballistic calculators like this one at Hornady http://www.hornady.com/ballistics-resou ... calculator

Pretending they have the same ballistic coefficient (because at 100 yards who cares) a 175gr bullet starting at ~1050 fps will be moving ~1000 and dump ~390ft-lb of energy into the target where the 200gr bullet starting at 990fps will be traveling ~945fps when it reaches the target and dump ~400ft-lb of energy into the target.

Heavier things tend to hold there speed and momentum longer, that apple guy again, not Steve.

The drop difference between those two loads is negligible at 100 yards, maybe 1/2", and won't matter to Arnold. If you're seeing a 16" difference between a standard velocity load and a subsonic load at 100 yards it seems (to me) more likely to be caused by POI shift from the suppressor. Try shooting both standard velocity and subsonic both suppressed and unsuppressed and see if you get a big POI shift between suppressed and unsuppressed with both loads.