Thread: 308 Short Barrel Ammo Advice

Originally Posted by Pommy

I've punched the numbers into Strelok. With a 100m zero, the absolute drop in inches at 300m is right around 31 inches with an MV of about 2800. Or about 5.5 MOA. Sounds pretty normal so far. What does it group like at that distance? If it's dropped 31" from your 100m POI, yeah, that ain't right.

Factory ammo is always a bit of a gamble. You could get lucky and find the cheap stuff shoots amazingly. If not, you might have to try a selection premium stuff. Chances are at least one will shoot well. But still there's no guarantees.

Seems to group alright, at least well enough for me anyway. Yeah it has dropped 31inchs form the 100m POI. It seems odd that it looses so much FPS and drops so much. Just wondering what the thoughts on that are

That seems a lot of drop, very slow....your rifle may have generous chamber dimensions dropping pressure and speed perhaps.
Handloading for it would be the go ideally but maybe trying some hornady superfomance might get the speed up and lessen the drop.
Also zero at 200 if not dialing up scope.

ok I m going to have to poke some numbers in to have a look myself..... Im thinking its the 100yard zero is issue....
hold the line caller.

2100 if you half inch low at hundy........you would need to be closer to 3" low at hundy to get 30 low with 2800fps.

Originally Posted by Micky Duck

2100 if you half inch low at hundy........you would need to be closer to 3" low at hundy to get 30 low with 2800fps.

Cheers Micky, Ill do a bit more testing and try some superformance see where that gets me. Hopefully a change in ammo will see me right!

DONT DO IT......... or be careful if you do.....mates brand new sako really didnt like it...blown primers and harsh recoil.... but maybe you have generous chamber and loose bore causing low velocity from the fusion..so it may be ideal.....

.414 is advertised BC if anyone else cares to punch numbers...took a bit of digging to find it LOL.

Originally Posted by Micky Duck

DONT DO IT......... or be careful if you do.....mates brand new sako really didnt like it...blown primers and harsh recoil.... but maybe you have generous chamber and loose bore causing low velocity from the fusion..so it may be ideal.....

If other ammunition has the same problem leaning towards a loose bore issue can cause other issues?

My Bergara I think from memory was 2650(?) with the 18 inch factory barrel federal blue box . Is the 2850 the factory speed with a 22(?) inch barrel ?
So not going as fast , more drop.?

Greetings @Jim356,
My 20 inch barrel in .308 delivers 2,750 fps with my handloads which should work out to 2,700 fps in an 18 inch barrel which is not all that short. You really need to chronograph the load to see what you are actually getting. The chronograph will tell you if it is a slow load or not. If it is slow, say under 2,600 fps, chronographing the load in another .308 will tell you if it is a load problem or a rifle problem. My guess would be a scope problem or perhaps different holds used at the two ranges. Chronographing will narrow down the problem to the actual cause. When testing everything needs to be the same. Same position, same hold, scope power unchanged and preferably same day and conditions. Otherwise you learn nothing.
Lastly a plug for handloading. Using factory ammo leaves us at the mercy of the manufacturers. Some ammo is good most of the time, some good some of the time and some no good whatsoever. Taking charge of this variability via loading your own gives you much more confidence in the ammo that you shoot.
Regards and best of luck Grandpamac.

right...so IF your velocity IS INDEED only 2100fps...sight in 3" high at hundy...dead on 3" high..you will be 2" low at 200yards....
but that seems really slow...highland/ppu slow.....
loose chamber/bore no real issue once you reload as you will grow cases to be more snug fit and will be able to up powder charge accordingly untill velocity gets more in line with what you want...apparently some barrels are just slow....chuck chronicgraph into mix and some folks get really depressed about it....not me,velocity matter not a bit to me....most of my shots under 200 yards.

Originally Posted by grandpamac

Greetings @Jim356,
My 20 inch barrel in .308 delivers 2,750 fps with my handloads which should work out to 2,700 fps in an 18 inch barrel which is not all that short. You really need to chronograph the load to see what you are actually getting. The chronograph will tell you if it is a slow load or not. If it is slow, say under 2,600 fps, chronographing the load in another .308 will tell you if it is a load problem or a rifle problem. My guess would be a scope problem or perhaps different holds used at the two ranges. Chronographing will narrow down the problem to the actual cause. When testing everything needs to be the same. Same position, same hold, scope power unchanged and preferably same day and conditions. Otherwise you learn nothing.
Lastly a plug for handloading. Using factory ammo leaves us at the mercy of the manufacturers. Some ammo is good most of the time, some good some of the time and some no good whatsoever. Taking charge of this variability via loading your own gives you much more confidence in the ammo that you shoot.
Regards and best of luck Grandpamac.

Cheers for that. Have always been interested in reloading but never taken the jump mainly considering due to my circumstances limiting that ability. Will try something else and really make sure my variables are correct and see what happens! Thanks All!

Originally Posted by Chunk

My Bergara I think from memory was 2650(?) with the 18 inch factory barrel federal blue box . Is the 2850 the factory speed with a 22(?) inch barrel ?
So not going as fast , more drop.?

Federal claim 2820fps from a 24" barrel. I chrono'd it in a Remington 700 22" barrel at just on 2800fps so was happy enough with that.

Right quick update, I managed to get into town and pick up some ammo. I ended up grabbing some Hornady American Whitetail 165gr just to see how it went. RE-checked zero and shot a few groups to see how it would go. The rifle didn't think much of it with the best group being 3inches, with the fusion shot miles better interms of grouping. Thought bugger it I'll have a few shots at 300yards to see what it would do. Grouped poorly as to be expected based on the 100 yard grouping, and ended up with 24inchs average drop form my 100 POI once again going through the same system as last time its about 2200fps.

Now correct me if I'm wrong but I am shooting a heavier projectile that is already going 110fps slower than the fusion based on the factory testing would it not be inclined to have more drop than the fusion at 300m?

I am still waiting to get my hands a chronograph which will give me a more defiant answer but just though I'd see what everyones thought are on that. On a side note I have done this system to find my FPS/Drop for 2 other rifles with good success.

For anyone interested my scope is a Swarovski Z3 4-12x50bt with bases been correctly torqued.

Originally Posted by mimms2

You're asking about "internal ballistics" which is approximately equal to "voodoo" as it is generally only inferred from down-range results.

Anyone that tells you otherwise can either measure the frequency of the moon on a tuesday in 193-12, or is bullshitting you.

If you have the means (a hammer-puller and a seating die) - throw the factory projos, find the lands with them, and re-seat to 20-thou off that and see if it doesn't pull itself into line.

Consider that factory ammo has to be safe in -all- rifles, and american ammo in particular is *lawyer*-safe in all rifles.

Also, drop charts and calculations (and especially guessing at velocity) is only good in-theory, and ALL must be verified (D.O.P.Ed) at the ranges you're intending to shoot.

Alway been planning on getting into reloading and now seems like the right time to take the jump and see what happens.