Home Forums Reloading Big Game Rifles Question about 7mm08 ballistics

I leave for an Alaskan moose hunt in 3 weeks, and I finally found some ammo for my 7mm08 Kimber 84M Montana. My guide recommended 150 grain Barnes TTSX - it was impossible to find factory loads so I ordered 40 rounds from Choice Ammunition in Montana.

I shot 6 rounds today - 4 at 100 yards and 2 at 200 yards. Got it dead center at 100 so moved back 100 yards to 200. Fired 2 rounds and couldn’t even see them on the target! Walked 200 yards to check and found them dead center 5.5” below the bullseye. That seems like a huge drop from 100 to 200 yards.

My question: the barrel on my rifle is short at 19” due to a damage it suffered on a hunt in New Zealand that required it to be re-crowned. Is the 5.5” drop most likely from the decrease in velocity from the shorter barrel, or is it from the ammo? The ammo did not come with a ballistics chart like my factory ammo usually does.

I know nothing about this stuff so would appreciate any guidance. Do I need to worry about this drop or do I just aim higher at 200 yards and not shoot any further than that?

If I was you, I'd sight in at 200 yards and see how it looks at 100 yards and 300 yards and go from there. Or meters...something tells me you'd rather talk abut meters, but whatever.

Thank you. I should have added that the scope is a fixed 6x42 Leupold. I can barely see the target at 200 yards (slight exaggeration). This is my lightweight, rough weather mountain set up that I purchased for hunting in NZ when I lived there. I’m back home in South Carolina and shoot whitetail with a .270 win.

With a short time window, and limited ammo. You should consider taking your 270 moose hunting.

I would guess its a little of both. The shorter barrel will reduce velocity and the 150’s cant be moving all that fast. Did they give you any load data at all?

Why? My .270 is a beautiful Weatherby Mark V deluxe with a gorgeous stock. I’m don’t think the Alaska elements would be good for it.

Do you have an issue with the 7mm08 in general or with my bullet dropping 5.5” at 200 yards?

I would think hitting an Alaska moose would be like shooting the side of a small volkswagon. I"d sight that load in 3" high at 100 yds, it would be 2.5" low at 200, and go kill a moose with it. I'm sure the big drop is the loaded ammo and the short barrel combo. If it's accurate don't worry about it.

This.

I’d gun for 2.5” high at 100yds, but that’s not much different. Should keep midrange rise around 3” max. Fall in for a zero right around 200yds. Be about 10” low at 300,but I’d verify.

With a guide backing me up, I'd sight it 2.5 " high @ 100 yds also, but i'd keep my shots @ 200 yds or less with that cartridge, bullet and barrel length. Without a back up shooter i'd choose a bigger 7 and a 160 or 175 grn nosler partition or a good ol ought 6 with a 180 grn partition. [there are newer bullets that accomplish the same results] Remember the partition bullet was invented and the nosler company founded because of a bullet failure on a moose hunt!

Zero at 200 yards and hunt with confidence. I’ll be hunting moose this year with the same rifle and a 140 TTSX. I have zero doubts that it’ll work just fine.

The 150 TTSX will weigh more than a Partition after penetration, probably even a fair amount more than the 180.

I would be very concerned about using that ammo, sounds like it is loaded way light, I would definitely chrono it first.
You may well find it is too slow to get effective expansion
I would get some Nosler Partitions in your situation

Edit to add I just ran that drop thru JBM and it pencils out to about 2400 FPS

Even at 2400 fps MV, the bullet retains 1800+ fps out to over 300 m. If it were me, I might be getting concerned with the TSX, but not so much with the TTSX.

I would much rather a decent handload with the 140 like you are using, what speed are you getting.
Unfortunately that isn’t an option for the OP this late in the game

Part of the problem is the OP is sighting in dead on at 100 yards. The bullet can't go any higher and will only hit lower down range regardless of the distance. I load the 150 gr. Nosler Partition to 7-08 velocity and sight a 7x57 at 3" high at 100 yard. I'm good holding on hair to 300 and usually don't hat to shoot that far even on elk. So if I were the OP. I'd sight in 2.5 to 3.0" high and check where they hit out yonder.
Paul B.

Thank you all. I’m going to sight it in at 200 yards and report back.

200 yard zero will fix your troubles. Edk

This is what you need to do. For every inch you bump up the point of impact at 100 yards that will raise your point of impact 2” at 200 yards, 3” at 300 yards, etc. So bump up the point of impact to 2.5 to 2.75 “ hi at 100 yards so that will bring the point of impact up 5-5.5” or pretty much “on” at 200. Then around 8-9” low at 300 depending on exactly what your muzzle velocity is.

Yeah, exactly. I'm pushing the 140 TTSX to about 2800 fps in one load, and 2935 fps in another.