7-08 / Big Game

[Don Fischer]

Funny. I've read about ladder test's a bunch of time's and have tried them a bunch of time's. Never got a thing out of them that made any sense at all to me! Must be missing something but never figured out what. I suspect that my problem may be how I work up load's has worked for me for years and I don't take change easy!

 

[HiMtnHntr]

I tried a few ladder tests. I think they work well for determining what charge ranges produce best accuracy, and it's also an efficient way to test different charges for safety purposes.

 

[Beanland_fan]

What was the velocity data?

I use Big Game with 140 accubond in my 7mm08, with 22.5” barrel.
Nosler brass, TULA LRM primers.
46.5 grains got me 2,850
47.0 resulted in 2,890
I stopped there because it was very good accuracy.

 

[Brian in Montana]

So the final result from the previously mentioned ladder test (barring a tweak here or there) is 46.8grns of Ramshot Big Game, 140grn Nosler Accubond, Fed 210M primers - a 5 shot group .8 inches at 100yds. Average MV = 2868fps. Extreme spread = 28. Standard Deviation = 10.

Thats probably not bad for a guy of my experience level with hand loading, but I was hoping the ES and SD would be a little lower. That does seem to be about the best I can do on most loads.

 

[Beanland_fan]

You might try the 215M primers also

 

[std7mag]

That's tooling along pretty good there!
My Stevens 200 in 7mm-08AI would get 2,916fps but only with RL17.
I should note that this was it's accuracy node.
All the other powders tested netted 2,836fps. Again accuracy node.
I really wish Big Game was more available in my area.
Still keep looking, have only seen it on a shelf once.

 

[Brian in Montana]

My 7-08 sure does seem to like Big Game. It is kind of hard to find. I'm going to need some more soon and I have noticed its not on the shelves all that much.

 

[blueridge]

My 7-08 sure does seem to like Big Game

Have you tested it with 150gr bullets or just 140's? I am wondering if I should buy a pound to test with for 150gr E-Tips (it's not listed on Nosler's load data for the 150).
I've gotten good results with RL17 and 140gr TTSX, but I would prefer to use the heavier bullet for elk, and would like to get greater than 2688fps that I am getting with H380. Wondering if Big Game could be the answer.

 

[huronmtns]

I believe you will exceed your velocity with the H380 powder you have listed. One factor may be your bullet seating depth and case fill. Big Game uses a lot of case capacity and has compressed loads. I pulled this info from the western powder manual for the 7mm-08. This should give you a better idea toward your goal. My experience with Big Game in my 7mm-08 reloading is it will give you great velocity but can have slightly higher extreme velocity spreads than other powders.

 

[blueridge]

thanks for sharing that. looks like I'm not far from max velocity as is, ~40fps under what's listed for BG. i may stay with what I have then and see if a primer change can make up the difference.

 

[Brian in Montana]

I have a box of 150gn ELD-X that I couldn't get to shoot worth a darn with Varget, H4895, or H4350. I might try those with BG at some point. I'm really more interested in lighter bullets and speed with this rifle, though. I'm mainly planning to use it for deer/antelope sized game and just shooting. I have a couple good loads using various combos of H4895, Varget, 139gn Hndy BTSP's and Accubonds. The one with Big Game is certainly the best I've worked up.

I noticed last night that Midway USA has 139grn Hndy Interbonds available. I'm tempted to get a box of those and give them a try with Big Game.

 

[Ajax2744]

Sorry for the ignorance but what is ladder testing? I have actually never heard of it till this thread and what is the goal you're trying to accomplish with it?

 

[Brian in Montana]

There's a couple different ways to do a ladder test, but the idea in a nutshell is to identify potential accuracy nodes in the first step of the load development process. I'm sure someone else could probably answer this question better than I can. I've only just started using it.

If you're interested, try 6.5 Guys on YouTube. They have a few vids on ladder testing I found very informative. I (basically) use their version of the ladder test with a magnetospeed chronograph.

 

[std7mag]

Ajax,
As mentioned, there are several ways to do it.
1) load up 10, (or 20 or whatever you feel it takes) going up 0.3 gr of powder for each round. Shoot over chrono and look for flat spots in you velocities.
2) (the way i do mine) load 10 rounds going up 0.3 gr of powder each round. Shoot target, keeping track of impacts. Your looking for 3 closest together vertically.
Middle # shot on those 3 is your powder charge.
These tell you what your barrel likes.
When done with that, play with seating depth off the lands looking for tightest grouping. This tells you what the bullet likes.

If you have a Savage, ( i don't know why it wouldn't work for other makes) you tune your action, by shooting groups while adjusting the torque on your action screws.

Some people shoot groups while doing powder charge testing. In my opinion not telling them a darn thing.

 

[BuzzH]

Have you tested it with 150gr bullets or just 140's? I am wondering if I should buy a pound to test with for 150gr E-Tips (it's not listed on Nosler's load data for the 150).
I've gotten good results with RL17 and 140gr TTSX, but I would prefer to use the heavier bullet for elk, and would like to get greater than 2688fps that I am getting with H380. Wondering if Big Game could be the answer.

If it were me, I wouldn't worry about using a 140 on elk, that extra 10 grains of bullet weight, jumping to a 150, isn't going to gain you much in the way of results on elk. Since velocity is an issue with the all copper bullets, I would strongly consider staying with the 140 ttsx and get all you can velocity wise. IME, getting 2850-2900 with a 140 isn't that tough, and a good place to be with an all copper I would think.

 

[JLS]

If it were me, I wouldn't worry about using a 140 on elk, that extra 10 grains of bullet weight, jumping to a 150, isn't going to gain you much in the way of results on elk. Since velocity is an issue with the all copper bullets, I would strongly consider staying with the 140 ttsx and get all you can velocity wise. IME, getting 2850-2900 with a 140 isn't that tough, and a good place to be with an all copper I would think.

I agree 110%. Forget about that extra 10 grains and keep your speed up. Far worse things will happen if you fall below your velocity threshold and don't get expansion than not having an extra 10 grains in bullet weight.

 

[blueridge]

Thank you both for you input!

I was comparing the 140gr TTSX and the 150gr E-Tip and was trying to choose the right combination of velocity and energy. My goal is >2000 fps and >1500 ft-lbs out to 400 yards. At the further distances, the velocities were very similar and the 150gr had the edge in energy, so that's why I was going to go with the heavier bullet.

Until your comments, . . . which got me thinking about the 140 E-Tip, which I did not test. Here are the numbers, conservatively using the same muzzle velocity I'm getting with the 140 TTSX (2820). I didn't now just the difference in their ballistic coefficients (140gr TTSX: 0.412; 140gr E-Tip: 0.489) would make such a difference in both velocity and energy. Coming out hotter, the 140gr E-Tip has a substantial advantage on both regards, even versus the 150gr E-Tip.


Looks like I've got a store visit tomorrow.

 

[JLS]

You also need to pay attention to your twist rate. You might not have a fast enough twist to stabilize the 150 grainers.

 

[Brian in Montana]

Just got a box of 139gn Hornady Interbonds for the 7mm-08. Going to try those with Big Game. Might be pretty fast as the IB has a little less bearing surface slightly less weight.

I would assume that less bearing surface would likely increase the speed anyway. Maybe I'm wrong about that.

 

[Aussie_hunter_JD]

For what it's worth my recommendation would be 156 grain norma oryx. I use them in my 275 rigby, which is just a late 1800s less marketed version of a 7mm08. Those things are incredible. So far nothing has ran more than 30 yards.

I've shot hornady, barnes, nosler, woodleigh and a few others.. barnes were always my favourite but had the issue of penciling if they didn't hit solid mass. Oryx seem to go operate well no matter whether it's flesh or bone. Haven't recovered any but they're meant to retain 90% weight.