7-08 / Big Game

[Brian in Montana]

This was the product of a 21 round ladder test: 7mm-08; 140 Nosler AB; Ramshot Big Game (43.5gn - 47.5gn); Fed 210M primers. I went pretty much exactly by the data published by Nosler. I'm not really altogether sure what to do with this. Most ladder tests I've done look like a shotgun blast. This looks like I could pretty much just pick the velocity I want and go with that.

 

[brockel]

Distance?

 

[Dougfirtree]

You're clearly going to need a less accurate rifle if you want to continue with these ladder tests...

 

[Millsworks]

That reminds me of the ladder testing I did years ago with my .260 Remington.
The only groups I could differentiate were with 160gr. loads. It didn't like those.
You probably have a life long shooter there.

 

[MThuntr]

take it to 200 & repeat. you obvious have too accurate of a rifle.

 

[N2TRKYS]

Ladder test are a waste of time.

 

[brockel]

Go to 300. Will show you more

 

[Bigjav]

Now I'm by no means an expert, but it looks like you've got a shooter there

 

[std7mag]

Brian,
Impressive 21 shot group!
I usually only do 10 shot ladder tests. 1 round per 0.3gr increment.
Watching where each shot goes with spotter scope. Numbering each after 3 shots.
Hence keeping track of powder charge.
When i get targets that look like yours i increase the distance 100 yards and repeat.

I never understood using 3 rounds per charge increment as your just looking for vertical spread between charges, group size is done with seating depth, and tuning your action.

 

[Don Fischer]

Go to 300. Will show you more

Oh no. Better to go to 500!

 

[Brian in Montana]

I'm actually using the magnetospeed doing a ladder test based on muzzle velocity. I've done it a handfull of times and although I'm still pretty new to the theory of it, there does seem to be something to it. I've done several ladder tests between my .308 and my wife's .270 and have come away with some pretty good loads to refine - one being 165gn Federal TBT's in front of 43.3gns of H4895. I've followed up a couple times on that one and it's consistently about .75 at 100yds.

My distance on this one is only 100yds and the pic of this target uploaded sideways (you can see a slight trend of vertical stringing, but only very slight). I used 21 rounds on this ladder test because I was using Big Game, a spherical powder, and its different from the stick powders I've worked with in the past (Varget, H4350, H4895, H4831SC). I went exactly with the load data published on Nosler's website for the 140gn AB's in 7mm-08 which ranges from 43.5gn (min) to 47.5gn (max). All the velocities published are something I'd be happy with in this rifle, so I just decided I'd run the entire range to see what might happen; started at 43.5 and increased each successive charge by .2gns for a total of 21 rounds. I record all the MV's and in the analysis afterward, look for places where the velocities don't change much, like 5-10 fps between 3 shots.

When I've done this in other rifles, I generally used a dozen rounds because I'm more familiar with the velocities the powders would produce and have a better idea of what I'm looking for. Even with those dozen or so rounds, you can see some trends - stringing and such - at 100yds, but they certainly don't all go into the same hole like this one did. I haven't really poured over the velocity data yet, but I'm feeling pretty confident I'll be able to find a really good load out of this.

This is all pretty interesting stuff. I should have started handloading years ago.

 

[brockel]

What velocity was your flat spot?

 

[belly-deep]

Ladder test are a waste of time.

90% of the time, this ^^^

Go to 300. Will show you more

But for the 10%, this ^^^

 

[std7mag]

Wholey disagree with this^^^. Lol

www.sierrabulletsblog.com>2014/07/03

And i bet your POI is different when you take the MagnetoSpeed OFF of your barrel.

Why we need to keep re-inventing the wheel is beyond me.
KISS- Keep It Simple S-----!

 

[VikingsGuy]

Wholey disagree with this^^^. Lol

www.sierrabulletsblog.com>2014/07/03

And i bet your POI is different when you take the MagnetoSpeed OFF of your barrel.

Why we need to keep re-inventing the wheel is beyond me.
KISS- Keep It Simple S-----!

Magnetospeed adds a variable no doubt (and this is why I gave mine to my SIL), but the LabRadar really makes this approach sing. When first starting to use velocities I also did in tandem with ladder and saw really good correlation. So, why add the LabRadar? Because I get the same data even if I can only get on the 100yd range, wind doesn’t change the data, barrel temp is not a factor, and it takes my shooting error out of it. So, OCW will work, ladder tests will work and so will velocity approach - but I find the velocity approach quicker and more flexible to my various shooting environments..

 

[Brian in Montana]

What velocity was your flat spot?

Several flat spots came and went throughout. Seem to have a good ones at about 2730, 2760, and then a lot of variance until about 2850 fps. I was starting to get some pressure signs at that point, slightly cratered primers, so I'm reluctant to work on that much. I've hear cci primers are made from harder material than federal (using fed 210M), so I might try that if I decide to push it a little.

 

[Brian in Montana]

I did a lot of reading and YouTube watching of late about using a magnetospeed in load development - basically ladder testimy based on MV rather than POI. Its kind of my project right now to experiment around with the concept and see how it will ultimately fit into my process. I'll admit I was leery at first, and doubtful of my own handloading skills, but after running through it a few times, there does seem to be some sound theory behind it. I've found a couple loads that my .308 seems to like and one for my wife's .270. Still working on how exactly I'll use it in the long run.

I'll keep posting results.

 

[OhHeyThereBen]

That's some good shooting Brian! Glad to see it's working out for you.

 

[Europe]

Wholey

Why we need to keep re-inventing the wheel is beyond me.
KISS- Keep It Simple S-----!

Gentlemen, please accept this post in the light hearted manner it is intended.

When I saw the above from std7mag I smiled and wondered how we ever were able to harvest any animals in the 1940's ---old rifle, store bought ammo, dad said hit those cans on the fence post out there and when I got all three of them, he said "your ready" lol

On a serious note, this thread is interesting to me and I have asked others---younger others--for more info as it is always good to learn

 

[std7mag]

Good points, Europe!
And i appologize if i offended. Was not meant offensively.
Ladder is what i learned, works for me.
Guess i have a hard time deviating from something that works for me.

Carry on group!