Ladder for 7mm Rem Mag

[AKHunterNorthPole]

I am working up a load for my new A-bolt/leupold 4.5-14x 40 w/cds combo. I am using Berger 168g, H4831 and FED 215. The load data I got from Berger didn't have H4831 so I loaded rounds using a low starting load (60g) and worked up to 65 in .5g increments. I loaded some extra rounds with 60g for fouling shots and to get a fair zero before starting load development. I shot a .862 5 round group with the 60g of H4831 at 100yds. I then continued with the ladder test and had some nice groups with powder charges of 62g - 64.5g. So I guess my question is if I shot a .862 5 rnd group at 100yds should I go with that or try to squeeze some more MV out of that 168g Berger? Another question is how do you all measure your groups? I measure from the outside to the outside of the furthest bullets and then subtract the caliber.

 

[Kevin Thomas]

You've already started the process, so why not go ahead and find out which load truly delivers the the finest accuracy? All too many shooters base their reloading preferences on what would be accurately described as a statistically insignificant sample. Takes a rather large number of rounds before you can truly develop a solid opinion on which of several different loads actually delivers the best accuracy, especially if the group sizes are failry similar to begin with. Look at it this way, it's more opportunity to spend some range time getting to know your rifle and ammo all the better. Got some great reloaders in your neighborhood (including my best friend) who should be happy to get you going here.

You got it; outside edge to outside edge, and subtract the bullet diameter. No problem at all.

Kevin Thomas
Lapua USA

 

[kiwi3006]

Do you know what velocity you are getting?
A lot of the reloading data for 7mm mag is very conservative. I use 72gr H1000 with 168 berger 215 federal federal brass and am getting 3060 fps from a 26" barrel.
If you don't get great results from your ladder, try this. Load up until you hit pressure signs, sticky bolt, ejector marks on the case, back off 2 grains, then try the seating depths as suggested by berger (Use the longest seating depth first).

Stu.

 

[AKHunterNorthPole]

I didn't use my chrono because honestly I only wanted to concentrate on getting the best groups first and only worry about one thing at a time. I will be using this rifle for hunting in Alaska so I want to load from the magazine which limits my seating depth. I am seating the farthest out my magazine will allow. I need a good combo of accuracy, power and reliability up here, there are big brown furry critters up here! There was no data for H4831 from Berger and the closest they had to it as far as from the burn rate chart was RL-22 and H4831sc so I started with those numbers. I went up to 65g because they list 65 as max for RL-22. I am going to do it again and probably go up to 67g or so looking for pressure. If you are using 72g H1000 and they (Berger) list 69.5 as max I can probably push a little more.

 

[texan79]

Berger load data seems very conservative to me. I start at their max and have had no trouble.

 

[roninflag]

AK- max in sierra manual for 168 is 65.6 for H-4831. i favor "soft " bullets like the 168 berger . i shot a rocky mtn big horn( big maybe 270 pounds) almost broadside . 296 yards . it did not go through. the sheep went maybe 5 to 8 yards and fell over. if i was shooting at something BIGGER/HEAVIER (like A grizzer) than a caribou or black bear. no question, i would use a different bullet. " harder " like an accubond. i got great accuracy with them on paper. i don't have to worry about that in az.

 

[Miller Outdoors]

I didn't use my chrono because honestly I only wanted to concentrate on getting the best groups first and only worry about one thing at a time.

To learn the most out of a ladder test I'd prefer to shoot through a chronograph with no target to shooting at a target with no chronograph.