7mm08 - Load development

[HuntClub]

OK - asking for input: What is the next test load recommendation. I have an idea about what I would like to try but would love to get input from fellow shooters.

Picture below - top three all same powder load BUT different seating depth. Bottom three increased powder load by 0.4 grains and used same seating depth as target above it.

So, specific target load per row and each target (left to right) moves closer to the lands. Left side is working at 0.100 from lands. the target to far right on each row is maxing out COAL.

 

[Dou8leD]

I like the group on the bottom middle, I would get a lil closer to lands depending on your magazine.

 

[dhagerty40]

all I can tell you is what my 7-08's like. Both like around .010-.020" off the rifling. You are a Whole lot more than that. Both are Single shots, so I do not worry about feeding through a Magazine. But Most of the Manuals I have list a Max length for magazine of 2.800"

 

[AckleymanII]

my 7/08's like the bullets to be touching or barely off. I deer hunt with the 130g Speer spt bt or 130g Hot core, 42g of IMR 4895, rem 9 1/2, rem brass, with tiny groups, deer flop. Have many converts after they borrowed my rifle and ammo.

 

[Murray Brook]

First 7/08 I had liked the 168 Sierra .010" off the lands with WW760. Current 7/08 I have likes the 171 Barnes match burner at .120 off the lands and again with WW760.

 

[std7mag]

Powder charge first. Then go for group size with changes in seating depth.

The all copper Barnes your using like a jump.
Barnes suggests 0.050" off the lands to start.

 

[dhagerty40]

They are right. Barnes do like more jump than other bullets.

for the hell of it, I ran your load through quickload. It shows that you are getting into the warning area for pressures. So please watch for pressure signs.

 

[HuntClub]

They are right. Barnes do like more jump than other bullets.

for the hell of it, I ran your load through quickload. It shows that you are getting into the warning area for pressures. So please watch for pressure signs.

Shooting a Bergara with 20" heavy barrel - no pressure signs but the barrel sure did heat up quickly. Not at max load using Barnes data but am also looking to go back and test the lower end loads now as well

 

[LHSmith]

Bottom middle- the holes look smaller for caliber and the holes are centered in the black halo. Other groups the holes are oblong.

 

[ATFIV]

7mm-08 loves IMR 4064

 

[Topwater]

I would experiment more with the bottom middle load. I’d try .2 gr. increments in powder charges. Then I would vary the seating depths. Good luck with your efforts.

 

[Infrequent Shooter]

the bullet in Hornady Superperformance works well in HB Savage. It is 139gr polymer tip, if that is any help. Very accurate.

 

[std7mag]

Personally, i'd say you need to do your ladder test with powder. Decent amount of vertical in all your groups.

 

[dfry]

I would kind of agree with working the powder charges with the bullet .050 off. I can say I shoot a lot of TSX and TTSX Barnes in my hunting rifles, and almost all of the bullets like speed and all of them are .050-.060 off the lands. I have a Ruger 22” M77 stainless in 350 RM that was just an ok shooter until I worked a load up with the 200 TSX and ended up .050 off with IMR 3031 at a max load at 2900 FPS that will shoot 3 under 1/2”. The 3031 load was actually out of the Lee load manual of all things. That rifle barks and holding it steady enough to shoot that tight of a group (and it does it consistently) was a miracle in itself. Just an example with Barnes.

I would suggest Varget, H4895, or IMR4064 with the 120 TTSX. But that is just a guess based off what my Tikka 7-08 likes with that bullet.
My 06, 7RM, and 270 all ended up at .050-.060 off with Barnes. Not saying that your rifle may not like more or less jump, just that I ended up pretty much right where Barnes says. All those rifles like speed with Barnes. I tried lower velocity loads and all of them didn’t group great until the velocity got up there.

 

[ChrisNZ]

Very small sample size, too small to really say much. One observation looking at the two right groups- the 11 0'clock stringing is suggestive of variable shoulder pressure, assuming you're a R-shouldered shooter.

As for powders, Varget/RE15/ VV N140/CFE 223 are all good options with that chamber/bullet combo. My 16" bbl does over 2900 with CFE and it sure kills.

 

[std7mag]

I'm guessing RL15 is what the OP has.
And that's fine. They are getting decent velocities with it & the 120gr bullet.

I'd start off with 0.050" off the lands & do a ladder test.
Then do seating depth test. Following reccomendations from Barnes load manual.

If your still having issues with group size, try putting a crimp on. I've found this to help.
Theory is allows pressure to build that milisecond longer, and helps the bullet to build up speed before it hits the lands.