7mm-08 not producing decent groups with Accubonds

[JGRaider]

Nowhere in the OPs statement does he give any cbto vibes. All his numbers are coal length acceptable. Also, and I agree cbto is a better measurement, but using coal measurements can work as well. Many people make highly accurate ammo just using coal measurements.

Just my opinion, his gun doesn’t like those bullets he’s trying to use.

Not sure how you can say that since we have no idea of the powder charge he's been trying.

 

[Pickettpuncher]

Not sure how you can say that since we have no idea of the powder charge he's been trying.

Since he’s tried “vargent” and big game powder at “various charges”, and it won’t do better than 2.5”, I’d say it don’t like that bullet.

 

[JGRaider]

I've never had a 7-08 that didn't like a 140 AB with either Varget or Big Game so I find it hard to believe, IMO/IME of course.

 

[Pharmseller]

“Various charges” tells me nothing.

I make cookies with various amounts of sugar but they all taste like shit.

See what I mean?




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[williaada]

Not sure how you can say that since we have no idea of the powder charge he's been trying.

My powder charges have been in the ladder form for the accubonds.
Vargent 41.0, 41.5, 41.8, 42.0- 2” or larger
Big game 47.3, 45.0, 45.5 -2” or larger

Barnes 120gr TTSX- first time running copper
Vargent- 42.0, 42.5 43.0, 43.5* (most accurate 1.5 group of 5.

Going to clean the gun this evening before next range outing.

Also, what is the other measurement, and where do I measure for this?

 

[A382DWDZQ]

“Various charges” tells me nothing.

I make cookies with various amounts of sugar but they all taste like shit.

See what I mean?




P

Your oven obviously doesn’t like the flour.

 

[LaHunter]

My powder charges have been in the ladder form for the accubonds.
Vargent 41.0, 41.5, 41.8, 42.0- 2” or larger
Big game 47.3, 45.0, 45.5 -2” or larger

Barnes 120gr TTSX- first time running copper
Vargent- 42.0, 42.5 43.0, 43.5* (most accurate 1.5 group of 5.

Going to clean the gun this evening before next range outing.

Also, what is the other measurement, and where do I measure for this?

The 'best practice' for measuring for seating depth is CBTO (Cartridge Base To Ogive). I use the Hornady Lock n Load compartor set. You will need a set of digital calipers also. You can probably find some youtube videos on this item. Using the CBTO measurement allows for much more consistent ammo and better precision. Hornaday also has a kit for measuring headspace of your brass that is very similar to the bullet comparator kit.
Also, google Alex Wheeler method for finding the lands. There is a youtube video for that out there on the interwebs.
Last, go to the RCBS website. On the home page over to the right there is a tab named 'Learn'. Click on that and there is some good information.

Good luck.

 

[Vern400]

Load up 5 identical to the others but 0.010 off the lands. IF the group tightens up A LOT then you know what your Winchester wants. I went from 1.5 normal group to 0.78 max group of 4 groups doing that. You'll have to single load. But at least you will prove or disprove root cause.

No good result? Change powder/ bullet combination.

 

[Vern400]

I don't if it helps, but we were at the range last week and my buddy's sig won't shoot factory Nosler 168's in his 308. Switched to his 165 hanloads with Sierra gamechagers and it was sub moa. That barrel just did'nt like the 168 Noslers.

Yes I have seen that too.

 

[Vern400]

Yes he's still got a lot of bullet jump. Some guns can take that and some can't. And of course some just won't shoot at all ..

I have had good luck with 160 grain Nosler AB bullets in 7 rem mag. As far as bullet seating, I have had good luck starting with .015" from slightest contact from lands.
These bullets have always been pretty forgiving / easy to get to shoot accurately for me. Maybe a different powder will help?

 

[Vern400]

Will give it a cleaning, are any of the other bullets copper?

Sometimes I use sweets 7.62 copper remover. Won't take out hard carbon but it strips out copper fast. Oil afterwards,! It's nasty but patches go instant green!

 

[Pharmseller]

Is 47.5 grains Big Game (max load) safe in you rifle? If so, use that load with a magnum primer.

Does the magazine length allow you to seat the bullet close to the lands? You might need to try a depth test, that what I do.

Start just barely touching the lands. Not jammed at all. Load 5.

Seat deeper by 0.04”, load 5.

Do this two more times, each 0.04” deeper.

Set up 4 targets and see which depth the rifle likes. If you find a good but not great load you can go plus/minus 0.02” to fine tune.

This process has never failed me. Stole it from Berger.




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[williaada]

I've never had a 7-08 that didn't like a 140 AB with either Varget or Big Game so I find it hard to believe, IMO/IME of course.

Is 47.5 grains Big Game (max load) safe in you rifle? If so, use that load with a magnum primer.

Does the magazine length allow you to seat the bullet close to the lands? You might need to try a depth test, that what I do.

Start just barely touching the lands. Not jammed at all. Load 5.

Seat deeper by 0.04”, load 5.

Do this two more times, each 0.04” deeper.

Set up 4 targets and see which depth the rifle likes. If you find a good but not great load you can go plus/minus 0.02” to fine tune.

This process has never failed me. Stole it from Berger.




P

Thanks, yes it was max load no issues, why would you use a magnum primer vs large rifle primer.

I will try your suggestion on the bullet seating as well. Will report when I have done it. Right now getting ready for my elk hunt.

 

[JGRaider]

I'm not Pharm, but I echo his practice of using magnum rifle primers with ball powders even in non magnum cartridges. Sometimes you won't see a difference, but way more often than not it makes a big difference for the better.

Pharm has pretty much perfected accurate hunting loads in the 7mm08 using 120, 140, and 150 gr bullets.

 

[Pharmseller]

Thanks, yes it was max load no issues, why would you use a magnum primer vs large rifle primer.

I will try your suggestion on the bullet seating as well. Will report when I have done it. Right now getting ready for my elk hunt.

I take no credit for the magnum primer. A prominent gun writer on another board promotes the use of magnum primers with ball powders. I’m smart enough to take good advice.

I load for my family and we shoot a lot of 7mm-08. All the rifles are Tikkas, however, which makes my job much easier.

Speaking of elk, my dad shot his last and biggest bull with 47.5 gr of BG with a 140 gr AccuBond. One shot, 7mm-08.

Two years later my nephew killed his first bull, a 5x6, with a 150 ELDX and 46.2 gr BG, also 7mm-08.




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[Vern400]

Is 47.5 grains Big Game (max load) safe in you rifle? If so, use that load with a magnum primer.

Does the magazine length allow you to seat the bullet close to the lands? You might need to try a depth test, that what I do.

Start just barely touching the lands. Not jammed at all. Load 5.

Seat deeper by 0.04”, load 5.

Do this two more times, each 0.04” deeper.

Set up 4 targets and see which depth the rifle likes. If you find a good but not great load you can go plus/minus 0.02” to fine tune.

This process has never failed me. Stole it from Berger.




P

You nailed it. He's nowhere close to the rifling even if that would be a single load requirement just for root cause analysis

 

[Firehawk]

We have 3 7-08 rifles in our home, and two friends with 7-08 chambered rifles. A Browning A Bolt, Tikka T3, Winchester M70, Kimber Montana and a Remington Model 7.

All of them like Varget powder. The ones in my household all shoot sub MOA with 140 Btips, 140 Abonds and 139 Hornady SP bullets. With that said, with the Model 70 that was our first, did not shoot 140 partitions well. And Hornady SST bullets wouldn't shoot a 3" group with the H414 I tried or IMR 4350, or IMR 4064. Never tried them again after trying Varget powder.

We also found RL17 to be a great powder in this cartridge.

 

[Rob5589]

In my Tikkas, R15 and CFE223 have given the best results with the 120TTSX. I use a mag primer with the CFE, BR2 with the R15.

That said, has your rifle ever produced what you would consider a good/reasonable sized group? Some barrels are just duds.

 

[DiabeticKripple]

maybe the guy cant shoot for shit....

 

[Pharmseller]

We have 3 7-08 rifles in our home, and two friends with 7-08 chambered rifles. A Browning A Bolt, Tikka T3, Winchester M70, Kimber Montana and a Remington Model 7.

All of them like Varget powder. The ones in my household all shoot sub MOA with 140 Btips, 140 Abonds and 139 Hornady SP bullets. With that said, with the Model 70 that was our first, did not shoot 140 partitions well. And Hornady SST bullets wouldn't shoot a 3" group with the H414 I tried or IMR 4350, or IMR 4064. Never tried them again after trying Varget powder.

We also found RL17 to be a great powder in this cartridge.

Varget is an excellent choice. I got slightly better groups but much better velocity with BG.




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