Problems with copper factory ammo...

[BigPat]

This is one for those with technical knowledge rather than guesswork.....but I also thought it could be an interesting discussion.

I have a .308win Sako75 stainless/Synthetic that has been my go to rifle for 20yrs+ and has taken many deer over that time and is still an absolute tack driver with my chosen hand loads, 150gr Speer SPBT running at 2650fps with N140 behind them.

But when last year I needed to use factory loads in non-lead/copper I did have a few issues finding something off the shelf that worked. After spending a small fortune on different options that I just couldn’t get to group within 1moa, I eventually settled on the RWS HIT rounds in 150gr. They group well and seem to dump enough energy to drop my targets while exiting with a good blood trail if needed.

But this got me thinking. I assume copper bullets are harder?, and as such would the fact that my gun has had several 1000s of rounds through it mean the rifling is showing signs of wear and perhaps is less able to get a decent bite on the harder copper bullets? Could this explain the poor grouping of the other copper factory rounds?
Or,
Is the 1/11 twist rate of my old Sako not right for the new copper rounds, perhaps because they are being pushed faster or perhaps because they need a faster twist to stabilise them? What is the optimum twist rate for the .308win using copper bullets in 130gr or 150gr?
Or,
Do copper bullets prefer a longer/shorter barrel? My Sako is 22.5” or thereabouts.
Or,
Is there some other factor I’m missing here?

The final bit for me would be to ask our resident experts. If you were having my rifle rebarreled what length and twist would you go for to maximise the effectiveness of 130gr/150gr copper bullets?....and why?

 

[long_range_rob]

In my experience you’ll have more luck going heavier. I’ve a friend who uses a .308 Sako85 and only uses 165gn GMX or the new Sako Powerblade in 163gn. They group 1/2MOA and work admirably

 

[BigPat]

Thanks for the input.
My issue with heavier loads is that when you consider the minimum velocity that most state for effective expansion then figure in the down range speeds you seem to end up with little more than a 200yrd max range. Hence the lighter bullets pushed hard and fast seem to be a better option for longer range hunting.
But it was more the barrel element of the equation that I wanted to understand so when I do eventually get the gun rebarrelled I don’t go wrong.

Ps. I did try 165gr GMX without success but I never tried the Powerblade.
Pps. The gun has never been picky about ammo and every traditional round I have used has always been sub Moa.

 

[baguio]

This is one for those with technical knowledge rather than guesswork.....but I also thought it could be an interesting discussion.

I have a .308win Sako75 stainless/Synthetic that has been my go to rifle for 20yrs+ and has taken many deer over that time and is still an absolute tack driver with my chosen hand loads, 150gr Speer SPBT running at 2650fps with N140 behind them.

But when last year I needed to use factory loads in non-lead/copper I did have a few issues finding something off the shelf that worked. After spending a small fortune on different options that I just couldn’t get to group within 1moa, I eventually settled on the RWS HIT rounds in 150gr. They group well and seem to dump enough energy to drop my targets while exiting with a good blood trail if needed.

But this got me thinking. I assume copper bullets are harder?, and as such would the fact that my gun has had several 1000s of rounds through it mean the rifling is showing signs of wear and perhaps is less able to get a decent bite on the harder copper bullets? Could this explain the poor grouping of the other copper factory rounds?
Or,
Is the 1/11 twist rate of my old Sako not right for the new copper rounds, perhaps because they are being pushed faster or perhaps because they need a faster twist to stabilise them? What is the optimum twist rate for the .308win using copper bullets in 130gr or 150gr?
Or,
Do copper bullets prefer a longer/shorter barrel? My Sako is 22.5” or thereabouts.
Or,
Is there some other factor I’m missing here?

The final bit for me would be to ask our resident experts. If you were having my rifle rebarreled what length and twist would you go for to maximise the effectiveness of 130gr/150gr copper bullets?....and why?

I have worked up loads in the same rifle as you and didn't find them as forgiving as lead. I was still able to get stuff to group though, they just needed a bit of fine tuning. Personally, I doubt it's your barrel wear. I think you just need to home load or try some more brands of factory if home loading isn't allowed.

 

[Overlay]

I have had good results with the Sako power blade, been using on Fallow does not had a problem and accuracy is very good
I got some of mine from the gunshop in Swaffham

 

[paulbshooting]

I switched to 130 grains barnes TTSX from 150 g lead sometime ago in my 308s. Both home loaded and accurate. Happy with the copper and never going back. Never needed heavier bullets, use on it all from small muntys through to large fallow and red hinds.

 

[yellow belly]

Fox 130gr works a treat in my old T3 .308 1 in 11 twist.

Go lighter, I'd even use 110gr for reds, it wont drop them like the 130's would but will ethically kill them

 

[Selous]

My 308 wears a 20 inch 1:10 twist barrel and I have never had issues stabilising 130g TSX or TTSX. What I have noticed is that the rifle seems to shoot better with a squeaky clean barrel. As an example here is the target I shot yesterday with a 10 round ladder test with incremental loads in 0.3 grain increments that was shot at 100m. I didn’t allow the barrel to get hot but I didn’t take more than 10 minutes either. The barrel had just been thoroughly cleaned using a borescope to verify and the grouping was much better than I was expecting in a barrel with almost 20 years of use! The left group was with the 130g TSX and the right group with the 130g TTSX using the same increments.

 

[finnbear270]

I found the advice given to me was to clean out hard, between monometal bullets and lead core jacketed bullets worked.

 

[Pkiernan]

I had a 308 that would group 1" at 200m with 180 grain rounds but would have 6" vertical strings with 150 grainers.

 

[Uncle f]

Light for calibre drive them faster should be fine. Try and achieve around 2700fps at the muzzle would be ideal

 

[NP435]

Thanks for the input.
My issue with heavier loads is that when you consider the minimum velocity that most state for effective expansion then figure in the down range speeds you seem to end up with little more than a 200yrd max range. Hence the lighter bullets pushed hard and fast seem to be a better option for longer range hunting.
But it was more the barrel element of the equation that I wanted to understand so when I do eventually get the gun rebarrelled I don’t go wrong.

Ps. I did try 165gr GMX without success but I never tried the Powerblade.
Pps. The gun has never been picky about ammo and every traditional round I have used has always been sub Moa.

Barnes advises total jacket fouling removal before shooting all copper projectiles, seems it works in my experiences with 6 barrels. Is copper harder on lands and grooves I would hope no as copper is softer than steel but my usage hasn't been extensive enough to know.

 

[NigelM]

Pat, your 150 BTSP is 1.071" long. I can't find a length for the RWS HIT bullet but a 308 150gr TTSX is 1.300". It will be very similar. The additional length is effecting stability, although the calculator says 11 twist should be enough to stabilise.

The advise when changing to copper is to drop down a weight or two both to compensate for the additional length and achieve stability in marginal twist rate barrels and to achieve the additional velocity the copper bullet needs to expand. As others have said above a drop to 130gr will likely solve your problem.

 

[muddy42]

Barnes advises total jacket fouling removal before shooting all copper projectiles, seems it works in my experiences with 6 barrels. Is copper harder on lands and grooves I would hope no as copper is softer than steel but my usage hasn't been extensive enough to know.

Most lead bullets are coated in copper jackets anyway, so I wouldn't have thought this would be an issue?

 

[Shabz]

I’ve been having a similar problem. I want to shoot .270 110gr ttsx but can’t get them to group. My strategy so far has been to change rifles but I’m now on a brand new Sako 85 and still they won’t group. I’ve finally given in and bought some different copper bullets at 130gr to see what they do.

 

[Buchan]

I’ve been having a similar problem. I want to shoot .270 110gr ttsx but can’t get them to group. My strategy so far has been to change rifles but I’m now on a brand new Sako 85 and still they won’t group. I’ve finally given in and bought some different copper bullets at 130gr to see what they do.

Fox 130 group well in my 85. I found the factory 150 rounds groups OK at 100, but I did see the lack of expansion on one beast. I'd misranged it (thought it was 200, was 280) and it went through the front of the liver with a wound channel as if a stick had been pushed through it. Needed follow up shot.

 

[Bowland blades]

Most lead bullets are coated in copper jackets anyway, so I wouldn't have thought this would be an issue?

With a softer lead core , the jacket in copper is very thin and far more compressible than solid copper monolithic.
Most copper and brass bullets rely on driving bands instead of full contact and tge attempt to squeeze tge harder copper down the rifling

 

[Selous]

I’ve been having a similar problem. I want to shoot .270 110gr ttsx but can’t get them to group. My strategy so far has been to change rifles but I’m now on a brand new Sako 85 and still they won’t group. I’ve finally given in and bought some different copper bullets at 130gr to see what they do.

Have you really cleaned it so there is no fouling? For about £50 you can buy a Teslong bore scope that reveals exactly how inadequate cleaning protocols have been. Unfortunately getting a clean patch through doesn’t mean that the barrel is clean!

 

[Shabz]

Have you really cleaned it so there is no fouling? For about £50 you can buy a Teslong bore scope that reveals exactly how inadequate cleaning protocols have been. Unfortunately getting a clean patch through doesn’t mean that the barrel is clean!

It’s a new rifle. Cleaned before use.

 

[BigPat]

Thanks for all the comments, I will definitely try some of the lighter factory copper offerings if I need to use factory loads in the future.

BTW - the RWS HIT ammo that I found worked ok are 165gr not 150gr that I stated earlier.

So what about my question...

” The final bit for me would be to ask our resident experts. If you were having my rifle rebarreled what length and twist would you go for to maximise the effectiveness of 130gr/150gr copper bullets?....and why?”