Loss of accuracy with light sound mod with non toxic Ammo - fine with lead Ammo

[Jon P]

Recently purchased a DPT sound mod for my 30-06 and noticed the RWS non toxic 165 g (Green) are not grouping well at all, was previously using a wildcat sound mod which is lot heavier and had reasonable groupings at 100 yds- the RWS have never been as good as the lead federal powershok but passable. I have fired some powershok back though the rifle with the DPT and got good groups. Would a lighter sound mod make that much difference or am I missing something else-? rifle is Sako 85. I am going to give the barrel another good clean and make sure there is no lead residue left in barrel .
Cheers
Jon

 

[springbok787]

Barrel needs to be super clean for copper ammo or Tin in the case of the RWS. Or it could just be your rifle doesn’t like the RWS which happens.

 

[Jon P]

Barrel needs to be super clean for copper ammo or Tin in the case of the RWS. Or it could just be your rifle doesn’t like the RWS which happens.

Best I could ever get out of it at 100 yds with RWS was a 1 inch group with wildcat mod - I lucky to get 3 inch group at mo, may just be coincidental with sound mod and barrel needs a deep clean.

 

[RCS Deer Management]

Having a moderator on the end of the barrel affects the tune of your barrel. It is entirely likely that a certain type of ammunition will shoot better with some weights of moderator than others. A moderator is essentially a non adjustable barrel tuner

 

[Jon P]

Having a moderator on the end of the barrel affects the tune of your barrel. It is entirely likely that a certain type of ammunition will shoot better with some weights of moderator than others. A moderator is essentially a non adjustable barrel tuner

Every day is a school day , I did not even think about that, I still have the wildcat mod, will do some tests tests with the old mod

 

[deerstalker.308]

Google barrel harmonics. There is some logic to the variance in performance but I can’t say I’ve ever experienced that, or the need to be a super clean barrel for copper/tin rounds? That’s a new one on me.

 

[Steff]

Barrel needs to be super clean for copper ammo or Tin in the case of the RWS. Or it could just be your rifle doesn’t like the RWS which happens.

No and yes.

No regarding barrel needs to be super clean for copper. This is complete nonsense. It should always be clean. Especially if you change the bullet, be it copper or not.

Yes in terms of that the barrel may not like the RWS. This just happens.

 

[splash]

I bought a light mod for my .260, it shot like sh** !
Put a heavy one on and it transformed the rifle.
Remington model 7 Ss

 

[Bowland blades]

first thing is how does it shoot without any moderator at all ? remove the variable and narrow down possible

 

[Jon P]

I bought a light mod for my .260, it shot like sh** !
Put a heavy one on and it transformed the rifle.
Remington for

This sako still shooting federal powershok ok , will have play around like others have said, I still have wildcat mod too, just gets v expensive checking out all the variables.

 

[User00040]

This sako still shooting federal powershok ok , will have play around like others have said, I still have wildcat mod too, just gets v expensive checking out all the variables.

Could try using one of these: Limbsaver SharpShooter X-Ring Barrel Deresonator, Standard Barrel Size, Rubber

 

[Malxwal]

Your barrel has inherent harmonics, and these are changed when you change the moderator. If you were hand loading, you'd have to go through at least rudimentary load development again if changing moderator; same applies with factory ammo, you may have to go through a box of various types to find out what it likes after changing moderator.
The differences with a rifle that was pretty tolerant of different lead ammo/loads can be exaggerated with non toxic.

 

[Brave Echo Niner]

I wouldn’t be quick to characterise it as non-lead ammunition the rifle doesn’t like, more it’s one type of ammunition it seems to have gone off since the change.

Having played with a tuner brake on my match rifle it’s very evident the effect changing the weight and therefore the harmonic pattern of a barrel can have. Even with a very tiny change I saw changes from this:
Down to these:

(This was with a pre worked up match load developed with a mod, tuning it so the brake matched the mods accuracy without changing seating depth)

So looking at it as a percentage change I’ve seen it go 420ish%. Not dissimilar to what you’re seeing going from 1 to 3 MOA.


Prior to ruling it’s definitely harmonic change though I would give the barrel a thorough clean and ensure everything is tight and properly fitted with no sticks/crud pressing between the barrel and the stock etc. then retry and see if you get similar results. I had a .308 go from very tight groups to over 3” overnight, when I checked my front action screw had come loose and was affecting accuracy.

Ben

 

[Bowland blades]

my own finding is tin and zinc cored bullets just wont shoot nearly as good as solid copper or std copper jacket lead .

 

[Edinburgh Rifles]

Barrel needs to be super clean for copper ammo or Tin in the case of the RWS. Or it could just be your rifle doesn’t like the RWS which happens.

if this the case get rid of the rifle
NO RIFLE needs to be super clean to use non lead
the standard cup and core lead is using the same material in the jacket that is in contact with the barrel

 

[Bowland blades]

if this the case get rid of the rifle
NO RIFLE needs to be super clean to use non lead
the standard cup and core lead is using the same material in the jacket that is in contact with the barrel

i confirm after testing both ways around , indeed either way round this weekend i shot two groups in the 2's slightly over the 100 yards. One group lead seirra pro hunter after using a lot of copper one copper group after the lead pro hunter .

 

[Jon P]

Recently purchased a DPT sound mod for my 30-06 and noticed the RWS non toxic 165 g (Green) are not grouping well at all, was previously using a wildcat sound mod which is lot heavier and had reasonable groupings at 100 yds- the RWS have never been as good as the lead federal powershok but passable. I have fired some powershok back though the rifle with the DPT and got good groups. Would a lighter sound mod make that much difference or am I missing something else-? rifle is Sako 85. I am going to give the barrel another good clean and make sure there is no lead residue left in barrel .
Cheers
Jon

Update- gave the barrel a good clean, bought some Fox 165g Non Toxic Ammo,,grouping very well and has as same zero as the lead Federal Powershok. Tried some RWS again, Slightly better group but nothing to get excited about- my rifle is obviously not a fan of the RWS greens.