Effect of moderators on POI

Buchan

Well-Known Member
Hi all,

I'm relatively new to stalking so bear with me if the following is b obvious. I have a Sauer 202 Euro in .243. I previously had it nicely zeroed at 100 paces (yet to buy the rangefinder) with a ASE Ultra moderator giving an inch group. The results below were from today's zeroing as the ASE wasn't for sale after all and I bought a Wildcat 8.

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Top Left
Sauer 202 Euro .243, Wildcat Moderator, 100gr Federal.
Red: initial group
Green: at maximum elevation for sight (S&B 3-12 x50)
Top Right
Pink: as above.
Blue: 80gr Nosler (home load)
Red: No Moderator, 100gr Federal
Bottom Left
Sako 85 .308 T8 Moderator
Red: 150gr home loads
Blue: without moderator (two shots touching – gone a bit pink!)
Bottom Right
Sauer with T8 moderator, 100gr Federal.

Change in POI compared to no moderator
Wildcat on Sauer = 6.5 inches lower
T8 on Sauer = 3 inches lower
No change in POI with Sako 308 and T8

Wildcat weighs 860g, T8 750g. (The ASE wieghed, from memory slightly more than the T8).
I can understand the moderator making a difference, but this seems excessive. Given that there was no change with my Sako, is this a problem other Sauer users have encountered?


Cheers,
 

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I can't really answer your question but can tell you that my Blaser shoots about 6 inches low and an inch to the right with the mod off compared to having the mod on.

I suspect if you were to get another Sako in 308 it would shoot somewhere completely different with the mod on/off and it is just luck that you've got one that doesn't show any change.
 
Strange, my sako 25-06 shoots 4 inch high with mod off, and consequently 4 inch low with it on.Would have thought it was all to do with barrel harmonics, but doesn't logic suggest that you should shoot lower with a mod on??
 
Sounds to me like the barrel is touching the stock on the Sauer with the moderator on and free floated without.

Is it factory threaded?/?? If not check the crown and get a second opinion.
 
There really seems to be no hard and fast rule on this whether the rifle will shot high, low, left or right with the mod off once it's zeroed for the Moderator. Occasionaly we find a rifle that makes no difference. All we can do is check and find out how OUR rifle behaves in this respect.
 
Just had a look at your targets and whilst I know you are comparing on and off moderator effects, I would also say that your grouping at 100 paces should be a lot tighter regardless of using a mod or not. When did you last clean your barrel, how old/worn is rifle- both could significantly affect grouping. Then there is the human factor......
 
My tikka T3 will shoot sub inch with or without mod but when zeroed without mod when the mod is fitted it hits the bottom right hand corner of a centred A4 target.

Dave
 
it appears i am one of the lucky one's i zeroed my sako 75 hunter in .308win at 100 yards without moderator had a nice 1/2" group
re-zeroed again with moderator on after purchasing my wildcat predator 8 from R&B Sporting in ross-on-wye no change to point of impact at all
nothing!! no change what so ever apart from less recoil, noise and weight of rifle increased
 
Just had a look at your targets and whilst I know you are comparing on and off moderator effects, I would also say that your grouping at 100 paces should be a lot tighter regardless of using a mod or not. When did you last clean your barrel, how old/worn is rifle- both could significantly affect grouping. Then there is the human factor......

Fair comment. as I said, relatively new to this, but I'd expect better groups myself. The barrel was clean (done every time used), and in good order (been scoped). I had a good look this evening, taking the scope off and re fitting it, removing the stock. The fore end does touch the stock and it is harder to pull paper through with the moderator on. I suspect this might be a problem.
 
When I got my first .308 I bought it with a mod on it. Bore sighted it as the book says and a mate took me to the range at Bisley to give it a go and learn some lessons. Couldn't even get a bullet on the target! Serious confidence knock. Got a couple of experienced people to look at it while I was there and they had the same problem. Took the mod off and it shot perfectly well. Turned out there was a burr inside the mod that was knocking the round way off centre. Changed the mod, problem solved, lesson learnt.
 
The groups are poor with mod on or off, but worse with it on. Get it free floating with both and then have a go. Cannot hurt and wont cost you a penny.

If you have a mate with a different mod same thread it might be worth a play afterwords.

Not sure a "burr" inside a mod would last long if a bullet was clipping it @ 3000 ft/sec

Keep it simple.
 
my Brno 98 sporter 243 with P8 doesn't affect group size, but bill always shoot 6" low with it on.

I always have meant to chrony with the mod on and off. Unless it's barrel deflection, I wouldn't be all that suprised if there was a velocity drop...
 
I am currently testing a .243. It was not grouping like I know it should so a little playing was called for. Turns out the newly acquired scope is suspect. During the short test, limited amount of ammunition available, I broke a golden rule and changed three things at once however it proved the scope was not holding reticle position :rolleyes: so it will need a repair. One thing did come to light once again the grouping improved with more jump for the bullet. Seated out near the leade grouping was pretty poor.

Trying it initially with the P8 grouping was poor so I finally changed scopes and shot it bare barrel. Once I get some more bullets I will re-test with the moderator and see how it does and if it alters the POI.
 
I use Norma 110gr Vmax with a T8, if I take the moderator off and up the bullet weight to Federal 150gr the zero is still perfect.

Found this out by complete chance.
 
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