zero question

Jonty

hi lads,

I have a few questions for ye.

My current setup is a sako 75 varmint in 308, with a schmidt and bender PH 3-12x50, with optilock bases and rings. Rifle is completely stock. My current bullet is 150gr Hornady soft point.

My question is as follows. From my "zero" at 100yds, it takes me about 14 clicks to get to my 200 yard "zero". So just looking at the box of ammo, the trajectory shows a 200yd zero will be about 2" high at 100yds.

The schmidt's adjustments are 10mm per click at 100m, so approximately 5 clicks should make the scope 2" high at 100yds. Thats a long way from 14 clicks. The scope is tracking 100%.

I haven't chrono'd the rifle, but has anybody else experienced something similar?

zeissman

one 10mm click at 100m works out about 0.36in at 100 yards which is 0.72in at 200yards, so when the rifle is zerod at 100 yards and it takes 14 clicks to zero at 200 yards the bullet drop is 10.08 in.
That is a lot of drop for a 308.
You really need to chronograph your ammo to see what speed its really doing.

Jonty

thanks zeissman,

i was using remington accutip before, and it was the same craic

zeissman

For a 150 grain bullet to drop that much at 200 it would only be doing 1900 to 2000 fps at the muzzle.
You will have to get your hands on a chronograph to see.
Do you know anyone else with a 308 that could try the same ammo in their rifle to compare it with.

Tackleberrywho

Jonty wrote: »

hi lads,

I have a few questions for ye.

My current setup is a sako 75 varmint in 308, with a schmidt and bender PH 3-12x50, with optilock bases and rings. Rifle is completely stock. My current bullet is 150gr Hornady soft point.

My question is as follows. From my "zero" at 100yds, it takes me about 14 clicks to get to my 200 yard "zero". So just looking at the box of ammo, the trajectory shows a 200yd zero will be about 2" high at 100yds.

The schmidt's adjustments are 10mm per click at 100m, so approximately 5 clicks should make the scope 2" high at 100yds. Thats a long way from 14 clicks. The scope is tracking 100%.

I haven't chrono'd the rifle, but has anybody else experienced something similar?

I zero High @ 100 so really a 200 yard zero.
I've 1/4" clicks and 2 MOA adjustments on scope.

I used to use a 100yard zero, but in the past 5 years or so I use a 200 yard zero and have a much higher long range success rate.

I want to chrono Hornady Superperfomance SST's myself. They are flatter shooting than the soft nose and slightly more accurate

Vegeta

Have you had your barrel shortened drastically?

ejg

Get a sheet of paper, fire a 3 shot group at a mark bottom of the
page and click 20 clicks up, fire another 3 shots, then measure the
distance between groups. Just to make sure you have cm clicks....

I sent a scope to Schmidt once for a turret change and it came back with
around 7.5mm clicks???
edi

garv123

have you shot anything at 100 yards with the 0 at 200? sounds like you'd be alot higher than 2" if it took you 14 clicks, 14 clicks is accounting for 14 cm bullet drop at 200 isnt it ?

clivej

Well your more than welcome to come over to me and try it out. I have a sako varmint 75 in 308. I only zeroed last weekend with a new picatinny mount and ring setup. Zero was @100m and I left it 1 1/2" high @ 100m and it was only 6 clicks to get that extra height. I can chrono your rounds as well

zeissman

ejg wrote: »

Get a sheet of paper, fire a 3 shot group at a mark bottom of the
page and click 20 clicks up, fire another 3 shots, then measure the
distance between groups. Just to make sure you have cm clicks....

I sent a scope to Schmidt once for a turret change and it came back with
around 7.5mm clicks???
edi

Do as ejg says.
your scope could be 5mm clicks.
My zeiss has 5mm clicks and it takes me around 9 or 10 clicks to go from 100 to 200. thats with a 308 26in barrel and 155 lapua ammo.

Jonty

Vegeta wrote: »

Have you had your barrel shortened drastically?

Its a stock barrel, full length

Jonty

ejg wrote: »

Get a sheet of paper, fire a 3 shot group at a mark bottom of the
page and click 20 clicks up, fire another 3 shots, then measure the
distance between groups. Just to make sure you have cm clicks....

I sent a scope to Schmidt once for a turret change and it came back with
around 7.5mm clicks???
edi

I'll try this next weekend

Jonty

I don't think I have an alignment problem as such, as the windage is spot on from 100 to 200.

The problem is when i zero for 100 and shoot at 200, with no adjustment, I'm about 10" low, not 4" low like it should be.

ejg

How is accuracy? Any black around the shoulder area of the just
fired brass? Maybe you have an oversized barrel and pressure isn't building up.
If you have a tight fitting patch on the cleaning rod, is the resistance
along the bore consistent?

Go to Clive and check speed. You might have a dicky barrel. How old is
the rifle?
edi

Jonty

ejg wrote: »

How is accuracy? Any black around the shoulder area of the just
fired brass? Maybe you have an oversized barrel and pressure isn't building up.
If you have a tight fitting patch on the cleaning rod, is the resistance
along the bore consistent?

Go to Clive and check speed. You might have a dicky barrel. How old is
the rifle?
edi

Accuracy is fine sub 1 moa at 100yds. Rifle is 4 years old.

There is no black around the shoulder area on fresh fired brass i think. There is no burn marks on bolt either

Vegeta

Really does sound like 5mm clicks or similar so. Lets us know how you get on testing it. 14 clicks at 5mm a click is 70mm. Which is about 2.75 inches, more of a ballpark figure at least.

Definitely Chrono the rounds if you can too

clivej

Jonty wrote: »

I don't think I have an alignment problem as such, as the windage is spot on from 100 to 200.

The problem is when i zero for 100 and shoot at 200, with no adjustment, I'm about 10" low, not 4" low like it should be.

Now that's is sounding very like a reduced MV from your ammo. As you say it should only be around the 1 1/2" - 2" drop if your zeroed @100 and then shoot @200.

So my next question is have you tried using different ammo 'cos you could just have a bad batch.

And do you know how far from the vertical retical zero your scope is now to get out to 100y, it should only be a few clicks up off of the centre turret mark. Mine was about 2"-3" low to start with so that would equate to 8-12 clicks of up, 2-3 MOA @100y, needed to get to the 100y zero.
If you had to dial in a lot more of up to get out to 100y then again that would show a low MV.

Jonty

clivej wrote: »

Now that's is sounding very like a reduced MV from your ammo. As you say it should only be around the 1 1/2" - 2" drop if your zeroed @100 and then shoot @200.

So my next question is have you tried using different ammo 'cos you could just have a bad batch.

And do you know how far from the vertical retical zero your scope is now to get out to 100y, it should only be a few clicks up off of the centre turret mark. Mine was about 2"-3" low to start with so that would equate to 8-12 clicks of up, 2-3 MOA @100y, needed to get to the 100y zero.
If you had to dial in a lot more of up to get out to 100y then again that would show a low MV.

Its the same with accutips. I honestly don't know about the retical zero. Do you think maybe something isn't straight on the rifle?

clivej

Jonty wrote: »

Its the same with accutips. I honestly don't know about the retical zero. Do you think maybe something isn't straight on the rifle?

But I can't see how that would not give you the same amount drop at 200y from 100y.

I'm starting to run out of idea's.

Vegeta

Hang on actually we need to clear something up here.

Jonty if you rifle is zeroed at 100 yards and you shoot at a piece of paper 200 yards away how far is there between where you aim and the where the bullet hits?

Is it around 2-3 inches low?

If so that sounds around right for 308 rounds so I guess then it is not a round issue and definitely a scope issue. As above I strongly believe you have a scope with 5mm adjustments as it all works out and makes sense.

You should be seeing around 2.5 to 3" of bullet drop. 14 clicks at 5mm a click is 70 mm or 2.75 inches. (this would be at 100 yards and not 200, my bad)

Does the model scope you have come in 10 and 5mm options?

EDIT: Actually just reailsed that what I said makes no sense either as it is 10mm at 100 yards. Yeah if the round is dropping the correct amount ~2.5 - 3 inches between 100 and 200 yards then you can ignore the ammo and barrel as that's about right. The only thing that will solve this I'd say is box testing the scope.

Jonty

Vegeta wrote: »

Hang on actually we need to clear something up here.

Jonty if you rifle is zeroed at 100 yards and you shoot at a piece of paper 200 yards away how far is there between where you aim and the where the bullet hits?

Is it around 2-3 inches low?

If so that sounds around right for 308 rounds so I guess then it is not a round issue and definitely a scope issue. As above I strongly believe you have a scope with 5mm adjustments as it all works out and makes sense.

You should be seeing around 2.5 to 3" of bullet drop. 14 clicks at 5mm a click is 70 mm or 2.75 inches.

Does the model scope you have come in 10 and 5mm options?

Lads, I'm going to try and get a few shots off on saturday morning and I'll get back to ye. Too many questions for a monday morning!:D

When I zero at 100, I'm striking about 10 - 11" low at 200.

Scope is a Precision Hunter S&B, which "SHOULD" have 10mm clicks.

The 4-16 Precision Hunter has 5mm clicks, my 3-12 should not.

I'm just gonna go back to the drawing board, and start at 100 yds and do what Edi suggested about checking the tracking.

Vegeta

Jonty wrote: »

When I zero at 100, I'm striking about 10 - 11" low at 200.

Ok I have never owned a 308 but that sounds off for a 150 grain round just going by an on-line calculator.

Ahhhh ok so I assumed you were getting correct bullet drop and the scope was wrong BUT it seems you are getting a lot of bullet drop and the scope is working.

Chrono that rifle.

clivej

So here I have loaded the details of the Hornaday 30 cal SST 150 gr in a Ballistics Calculator, www.BigGameInfo.com with these results. If zeroed @100y then the drop out to 200y is 3.7" and it says you need to come up 7 clicks.




Hornaday SST .30cal
http://www.hornady.com/store/30-Cal-.308-150-gr-SST/

Tackleberrywho

Zero 1.9" High @ 100, and you should be hitting Bull's @200
I can take the head of a rabbit with no hold over @ 200 prone with my .308. Even when I was using the same ammo as you.
I strongly reccomend a 200 yard Zero on all deer calibres (1.e 1" or more higher @100yards)


308 Win 150 gr InterLock® BTSP
Ballistics

Test Barrel (24") Velocity (fps) / Energy (ft-lbs)
MUZZLE 100 200 300 400 500
2820/2648 2560/2183 2315/1785 2084/1446 1866/1159 1664/922

Trajectory (inches)
MUZZLE 100 200 300 400 500
-1.50 1.90 0.00 -8.40 -24.90 -51.40

garv123

Jonty wrote: »

Lads, I'm going to try and get a few shots off on saturday morning and I'll get back to ye. Too many questions for a monday morning!:D

When I zero at 100, I'm striking about 10 - 11" low at 200.

Scope is a Precision Hunter S&B, which "SHOULD" have 10mm clicks.

The 4-16 Precision Hunter has 5mm clicks, my 3-12 should not.

I'm just gonna go back to the drawing board, and start at 100 yds and do what Edi suggested about checking the tracking.

a .22 wmr wouldnt even drop that much:pac:

Jonty

as regards muzzle velocity, i haven't noticed recoil getting softer

Jonty

update - did Edi's suggestion of firing 2 groups at 100 yds, one at "zero" and the other 20 clicks higher.

Working out the difference, the scope is 5mm per click. Someone of my expererience should have copped this sooner.

Thanks for all the help lads. Ye all made me think, which is a good thing.

Tackleberrywho

Jonty wrote: »

update - did Edi's suggestion of firing 2 groups at 100 yds, one at "zero" and the other 20 clicks higher.

Working out the difference, the scope is 5mm per click. Someone of my expererience should have copped this sooner.

Thanks for all the help lads. Ye all made me think, which is a good thing.

Adjustment per click / 100 yds

1 cm
0.36 inch

5mm 0.18"
If you zero @100 yards not metres!

The old Battle Imperial Vs Metric!;)

tfox

Jonty wrote: »

update - did Edi's suggestion of firing 2 groups at 100 yds, one at "zero" and the other 20 clicks higher.

Working out the difference, the scope is 5mm per click. Someone of my expererience should have copped this sooner.

Thanks for all the help lads. Ye all made me think, which is a good thing.

Does this still explain why when you're zeroed at 100 yds your shots are falling 10 inches low at 200 when it should be more line 2.5"

garv123

tfox wrote: »

Does this still explain why when you're zeroed at 100 yds your shots are falling 10 inches low at 200 when it should be more line 2.5"

he never said they were falling 10 inches. he said they were 14 clicks lower.
14 clicks 7cm which is bout right

tfox

Jonty wrote: »

When I zero at 100, I'm striking about 10 - 11" low at 200.

Think he did say he was hitting low at 200 from 100 zero :rolleyes: