Learning MOA Adjustment

[Elite Muzzleloader]

Took my 45 McRem Smokeless Muzzleloader out this morning. It's shooting around 2700fps shooting a Parker Ballistic Extreme with a BC of .250 (book BC is .267). I'm using the Strelok Pro App to calculate adjustment.

My question is once I put all the info in it told me 9.5 moa adjustment for elevation and 2.75 moa adjustment for wind. I did not adjust for wind with the first three shot group to see the affect of wind. Elevation was still 1.5 moa low and the wind correction was very close to being right. I made the elevation and wind correction but added a little to the wind adjustment. The wind adjustment to me was correct however the elevation was off. I thought the BC was of but then it recorrects the wind adjustment also. I'm wondering if the chrono is not reading correct and if so do I back the info down in the app to get correct elevation adjustment?

 

[Elite Muzzleloader]

So I just got done doing some research and now I wonder if this is the issue. The scope I have has a total of 55 moa adjustment with that said where it's sighted in I only have 15 moa left for adjustment. What I read was because I'm at the end of my adjustment the spring has more pressure on it causing it to not track as accurate, would this be a correct statement? Should I get the offset rings by Burris and get around 30 moa back?

 

[blacknzr1]

theres lots of reasons why. and only really you can find out for your particular application.
maybe the crony was having a bad day.
maybe your inputs to the ballistic app were not accurate.
hows the e s on your ammo.
maybe the clicks on your scope arnt a true 1/4 moa at 100

the list goes on. you need to verify your drops in the real world like your doing.
you could adjust the velocity or b.c a bit to get everything to line up.

good luck

 

[Elite Muzzleloader]

I have another question. The scope I have has 55moa total adjustment in the scope. I'm sighted in at 200 yards which pours me at the 40th moa mark. So I only have 15 moa left in the scope for elevation. I read that if your in this area of the scope because it's at the end per say of its travel the tracking is not as true. Is this a correct statement?

 

[blacknzr1]

If its a good quality scope it should be ok. but if you want more adjustment or your worried about it this is where a canted base comes in. or canted rings, or a shim of some kind to get that adjustment back. if for example you used a 20 moa base then re-zeroed you should have 35 moa left to use.
I use a canted base and burris signature series rings the ones with the plastic inserts. I like them a lot you can change the amount of cant and they hold tight without marking the scope tube.


I hope that helps.

 

[Bigcat_hunter]

Make sure your scope height above the bore is entered correctly in your ballistics program. That will get you. Usually by default they are 1.5" but rarely is that correct.

 

[Wachsmann]

So on the scope height is it measured from the center bore of the rifle to the center of the cross hairs?

 

[Bigcat_hunter]

So on the scope height is it measured from the center bore of the rifle to the center of the cross hairs?

Yeah. I take my calipers and first measure the scope tube then the bolt diameter and divide in half(each). Then I measure from the bottom of scope (at the turrets area) to top of the bolt. Then add the 1/2 measurements of the bolt and scope to get the correct height. Sounds confusing but its pretty simple.

 

[7magcreedmoor]

It is possible for a scope's adjustment increment to be changed slightly as you near the edge of the envelope internally, and also for the actual increment to be slightly off spec from what is published. Test yours by using a tall target and aiming at the very bottom of a vertical line, adjusting up 10 moa for each shot. If your turret gets funky toward the limit, you'll see it happening on the paper. You also can measure the actual distance between shot groups as you go up, and calculate the "true" increment of your turret adjustment. The angled scope base and or use of Burris rings with inserts can get you closer to the optical center of your unit if that turns out to be the main issue.

 

[johnnyk]

Are you imputting your BC as a G1 or G7? JohnnyK.