DPMS LR 308 lite 24"....height from middle of barrel to top of rail(For balistic purposes)

cerralvo78

Private
Full Member
Minuteman
Dec 13, 2013
15
0
Houston texas
Need to know the height in inches from the middle of the barrel to the top of the rail on my DPMS 308 24"

I have:
Leupold Mark AR MOD 1 3-9x40mm
AR-P.E.P.R. QD Mount


I’m using several apps and the one I like more is Ballistic AE


I know this is real important when making your calculations
1/2" off the height of the scope could mean POI about 2.5 off @ 400 yards from a 100 yard zero
Using .308 168gn Winchester Match ammo

I think I got my calculations wrong the first time I shoot it at 100 yards

First time I shot this rifle I went to a 25 yard indoor range and zero it at 25 and I think I measure 2.5 inches from the center of the barrel to the center of the scope...according to several ballistics apps:
When you zero at 25 yards scope height 2.5the POI at 100 yards should be around 5 inches....

Clean the rifle

AT THE 100 yard range the first 5 shots were about 9 inches high and not 5. :confused: (From sand bags)
Then I adjust it to center of target
After adjusting it was repeating groups on bull’s eye
After 30 shots the group drifted down to about 2 inches low (maybe about 35 shots it is what it takes to foul the BARREL???)
Then shot it for about 20 more time and it stay it there about .25 moa :cool:

Clean the rifle

Days later I took the rifle to the 25 yard indoor to see the POI after calibrating it at 100 yards
According to several apps the POI should be around 1.4 inches below POA.
From a Caldwell rest it repeatedly duplicated .25 groups at 2.00 inches below POI and not 1.4:confused:(did about 4 3 shot groups)

Maybe my scope height is wrong


playing around with the app Ballistic AE I change the scope height to 2.95 inches and everything closer to my actual shooting sessions ;);)

Ballistic AE input was zero at 25 yards scope height 2.95 output: POI 6.9 inches high of POA
The first time I shot it at 100 yards the total adjustment on scope was close to 7 inches high POA

Ballistic AE input was zero 100 yards scope height 2.95 output: POI 2.0 inches below of POA
The time I shot it at indoor 25 yard range I got groups at 2.0 inches below POA


any help or tips would be apreciate
 

xNF_9

Gunny Sergeant
Full Member
Minuteman
Jun 14, 2009
955
73
Fargo
I've tried to use this method before but when it comes down to it actual dope will be your best bet for getting the actual drop that you need. Don't worry what the computer says compared to what you actually get. Also, if you keep seeing huge POI changes you will want to check and see if something is loose on your rifle. Also if you don't have a rifle that has a free float barrel this can affect the POI also.
 

cerralvo78

Private
Full Member
Minuteman
Dec 13, 2013
15
0
Houston texas
I've tried to use this method before but when it comes down to it actual dope will be your best bet for getting the actual drop that you need. Don't worry what the computer says compared to what you actually get. Also, if you keep seeing huge POI changes you will want to check and see if something is loose on your rifle. Also if you don't have a rifle that has a free float barrel this can affect the POI also.

Thanks for your reply
I just need to get actual poi vs poa data and make my own ballistic data card
Thanks again