It's not always easy to find a long range to zero your carbine. But, if you can find an indoor range that will allow rifles, you can confirm your 50/200 yard carbine zero at 10 yards. This will allow you to check your carbine after any changes you’ve made recently, especially in the winter months when inclement weather can make going to an outdoor range less than appealing.
Here’s the quick and dirty:
Setup a target at 10 yards or 30 feet.
Assume a stable position and fire 3-5 rounds on target
Check your results
Adjust your sight(s) and repeat until you achieve your desired results.
What you’re looking for is the rounds to be roughly 1.8"-2” below the point of aim. This should have you very close to your 50 yard zero on your carbine. Be sure you double check your carbine at 50 yards when you are able.
There are targets available with 1" grid patterns specifically for sighting in rifles like the target above. These are really helpful when trying to get that 2" offset from the point of aim to the point of impact.
If you want to get more scientific, use JM Ballistics' free calculator to find out what your rifle ballistics are doing more accurately.
Found on Frank Proctor's Youtube