AR15 22 conversion, sighting

[WhiteHot]

I am getting a spikes 22 drop in conversion soon and was wondering what most people do with their sights/optics when swapping back and forth between 223 and 22. I was running some trajectory models last night and for my setup, I found the following:
For 223, 50/200 yd zero optics had to be set around 6 MOA inclination.

For 22, 25/75 yd zero, it was around 13 MOA.

Obviously not even close. It seems pretty cool to be able to just swap out the bolt and blast away, but with my red dot, I would be shooting in the dirt. So do you hold over, adjust the sights, swap out sights?

[dieselpower]

If you are looking for a .22lr 50yard tac driver...a conversion bolt will not do it. I dont touch my optic and just adjust fire a "tad" when shooting at something about 50yards. With the wrong spin and my eyes + a couple cups off coffee I can get my .22lr spread down to 4" to 5" at a 50yard target. I am happy with that

[CHS]

Conversion units need to be used up close. They DO NOT have the accuracy for 50yards or further.

If you're looking to shoot those distances, get a dedicated upper like the TacSol and put dedicated optics on that unit.

[WhiteHot]

Not looking for a tack driver. I am OK with that kind of spread at 50. Just trying to get some ideas on getting the center of that group in the right neighborhood. When I get home from work, I will try to figure out how low I would be at 25 and 50 yd with the 22 if I used my 50/200 223 zero. Maybe the easiest is just a slight hold over...

[WhiteHot]

I am not looking for long range. I am going for a 25/75 zero for the 22 which will cover close in, out to 75 with a pretty flat trajectory. That's it.

[CHS]

out to 75 with a pretty flat trajectory. That's it.

You won't get that with a conversion unit.

[WhiteHot]

You won't get that with a conversion unit.

I wont get a relatively flat trajectory? The conversion bolt doesn't magically change the effects of gravity and wind resistance on a bullet.

I never said I was going for accuracy at 75 yards. For a 22lr round, the 25/75yd zero is one of the flattest shooting trajectories you can get within the effective range of a 22lr round. For shooting between 0-50 yards, that is pretty much the zero you would use with that round.

[ocabj]

I wont get a relatively flat trajectory? The conversion bolt doesn't magically change the effects of gravity and wind resistance on a bullet.

I never said I was going for accuracy at 75 yards. For a 22lr round, the 25/75yd zero is one of the flattest shooting trajectories you can get within the effective range of a 22lr round. For shooting between 0-50 yards, that is pretty much the zero you would use with that round.

First off, it's not a "flat trajectory". It's basically arcing with the same vertical plane at two distances, say 25 and 75.

But the two distances in which the trajectory will cross the same vertical plane is dependent on the muzzle velocity and the specific ballistics of the round being fired.

Ammunition varies, even .22LR ammo. You've got "high velocity" (supersonic) and subsonic (often dubbed match). Then you have .22LR designed for rifles and .22LR designed for pistols (powder and burn rates optimized for barrel lengths).

That said, just turn your elevation knob. That's what it's there for.

[WhiteHot]

First off, it's not a "flat trajectory". It's basically arcing with the same vertical plane at two distances, say 25 and 75.

What? I am talking about getting the flattest trajectory between 2 distances. Do you not consider the arc that a bullet flies in a trajectory? Small arc = realtively flat trajectory. Big arc = not so flat.

Elevation knobs on scopes are there for this type of thing. Elevation adjustments on something like an Aimpoint are primarily there for zeroing and not on the fly adjustments.

Still looking for creative ideas.

[killshot44]

Still looking for creative ideas.

Not too many people I know would be happy with a four inch group at 50yds with a .22.........

Conversions can be fun but look what you're building: A super-short barrel with too much twist. Most .22s have a 20"-24" barrel with a 1/14 twist.

Another rifle is a good alternative. You can pick up a nice used semi-auto for $200 on GB.

[WhiteHot]

Already have a 10/22. Already purchased the conversion. This is just for cheap fun. Based on the number of kits that get sold, it seems that people are happy enough with the accuracy they deliver.

Rifling in the gun it will be used in is 1:9 so it isn't great, but not as bad as 1:7.

Anyway back to the original question since I really dont want to argue about whether or not the conversion kits should exist...

What do most people do when they swap one of these kits into a rifle sighted in for 223?

[!@#$]

http://www.ar15.com/forums/topic.html?b=3&f=15&t=441890

read this to see what you can do with a conversion.

[WhiteHot]

Thanks for the link. I have come across that thread before and it is a great resources for 22 conversions. I couldn't find any info in it pertaining to swapping back and forth between the two cartridges though.

[WhiteHot]

Trajectory plots

I have my AR (with a red dot sight) sighted in for M193 with a 50/200 ish zero (blue line). I wanted to see what the trajectory would look like if I swapped in the conversion bolt and just shot some CCI MiniMags without changing anything. The result is in the plot below (red line). This is a plot of verticle POI vs height for a bullseye POA. Looks like out to around 50 yards or so, the POI would be around 2" low of POA and with a fairly flat trajectory. If the rifle was re-zeroed at 25 yards with the CCI MiniMags, the POI would be within 2" of the POA out to around 100 yards (green line).

I think I will just keep my 223 50/200 zero and hold over around 2" or so out to 50 yards with the 22lr.

*** I think the numbers I used in the simulation are pretty close but not exact as I didnt try dig too deep when looking for ballistic coeff and muzzle velocity for the rounds. Also assumes a 2.7" sight height.

[railroader]

When I shoot my conversion kit it's with ar that has a carry handle. I have the number of clicks for elevation and windage written down so I can pretty easily go back and forth between calibers. That's with both sighted in at 50 yards. Mark