Downside to a 22LR conversion bolt for an AR?

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Flakbait

New member
What is the downside to getting a 22LR conversion bolt for a 5.56 chambered AR? I know the twist rate of the 5.56 barrel (usually 1:7, 1:8, or 1:9) is not correct for 22 rimfire round. Does this lead to terrible accuracy or keyholing at rimfire distances say 50-100 yards. I see ads all the time for a conversion bolts made by CMMG for $150-200.

What kind of accuracy can you get with standard 22LR bulk ammo at say 50-100 yard distances with such a device. Are there any reliability issues?

Does 22LR ammo dirty up the chamber more then centerfire 5.56 ammo require more cleaning?
 
The accuracy is purported to be amiss in the conversions. The reason is that 22 LR bullets are .221 and the bore of your AR is going to be .224. Going to a dedicated upper for 22 LR is the only way around it.
 
the obvious...

1. the bullet diameter or the 22lr is .222", while the bullet diameter of the 5.56 is .224". so first off your looking at not making a proper gas seal as the bullet travels down the barrel. which can cause poor accuracy

2. the barrel twist the barrel twist for a 22lr is generally 1in16, while the twist for a 5.56 is between 1in7 through 1in14 with most being 1in9. so you will be spinning the 22lr too fast to maintain proper stabilization in flight. Which can cause poor accuracy [FIXED]

3. the gas system of the standard ar15 will get fouled by gasses that follow the 22lr down. And these gasses will be dumped into the receiver. the 22 conversion bolt is not gas operated but recoil operated. it is generally accepted that after shooting any amount of 22lr through your standard ar15 you should shoot a handfull of standard 5.56/.223 though it to "clean" your gas system.

4. the amount of cleaning? ... this is subjective since not everyone completely cleans their guns after every outing like i do, so i cant answer this. but it would stand to reason that you would have to take special care in cleaning the receiver.

5. jamming... my experience with ALL 22lr autos is that jamming is to be expected, and the conversion bolt will jam. but look at it like this: jamming is a good thing in that it makes you run through your stoppage drills

my personal experience is this.

i had a conversion bolt. i sold it and bought a dedicated upper. i get better accuracy with the dedicated upper. which i have since built into a full rifle.

22lr out of a ar15 platform is great! its way cheaper, quieter, and still fun. and it gives you the added opportunity for training
 
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I guess I should save up and get the dedicated 22LR upper. But then everyone will want to shoot it to I will then want another dedicated lower. So I guess I should plan to just buy another AR:)
 
Flakbait said:
I guess I should save up and get the dedicated 22LR upper. But then everyone will want to shoot it to I will then want another dedicated lower. So I guess I should plan to just buy another AR
Click to expand...

And the downside of that is? :D

As for the conversions, I remember my father ran a Ciener kit in an SP-1 years ago. I seem to recall the reliability being fairly decent and the accuracy somewhere around so-so. In the time since I've managed to try out a dedicated .22 upper and the accuracy was pretty impressive. Of course, it was a Compass Lake Engineering upper, so that was to be expected.
 
" the barrel twist the barrel twist for a 22lr is generally 1in16, while the twist for a 5.56 is between 1in7 through 1in14 with most being 1in9. so you will not be spinning the 22lr fast enough to maintain proper stabilization in flight. Which can cause poor accuracy"

So you are saying a bullet that is leaving the muzzle of a 1-16 twist is spinning faster than a bullet going the same FPS leaving the muzzle of a 1-9 twist?
You need to re-think this.
 
So you are saying a bullet that is leaving the muzzle of a 1-16 twist is spinning faster than a bullet going the same FPS leaving the muzzle of a 1-9 twist?
You need to re-think this.
Click to expand...

right... i put that in the wrong spot :rolleyes: i mean to say... the ar15 barrel will spin the 22lr too fast to maintain proper stablization... causing poor accuracy due to key holing/ tumbling

thats what i get for talking about engine building with one guy while typing about guns... a little cross mojonation
 
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