.22lr through 1:7 twist barrel

[Neeglik]

Due to ammo cost and range considerations, I'm debating on going with a .22 conversion for my AR.

I know the accuracy in a 1:7 or 1:9 won't be as good as a 1:12 or a 1:16, but how bad are we talking here? I'm going to be shooting 25yds at most and I'm happy with fist size groups. Can I get that from the 1:7 barrels?

[bigbore]

it will foul up quick.

[Neeglik]

By foul up, do you mean make the gun dirty, or foul up my groupings?

[Submariner]

Not to put words in bigbore's mouth but I think it means lead fouling (and, perhaps, unburned powder).


The .22 conversions available for them tend to be
cranky, unreliable, inaccurate and a beast to clean. There are two
reasons for these problems. One, the centerfire bore is supposed to
have a nominal diameter of .224-inch, while the .22 Long Rifle bore
is supposed to have a nominal diameter of .221-inch. Those three
thousandths of an inch do matter.

And second, the slowest twist in an AR barrel is one turn in 12
inches. A proper rimfire bore has a twist of one turn in 16. The too fast
12-inch twist, combined with the loose bore, means casual
accuracy. (You can imagine what the one in nine or one in seven inch
twist rifling some AR barrels have does to a soft rimfire bullet.)

[deadwood83]

I was debating doing the same thing as you (except I have a 1:9) and borrowed a neighbor's conversion kit. In addition to crazy innaccuracy the cheapo 36 HV stuff I had didn't make it 25 yards before it turned into a puff of lead.

Upon return to home I really looked at the mess in the barrel. Rather than toil for hours on end with a brush and CLP I broke out the .50 solvent, ammonia, and the pressure washer. (needless to say my cleanings take place out doors:D )

If you want to shoot .22 then get a dedicated upper. The most accurate SA .22lr i've seen (excepting some insane 10/22's) was an AR with a dedicated upper.

The biggest cost factor will be the barrel. If you do go this route, I believe I saw a fine looking Anchutz blank that Numerich had for 90 bucks or so.

good luck