Buzzard Posted June 27, 2012 at 11:35 PM Posted June 27, 2012 at 11:35 PM I know we have a recent AR15 22LR conversion thread, but I didn't want to hijack it for my purposes so here goes.... I'd like to take an AR15 to the Appleseed shoot and was pondering the twist rate of an AR and how they perform with .22LR ammo. I have a friend that has offered his AR with a handle mounted scope and will also supply a Colt .22LR conversion. He noted that his AR performs best with CCI Stingers, as lesser powered rimfire ammo doesn't have the poop to feed semi-automatically. I went to the CCI webpage for Stingers and although they give performance and trajectory figures - they don't give the rifle specifications to match those figures. What is the best twist rates for this ammo? What rates do the AR15 22LR manufacturers use? The website said Stingers have a 32 gr. bullets - which is roughly half that of 55gr. .223 rounds have. We'll be bringing a Marlin .22 scoped rifle along as a primary gun and also the AR for a special treat. I may even join in the fun if we can afford it! I'm trying very hard to have the equipment right, so as to not hinder the grandson and ensure that he comes away having had a very good experience and learned something too. And I hope he has a nice memory of a couple days well spent with his grandpa.
AFigmentOfYourImagination Posted June 28, 2012 at 01:28 AM Posted June 28, 2012 at 01:28 AM Upon further reading and trying to figure out if there was a uniform standard it has become clear to me that the vast majority of places that make 22lr uppers for AR15's use a 1:16 twist and as best as I can identify a .221 internal barrel diameter. The .223 barrels have an internal diameter of .224 One place stated that they use a 1:16 twist to efficiently handle the wide variety of ammo...or something to that effect. Being the friggin genius that I am (sarcasm alert!) I searched using different verbiage 4 times to ensure I came up with what I was looking for....and then read a bunch, closed a few, and wound up closing the one with that description. And now I can't remember what search terms I used nor what link it was that stated such! One thing I've figured out in all of this....it's damn near impossible to find a dedicated 22 lr upper for an AR15 for a cheaper price than you can go buy a respectable 22 (Remington 597, or Ruger 10/22).
Buzzard Posted June 28, 2012 at 03:05 AM Author Posted June 28, 2012 at 03:05 AM Upon further reading and trying to figure out if there was a uniform standard it has become clear to me that the vast majority of places that make 22lr uppers for AR15's use a 1:16 twist and as best as I can identify a .221 internal barrel diameter. The .223 barrels have an internal diameter of .224 One place stated that they use a 1:16 twist to efficiently handle the wide variety of ammo...or something to that effect. Being the friggin genius that I am (sarcasm alert!) I searched using different verbiage 4 times to ensure I came up with what I was looking for....and then read a bunch, closed a few, and wound up closing the one with that description. And now I can't remember what search terms I used nor what link it was that stated such! One thing I've figured out in all of this....it's damn near impossible to find a dedicated 22 lr upper for an AR15 for a cheaper price than you can go buy a respectable 22 (Remington 597, or Ruger 10/22). Yup. I found some .22LR uppers at Brownells. And they were a twist rate of 1:16. My next question is - just how much is the accuracy adversely affected by just using a conversion bolt/magazine in an otherwise stock AR?
sleepercaprice1 Posted June 28, 2012 at 08:17 AM Posted June 28, 2012 at 08:17 AM It's going to be difficult to quatify how much accuracy will suffer, but I think one can safely say that a rifle with the proper bore diameter and twist rate will probably be more accurate than one with an oversize bore and too fast a twist. That being said, I my limited experimentation, I found that a slower twist 1/12 barrel is more accurate than a 1/9 or a 1/7. Of course, that is with a very limited sampling and should not be considered proof by any means. None of my AR's with the CMMG kit are nearly as accurate as my 10/22 with aftermarket heavy barrel. If I planned to shoot .22 rimfire regularly, I would buy a different upper with the correct bore diameter and twist rate or else I would just buy another 10/22.
Recommended Posts
Archived
This topic is now archived and is closed to further replies.