so i have seen this kind of post all over the forums and other forums. yes i know, “why post another thread then?” the reason im posting is because there seems to b a wide variety of opinions. some say just the conversion kit works great in their 5.56 and .223. where others are saying that their barrels are being destroyed from just using the kit. ive also heard of cases where the twist rate is incorrect.
if this is the case then y not just buy the 22lr upper? or should every1 jus get the conversion?
The conversion unit is cheaper, <$200, generally less accurate (say 2" at 25yds with bulk ammo) and a bit dirtier than the a complete rimfire upper. I use a conversion kit.
Does it work in my 5.56 barrel? Yes
Is it accurate in a 5.56 barrel? If you consider hitting a paper plate at 50 yards accurate, then Yes.
Is it destroying my 5.56 barrel? No
I don’t use mine for pinpoint accuracy, for me it’s used to reset the hammer. A dedicated .22lr upper would surely be more accurate if that’s what your looking for.
Isn’t the twist rate for a .22LR somewhere around 1:15. Ar’s are 1:7 to 1:9. Plus the velocities of the two cartridges are different by 1400 fps or more. Might not give the best groups. Don’t put 87 octane in a Corvette.Go with the upper that is designed for the cartridge.
True, the twist rate of an AR is optimized for a 5.56/.223 bullet and you won’t get the best groups with a rimfire round. That said, there is no harm in using rimfire ammo in an AR conversion kit if you are satisfied with the 2" groups. The rimfire bullet will expand to obturate the bore just fine. And, unlike putting the wrong octane fuel in a car, it will cause no harm to the AR.
An interesting bit of personal experience: While Federal 40gr. hv. ammo gives me the aforementioned 2" groups, Aguila 60gr. Sniper Subsonic gives me .25" 5 shot groups at 25 yds. and functions flawlessly.
I chose the conversion kit route over the dedicated upper because my goal was the least expensive route to increase trigger time with 2 ARs. One has an ACOG on it the other an Aimpoint T-1. I didn’t want the extra expense of duplicating either optic or the hassle of swapping them back and forth + re-zeroing each time I want to use rimfire.
With a conversion kit it takes less than 1 minute to switch and I get the same optics, weight and manual of arms of centerfire.
That is good to know. I have looked at a conversion kit myself, but was afraid the bullets wouldn’t group well because of the difference in twist rate combined with the difference in velocity. I can see where a 60gr. bullet would do well in a 1:9 twist verses a 40gr. Just thought it needed the fps to give the best results.
All three are very good choice and I’ve owned or have used uppers from these three companies in/for builds for customers.
Velocity is the least expensive at under $400 and has a polymer receiver. While in a full on AR this would be a “not optimal” choice to build an upper from in this case it seems to be ok. My wife has a Velocity upper for her AR and has put better than 12k rounds through it in the last year and half with no problems. ( There IS a break in period where it does all those fun things we hate about .22s, FTF and FTE out the wazoo for the first 2-300 rounds.)
Tactical Solutions is the accepted “benchmark” for .22lr accuracy. (even though they are a tad pricey and have a rep for being finicky about ammo. Personally haven’t experienced that problem myself.)
Spike’s has a very loyal following as well with a price point just below TacSol’s. (According to everything I’ve heard and personally seen these things will eat anything you feed them.)
Basically it’s a Mama,Papa, and Baby Bear sort of thing. Just need to find the one that’s “just right” for you.
I built a dedicated .22LR AR last year using a Spike’s bolt and a custom barrel from Ballistic Advantage. (BA is the vendor Spike’s uses for custom profiles - I wanted a LW, not an M4 profile.) I put them on a BCM upper and a caliber-marked AGP Arms lower.
It’s been great from day 1 - I’d do it again with no hesitation. I see 1" groups at 25 yards with bulk grade ammunition from Walmart, it’s probably capable of better with top grade stuff but I haven’t tried. Reliability has been 100%.
If I were building another from scratch I’d seriously consider using CMMG’s bolt, they’ve made quite a few advances this past year. But I’m not going to replace my Spike’s-based build.
Nordic NC22. AR on the outside, 10/22 on the inside. They designed the system like a 10/22 with a heavy bolt to improve reliability. 10 million 10/22’s can’t be wrong.
Takes Ceiner/Atchison/BDM/CMMG magazines, and 10/22 extractors (if you’d ever need to change one).
They are running a 10% off special until the end of the year. Also can be ordered without their FF tube for an additional $40 off. Great if you happen to have some spare parts laying around like I do. Got my upper for $413 shipped, and plan on putting a Troy TRX 11" on it.
CMMG stainless conversion or CMMG dedicated upper.
Uppers start at $350
Mine has over 6000 rounds down it with 3 fte’s.
Live round extraction, forward assist, bolt hold open.
Match barrels available.
My blaster barrel shoots .807 at 50 yards with EleyXSP.
1.2 at 50 with CCI Mini mags.
1.29 at 50 with Winchester 555.
I have 2 TacSol uppers - an M4 and an LT. Neither are finicky about ammo and both are tackdrivers. They are finicky about custom triggers though.
I have a Nordic NC22 upper. It is accurate, not finicky about ammo or custom triggers. Not quite as accurate as the TacSols.
I have a CMMG M4 with a stainless steel bolt. It is extremely reliable, not picky about ammo or custom triggers. It is the least accurate of the 4, but not by much. It was also the least expensive and has features available that the others do not.
I’d say you can’t go wrong with any of these dedicated uppers and all will beat the 2" groups of the conversion kits.
I’ve never noticed any wear on my chambers or barrels. Mine are chrome lined.
I would use CMMG mags with a CMMG jit if you are going to use the BHOA. If not, BDM’s work fine.
CMMG is also coming out with modular mags.
CMMG has great CS. I had a chamber adaptor crack on my kit. I e-mailed them and within 10 minutes they e-mailed me back letting me know that they had one in the mail for me. 2 days later, GTG.
You had one of the old chamber adapters. New ones are machined from a solid piece.
I’ve seen how they deal with customer service since I’ve been testing for them and it’s top notch.