hi,
have a question about these. i seem to have misplaced 2 of the 3 spikes tac. dedicated conversions i had.
what i was needing to know is does the dedicated units/collars of the cmmg`s match up
with the barrels of the spikes .22 bbls?

if not, i`m going to have to purchase 2 cmmg bbl`s & dedicated kits.

thanks for any info.

I have cmmg ones in my 22s that you can try if you are close by

sent im

The Spike’s Tactical collars and barrels are .500”.   The CMMG Barrel and collars are .460” diameter.   The only source might be TACCOM 3G, Velocity Firearms or Model 1 sales.   At one time these three vendors sold barrels with .500” barrel stub.

does the stub have the same extractor cut-out & in the same place as the spikes bbl`s if you know?

i`ll give these people a call soon

M1S is about the only place nowadays. Gotta call, though; they don't show it on their site. I think it's ~$40
Velocity, if I'm remembering correctly, bought the rights from another company. I think they only did some short runs and stopped making them. They used to be made from Delrin as well, for a quieter function.

ETA: I believe all the .500's are made the same, but not all the .460's

I’m pretty sure the extractor is in the same location whether Spike’s or CMMG.  There are forum members use Spike’s bolt with CMMG barrels or vice verse, CMMG bolt with Spike’s barrel with the appropriate collar.   I looked on Velocity firearms site, TACCOM3G and Borbuddy and no list the .500” collar.   I looked on Model 1 Sales website and the collars or dedicated bolts are not listed so you need to call them.   Another thing you could do is use the chamber insert and have it machined to fit a .500” barrel stub.   This was very common when people started building their own dedicated uppers before Spike’s entered the market.  Rick Kuehl manufactured dedicated uppers which used the Ciener/Atchisson pattern bolt.   A few barrels were made and adapted to Ciener bolts.   Ciener was the popular AR-15 22 LR bolt because Ciener sold a 30 round metal mag.  At that time in the 90’s all the other AR-15 22 conversions only had ten round mags.

good info...thank you!

Here is a link to a CMMG chamber insert.   You can mill off the cartridge looking end and drill out the body to fit the .500” barrel stub.   The CMMG collar could be drilled out but it has a retaining detent to go into a groove in the barrel stud for retention.   I think in the end it would be easier to modify a chamber insert than modify a collar.   Since you don’t have the bolts you could buy to CMMG conversion bolts and modify the chamber insert.



https://www.righttobear.com/22lr-conversion-chamber-adapter-rtb-22ba45c/


Unlimited Arms has their 22 LR AR-15 and conversions on sale and might be an option.  One of the cheaper options currently on the market.   I just realized the conversion kit has three fifteen round CMMG mags which are the same length as the 20 round 5.56 mags.   The Arms Unlimited AR-15 22 LR conversion mags are 25 round and are $9.   PSA has the CMMG conversion kit in stock but more expensive.


https://armsunlimited.com/cmmg-22lr-conversion-bolt-for-ar15-w-3x-au-15-round-magazines/


https://armsunlimited.com/au-25-round-.22lr-conversion-kit-magazine/


https://palmettostatearmory.com/catalogsearch/result/?q=ar-15+22+lr+conversion

a lot of good stuff to chew on...thanks again everybody! be doing some research & calling soon.

first, gonna see if anyone has a couple of dedicated spikes conv. on here. might pay high & maybe not.

As I said, call M1S. They sell them, jut not listed on the site.

Also, it makes more sense to have your barrel stub turned to .455, if you're going to machine anything. You'd be able to use .460 collars.

makes sense, thnx

I recently purchased a collar from M1S.  After shipping it was $40.95.  This one replaced a collar for an early version of the Taccom3G barrels that has a damaged feed ramp.  It works perfectly.  I had to call M1S, I couldn't find any way to purchase it on their website.  I purchased collars from Velocity in the past but they are no longer offering them.

The diameter is one thing but the length of the stub is also a consideration.  I'm pretty sure the collar I purchased from M1S is 0.500" long by 0.500" dia.  The collars and barrel stubs offered on the market now are 0.460" dia x 0.700" long.  Taking care to keep it flat, one could sand the backside of the collar to 0.500" but I don't think I'd mess with the stub as it is.  Just get a collar.  

I wonder if RennaissanceMan would be able to make some collars with these old dimensions.

The dimension from the upper receiver face to the end of the stub must follow a standard/spec, regardless of collar size/length. If more needs to be taken from the breech extension, so be it.

I've considered it, but it seems to be a pretty small market.  We always recommend people re-barrel for parts compatibility going forward.  There are some really nice barrels available these days!

update...good news. found a complete bolt assy. also, found one of the ones i thought a had misplaced!!

i`m happy now.

thanks all for the good info!

Very good news.   Glad you’re in business without a lot of expense!    Thanks for letting us know!