I was just wondering how well they worked? Do they have issues with out-of-battery kabooms?

ALL the AR-based conversions can OOB Kaboom, and they all HAVE. This is because there is nothing disconnecting the fire control system, unlike in a designed .22, like a 10/22 or a Marlin, where the hammer won't drop unless the bolt is fully closed or darn close to it.

Best way I've found to prevent these .22 OOB KBs is to learn what your rifle sounds and feels like when it's running normally. Usually, there's a small metallic sound or feel when the bolt hits HOME. Learn to pick up on that, and if you DON'T hear or feel that, stop shooting and check it out.

Keeping the chamber clean is also a good idea. Some ammo is better about this than others. I've run 500-800 rounds or more through both my DPMS and a M261 without cleaning and without any chambering problems.

When you open a new box or a new lot of ammo, pay attention to the first 50 rounds or so and see if they're chambering smoothly. If it's an out of spec ammo problem, it will usually show up long before 50 rounds have been fired.

And ALWAYS wear your shooting glasses when shooting these things.

Thanks Snake45, but I was actually more interested in how well they (DPMS specifically) worked from somebody that owned one -- I've been thinking about getting one. I noticed that some owners had posted that they were having problems with Kabooms. The reason I asked about the shell busting is that these newer 22 conversions and complete uppers use magazines with cheap plastic bodies that have a tendency to break when there is an out-of-battery bust. In some cases the extractor is also ejected. This can get expensive -- especially to replace a magazine.  I have M261 units, Air Force units and some Cieners and know about out-of-battery busts but all my mags are made of steel except the Air Force unit and it has a good solid plastic mag case. I only lost one extractor and that was on my 10/22 which by the way,  the replacement 10/22 extractor can be used to replace a lost extractor in the M261.

Quoted: Thanks Snake45, but I was actually more interested in how well they (DPMS specifically) worked from somebody that owned one.

All right then. When mine blew, it knocked a chip out of the plastic magazine but didn't otherwise hurt it, but DID launch the right hand extractor into parts unknown. Other than than, it's worked just fine.

Quoted: I was just wondering how well they worked? Do they have issues with out-of-battery kabooms? img.villagephotos.com/p/2004-11/877429/DPMS22drop_in.jpg

Did you just buy that drop in ? I don't see it on the DPMS web site. Your photo shows the long silver protrusion style I can't find.

Quoted: Quoted: I was just wondering how well they worked? Do they have issues with out-of-battery kabooms? img.villagephotos.com/p/2004-11/877429/DPMS22drop_in.jpg Did you just buy that drop in ? I don't see it on the DPMS web site. Your photo shows the long silver protrusion style I can't find.

hkusp,
To be honest with you I couldn't find the drop-in setup on the DPMS web site but I did find it on the Del-Ton web site and a couple of others for $124.95!
Go here; www.del-ton.com/detail.aspx?ID=1170

Snake45,
    Thanks for the info -- that's what I wanted. By the way -- what did the replacement extractor cost you?

I used to own a DPMS unit.  Despite the inherent inaccuracy of a drop in unit (any brand), it shot pretty well.  22 Thunderbolts shot fine out of it.  There was the occasional misfire, but that could just be the cheap brand.

The only OOB boom I had was using the Aguila SSS 60 gr bullets.  The extremely small and light casings of these bullets don't tend to eject well, and one got slammed in the bolt leaving about a 2 mm gap.  The shell exploded outward and took the right-hand ejector with it, and left a squib in the bolt extension.  Me = unhappy.

DPMS eventually sent me a replacement ejector free of charge, but good luck getting them to understand what part you want.  They actually sent me a dust door for the upper the first time, and several phone calls and 2 months later I got the right part.

Cheap conversion, though...

www.dpmsinc.com/10Expand.asp?ProductCode=BCBA-22M

I couldn't find it under the .22LR cal category, but a search for ".22LR" found it.  Picture shows a black chamber adapter.  I've never heard of a silver one or them being different.  In fact, I've not heard much about their drop-in ones at all.

BTW, how come a complete conversion kit with magazine is $130 but a replacement bolt, identical except for the chamber adapter and without the magazine, is $150?

Quoted: www.dpmsinc.com/10Expand.asp?ProductCode=BCBA-22M BTW, how come a complete conversion kit with magazine is $130 but a replacement bolt, identical except for the chamber adapter and without the magazine, is $150?

Thanks for finding that -- I quess I just don't have enough patience to continue looking for stuff. By the way -- notice DPMS's price -- I guess so they don't undercut their distributors.

I noticed the higher price for the modified unit that goes with their dedicated upper. I don't understand that either  -- I guess it's because it's extra machining. I wonder if any of the distributors sell the modified unit?

Quoted: -- notice DPMS's price -- I guess so they don't undercut their distributors.

I think most manufacturers would rather you went through a dealer/distributor than direct through them.  I've never really seen the kit anywhere besides the DPMS site.  I have noticed that the Ciener kit seems to be the same price no matter where you see it.  No discount through a dealer there.

I noticed the higher price for the modified unit that goes with their dedicated upper. I don't understand that either  -- I guess it's because it's extra machining. I wonder if any of the distributors sell the modified unit?

It's extra machining if they make the modified one from the others, but a lot less machining if they make them from scratch.  It's a lot easier to make a smooth-sided hole than a bullet-shaped protrusion.  

There wouldn't be too much demand for the modified bolt as a replacement part so I doubt many distributors would carry them.  If I had a failure that required replacing the whole bolt assembly and didn't hurt the adapter part I'd order a kit as the replacement, save $20, and get a free magazine.