AR15 .22LR adaptor query

[kBob]

I have seen in a Blue Press catalog an ad for a spacer that is placed in front of the buffer assembly inside the buffer tube that supposedly improves the reliability of .22 Adaptors such as the old CObrays and ceiners etc.

Do these actually work and if so why?

How much difference can it make?

Can I get the same results from compressing the buffer spring by simply dropping say a section of broom stick handle down the tube and then inserting the buffer and spring?

-kBob

 

[Jackal1]

I haven't seen those spacers... but I have a conversion and the only thing I can think a spacer would do would be when chambering, to push the conversion a little harder into the chamber. The forward end of the conversion floats, so maybe they hope with an ever so slight extra pressure the floating part will center more reliably with the barrel....

Sounds like a product in search of an answer. I haven't looked up the exact bore diameter in comparison to the bullet diameters, but I have heard that the .223 rifled barrel is ~0.001" larger in diameter than the 22lr bullet thus the conversions are inherently inaccurate to begin with because the 22lr bullets do not seat properly into the grooves.

I'm probably wrong, but that's my 2 cents.

 

[VA27]

I have a Ceiner and it runs 100%, so I guess I don't need one.

 

[DBR]

The Ciener type conversions are a self contained blow-back mechanism. At the end of each recoil stroke the entire unit pushes back against the AR buffer. This can cause the unit to move in and out of the chamber slightly each time the gun is fired.

I have one of the spacers you are referring to and I think it does help to keep the conversion unit from moving in and out of the chamber.

There are better ways to do it IMHO. Yes, a spacer behind the action spring is one way. Another way if the rifle has a carbine length extension tube is to use a rifle length spring and/or a rifle buffer.

The one advantage of the spacer is you can see it and know it is a foreign part. It is easy to remove when you want to use the rifle without the conversion. The other methods I described risk forgetting to restore the buffer system to standard before shooting 223/5.56 ammo.

I don't think firing the rifle without restoring it to stock will do any damage but it will tie up the gun.

If you do use the spacer be sure to break the rear edge of the plate at the end of the conversion unit generously. Otherwise it will gouge and notch the soft nose of the plastic spacer when you close the upper.

 

[kBob]

Thanks to all so far. I am referring to mechanical reliability rather than accuracy.

My experience with Adaptors only extends back to 1979. I found the old Cobrays to be not as accurate in M16 A1s as when using 193 ball, but accurate enough to train the folks I was responsible for. At the time the main complaints were mechanical functioning and I found that in those days the main culprit was lack of cleaning. I am not talking about your rifle aut for an after noon of fun, but adaptors in M-16 A1s that are being used by numerous trainees one after another. I found mechanical functioning was greatly enhanced by pulling units off the line and replacing them with clean units while the originals were cleaned and then rotating those with the next batch etc etc.

Still there were and are the occasional ( or in the case of the latest adaptor I have from Oily Arms, frequent) "now what caused the thing to not fire?" Moments when it is clean, lubricated, properly installed, and using quality ammo. As I occasionally find light primer strikes on unfired rounds, I believe the unit is backing out of the chamber slightly and then the hammer is wasting part of its energy shoving the unit back into position......much as can happen with a dirty chamber in say a 10/22 or Marlin 60 stopping a round before the rim is seated on the breech face.

I have considered ordering one of the hammer springs made for use with 5.45mm uppers that has the umph to deal with former Soviet military primers, but have been concerned that this might cause punctured primers with US commercial ammo.

Thus the interest in the plug.....

-kBob