When installing a Bushy barrel onto a RRA upper w/ RRA bolt/carrier assembly should I expect headspacing problems?

Normally the complete barrel and barrel extension set-ups assure headspacing will be no problem, but it doesn't hurt to check the headspacing upon assembly with either a haedspacing guage or field "go"/"no-go" guages.

FWIW, new complete barrel assemblies I build get "new" bolts, if not complete b/bc/ch assemblies, as I don't mix old parts and new. That said many have and do use old bolts w/ new barrel or vice-versa and incur no problems. Always use guages to verify the headspacing should this be your SOP.

The fact that I don't mix parts is my personal preference, YPPMV.

Mike

What mr_wilson said.

FWIW, I've got a RRA A3 upper with a Bushy government profile barrel and haven't had any problems.  It headspaced fine.

Not [i]normally[/i] but [b]always[/b]:  Headspacing is determined solely by the relationship between the barrel extension (a permanent part of the barrel) locking lugs and the bolt locking lugs.  The upper receiver doesn't enter into this at all and you can confirm the headspace before you install the barrel in the receiver.

The major problem is there are no gages.  No gages which mean anything anyway.  Commercial ".223" gages are severely undersized and it's possible that you can get the bolt to close on a .223 Field Reject gage when the rifle meets GO spec.  Chambering a commercial GO gage can result in a severely undersized chamber, so it means nothing either.

There is one (1) gage you can use, it's the M16 Field Gage and is available from varying sources.  Instructions on how to use it are in the -23&P, the same manual with the instructions on how to do the rebarrelling.

But if you have a new Bushmaster (or Colt's) barrel and new bolt the rifle will "headspace" right out of the box as these parts were gaged at the factory.  Use the M16 Field gage if you want, but it won't chamber.  No point in bothering with the commercial .223 gages as they tell you nothing.  If a 5.56mm cartridge chambers the headspace is long enough.

-- Chuck

If I were to take my my 16" Bushmaster rifle with A2 reciever and replace that reciever with RRA flattop reciever but keep the same bolt and barrel from my Bushmaster, would I have any problems?  I assume because the bolt and barrel came together in my rifle that I would not have any headspace problems.  Is this the case?

Steve

Correct you'd have no problems whatsoever headspacing wise.

Mike