rcmodel, the 550 Remington used a floating chamber to get anything from shorts to long rifles to feed and function the action, the 552 does not.
The 552 uses a "Progressive load" action spring and receiver buffers to control the bolt recoil bounce allowing it to function with any kind of .22 rimfire excepting Stingers (Too much) and CB longs and shorts (too little) though these low power loads can be hand cycled through the action.
Destructo6, My experience with 552 Remingtons is quite the opposite.
The guns tend to feed just about anything if they are kept clean and properly lubricated and there lies the problem.
The rifles are not well suited to average shooters as detail cleaning involves quite a bit of pulling apart and putting together to really get all of the gunk out of the action.
I have detail cleaned several of these guns and three faults I have seen can cause the rifle to malfunction.
1. The "progressive load" action spring (This is how a Remington Rep explained the spring to me so bear with me) becomes kinked, mashed or bent.
Replace it with a Remington OEM spring.
2. There is a rubber bolt buffer in the rear of the action that can become beat up, cracked, or simply breaks apart due to harsh chemical cleaners. Replace it with an OEM Remington replacement buffer.
3. The internal action becomes so filthy it simply cannot function as intended (Most common ailment)
Keb, I am going to be brutally honest here.
If your professional gunsmith really was filing on existing internal parts and not stoning some OEM replacement parts to achieve a perfect fit, he flat out did NOT know what he was doing and your best and greatest solution to the function problems would be to send the gun back to Remington or an authorized repair center for evaluation.
