Knight's SR-25 Buffer Tube Removal Problem

[Fire4EffectCA]

I have an early Knight's SR-25 that has a buffer tube that so far have proven to be impossible to remove. This is a very early rifle and one of the first 100 manufactured in 1993. I have tried the following:

• Applied acetone to the threads for several hours with no effect. It appears to slowly penetrate, but my be just evaporating.
• Applied Kroil to the threads for several hours with no effect. No penetration.
• Applied heat with a heat gun set for 600 degrees, but was not able to raise the temperature of the buffer tube and lower receiver much above 200˚F. I believe the aluminum is just conducting the heat away. There is no way I will consider applying heat with a torch to the buffer tube or lower receiver.

The lower receiver is secured in a vice at the pistol grip mounting boss and protected with heavy leather. I use a vey large adjustable Crescent wrench to apply turning torque to the buffer tube.

I did extensive reading on the Internet and there is a lot of history of buffer tubes frozen on lower receivers and the culprit is frequently Loctite. Does anyone know if Knight's used Loctite for their installation of buffer tubes on early SR-25’s or might this be a case of frozen threads due to lack of assembly lube?

 

[Badshot308]

I have an early Knight's SR-25 that has a buffer tube that so far have proven to be impossible to remove. This is a very early rifle and one of the first 100 manufactured in 1993. I have tried the following:

• Applied acetone to the threads for several hours with no effect. It appears to slowly penetrate, but my be just evaporating.
• Applied Kroil to the threads for several hours with no effect. No penetration.
• Applied heat with a heat gun set for 600 degrees, but was not able to raise the temperature of the buffer tube and lower receiver much above 200˚F. I believe the aluminum is just conducting the heat away. There is no way I will consider applying heat with a torch to the buffer tube or lower receiver.

The lower receiver is secured in a vice at the pistol grip mounting boss and protected with heavy leather. I use a vey large adjustable Crescent wrench to apply turning torque to the buffer tube.

I did extensive reading on the Internet and there is a lot of history of buffer tubes frozen on lower receivers and the culprit is frequently Loctite. Does anyone know if Knight's used Loctite for their installation of buffer tubes on early SR-25’s or might this be a case of frozen threads due to lack of assembly lube?View attachment 7612315

I would just contact Knights Armament directly and ask for their advise.

 

[GH41]

Why are you trying to remove it?

 

[Fire4EffectCA]

I would just contact Knights Armament directly and ask for their advise.

It's unlikely anyone there remembers how this rifle was assembled 28 years ago. If the buffer tube can't be removed with normal service procedures I will not attempt to go any further.

 

[Fire4EffectCA]

Why are you trying to remove it?

I decided to upgrade the buffer spring to a Tubb’s SR-25 Flatwire Buffer Spring. I talked with another owner of an early SR-25 and he only changed the spring and not the plastic buffer. Unfortunately the combination of the solid plastic buffer and the flat wire spring would not pass over the buffer retaining pin and could only be installed by screwing the spring in. This process removed all of the factory applied solid lubricant on the spring as it rubbed against the buffer retaining pin and created a mess. I have easily removed the buffer tube on other AR’s and decided to remove the buffer tube on the SR-25 to inspect and clean.

 

[msgriff]

Pack the RE with dry ice, plug the end and try to keep the hub warm with a rag moistened with hot water. I would consider making wooden vise blocks to match the angles of lower receiver RE hub and clamp there because, you know, it's a Knights, not a PA-10.

 

[Fire4EffectCA]

Pack the RE with dry ice, plug the end and try to keep the hub warm with a rag moistened with hot water. I would consider making wooden vise blocks to match the angles of lower receiver RE hub and clamp there because, you know, it's a Knights, not a PA-10.

Thanks for the suggestion, but I have already put the old girl back together. I gave the buffer tube a good cleaning and installed the Tubb’s flat wire spring. That was brutal getting that in. I also installed a 5.3 ounce buffer from Clint at Heavy Buffers. I am looking forward to see how she shoots.

 

[weekend_warlord]

How does it shoot??

 

[Fire4EffectCA]

How does it shoot??

Shoots great. Perfect extraction with the 5.3 ounce buffer from Clint at Heavy Buffers and Tubb’s flat wire spring.

 

[weekend_warlord]

Shoots great. Perfect extraction with the 5.3 ounce buffer from Clint at Heavy Buffers and Tubb’s flat wire spring.

Awesome!! Glad to hear, planning to try out the same combo! Thanks for the update