AR Buffers, Buffer Tubes, and Springs Question.

[CraigAPS]

So, I purchased a PSA build kit to assemble my INGO lower. I ended up buying an MOE stock from a fellow INGOer to use in lieu of the standard M4 stock. The MOE stock came with a buffer, buffer tube, and spring (It was a good deal. So, I thought "What the heck. I'll have extra parts"--which are slowly turning into another rifle, but that's a different story.). I just assembled the lower with the build kit and switched out the stocks. "No big deal," right? Well, the MOE stock was a little loose on the buffer tube, and the M4 stock was really tight on the buffer tube from the MOE deal (I put it on there just to save room. It was tough to get it on.). Today, I switched the buffer tubes out. Both fit into the lower fine. They are the same length. Neither has an angled back end. So, it's not as though one is commercial and the other is mil-spec. What would account for the difference in thicknesses? The buffers and springs both fit in both tubes. The buffers seem to be the same weight. I don't have a scale that I can weigh them on to be certain. The spring I got from the INGOer is about an inch and a half or so longer. Will this be an issue? I'm planning on taking both buffers and springs with me when I test fire it to see which combination works best. I have to get the BCG, still. Some bills came up that I hadn't planned on. I'll be able to get it in the next few weeks, but I just wanted to see what the brain-trust that is INGO might know about the buffer tube/buffer/spring issue, in the meantime. Thanks!

 

[Cwood]

For the tubes, there were commercial tubes made without the slight taper on the back of the tube. The best way to check is to actually measure the tube diameter with a dial caliper.

Commercial Tube Diameter 1.168

Mil-Spec Tube Diameter 1.148

 

[CraigAPS]

For the tubes, there were commercial tubes made without the slight taper on the back of the tube. The best way to check is to actually measure the tube diameter with a dial caliper.

Commercial Tube Diameter 1.168

Mil-Spec Tube Diameter 1.148

PSA - 1.146"
INGOer - 1.150"

I guess that's why the stocks don't fit the same. I had never measured them. I thought, as both fit just fine in the lower, that they were the same diameter.