I asked this in the barrels,uppers & lowers section, But I wanted to get an opinion from the experts.
I hope I can explain this clearly.
I have a new 10.5 upper and a new bolt/carrier group. The bolt is a Colt and the first thing I did was replace the extractor spring in it with a Wolf XP. Upper and lower are not put together yet, and I was playing with some snap caps and spent shell casings. Loading them in the chamber to see how they would extract. In order to get the bolt to latch onto the case rim I have to really slam the carrier home hard, real hard. This just doesn't seem normal to me because my well used 16" upper grabs on to the case rim with no effort at all.
I don't know if the 10.5 is like this just because everything is new or maybe I need to remove the XP spring and reinstall the original extractor spring. The extractor is marking up the case rim a little too.
Should I just go with it the way that it is, or is this not a good situation?
On the SBR using either a wolf extra power spring, or a D-fender, the increased tension on the extractor is going to make it hard to hand lock it over the case rim. Under the recoiling power of the buffer and receiver extension spring, the bolt/extractor will have no problems riding over/locking onto the rim.
To add, if your setting up the 10.5" for a MG, you really need to get an H buffer or heavier to control bolt bounce and delay the bolt unlock cycle. Also, helps to hand polish out the chamber since the case is going to be under more than normal pressure during the extraction.
P.S. I'll be back in Denver in a few months if you are having problems getting the SBR/MG to run, and need some help trouble shooting it.
Thanks for your help. Sounds like I'm worried for no reason.
BTW SBR will be used in semi only(at least for the forseeable future) and it does have an H buffer.