I know this has been discussed time and time again as I did more than my fair share of reading and researching, regarding the use of steel case/russian ammo in the RFB prior to trying myself. However I felt it necessary to post my own experience to perhaps help others avoid headaches. I recently purchased myself an RFB after lusting after one for years and have been experimenting with a variety of ammo I've accumulated for my other 308's, mainly hornady, remington, and Winchester of varying weights. Zero issues until after countless hours of reading, I decided to give some Tula a shot, given the significant cost savings and I had approx. 100rnds stashed away that a buddy had left at the house some time ago. I was looking to function check and set the gas for these, with the intention of buying a case to plink with. So...I loaded a single round into the magazine, inserted said magazine into the rifle, chambered said round, pulled the trigger and Bang! So far so good, looked and saw the bolt didn't lock back, so I gave the gas knob a few clicks, reached back to remove the magazine to load the next round and that's when I see that my magazine is blown to bits all over the ground. Ok...go to cycle the action...locked up... fantastic. Had already removed what was left of the magazine from the rifle. Was able to "finesse" action open and remove spent case. Upon inspection, found the primer was blown out and case head split and nearly separated. Mind you, this was the FIRST round of any steel/russian ammo to be chambered or fired through this rifle let alone any of my own firearms and will certainly be the last. I've always been one of those brass only guys and no longer consider myself an ammo snob after this experience. Kinda bummed out as I was looking forward to saving some dough with the 308 stuff but not worth risking the safety of myself or my firearms. I do want to mention that the ammo used was is excellent shape, had been stored in a dry box, not corroded, not previously chambered, was purchased approx. 3yrs ago. Was in no way externally/physically compromised. And after disassembling rifle, inspecting, and reassembling, rifle does seem to function fine with no visible or obvious damage other than some soot and debris around bolt and extractors, also noted excessive debris in bore but again, everything cleaned up. Unfortunately, that was my only magazine, so until I purchase more, which needed to happen anyhow, I will be unable to fire and fully verify proper function. Also glad I was wearing layers or my arm could have suffered some cuts or bruising.(I had noticed what seemed to be an abnormal thump to my forearm prior to realizing what happened...was wearing a thermal, hoodie, and Carhartt jacket)