My neighbor (and best friend) has recently purchased a never-issued Yugoslavian M59/66 SKS clone. It's the one with the NATO-standard muzzle grenade launcher, flip-up night sights, and a non-chrome-lined barrel. I completely disassembled the rifle for him and we tried to clean all the cosmoline using 125-degree Fahrenheit water, and apparently it was all cleaned off. However, when we went to shoot some rounds off in the woods, we found that the firing pin wasn't hitting the primer hard enough to fire. We only got about 5 rounds to fire. The ammo we were using was Wolf Military Classic 124-gr. hollow-point. My best guess is that there is cosmoline still left in there somewhere around the trigger group, and maybe some around the operating rod or gas tube as even when the gun did fire it didn't cycle. And yes, the grenade launcher gas switch was in the right position.

Anyone else have a similar experience or know what I can do to get this rifle working reliably? It's my favorite version of the SKS and we're both eager to take it to the range. We have a can of Break Free CLP that we're going to try applying to all the parts today, but I'm not sure that'll work. Any help would be appreciated!

Best thing I could say is take her apart and place the metal parts in a small bucket of gasoline or mineral spirits. Let the parts sit there over night and than scurb them down.

If you havn't done so already, disassemble the bolt and clean the cosmoline out of it also.

I had the same problem with an SAR-1. It turns out that there was a big glob of comoline in with the firing pin which made it stick. Also the extracor wouldn't grip the rim of the cartridge with out forcing the bolt foward.

Alright, we got it to work. My friend just soaked some of the parts in Nuts-Off solution, it did the job real quick. I also got him a black synthetic TAPCO 6-position stock with a pistol grip and Picatinny rail for his birthday. It's pretty fun to shoot, and works reliably so far. However, we only put 140 rounds through it, Wolf Military Classic 122 gr. JHP, Sellier & Bellot Czech-made FMJ, and some stuff labelled only "State Unitary Enterprise Hunting Cartridge" JHP ammo.

We're both untrained and inexperienced, however, so at 50 yards I was only able to hit one of those black targets that turn green when hit (forgot the name) 50% of the time with 70 rounds and my friend only hit it about 10 times with 70 rounds. Practice makes perfect, I suppose. It won't be long before I can add a Mosin-Nagant to my own collection and get better.