Ok, I bought a fn 49 from another cgn after it blew up on him. Repaired the damage & am waiting for a firing pin. I have not seen any obvious cause for the blow up. As I was checking the action with some reloads & bolt was somewhat hard to close on the round. New pmc case, same thing, egyptian surplus, bolt closes fine. On the pmc & the reloads there was a contact ring mark on the brass where it hit the front of the chamber, on surplus, no ring. Ever heard of this before? I thought military chambers were supossed to be loose in case of dirty ammo.Maybe a contributing factor in the blow up?
Need help with fn49
- Thread starter desporterizer
- Start date
My understanding was that the military chamber internal diameter was loose, not OAL. OAL can't be loose, as if it is, the firing pin migh not reach the primer. What's the origin of your gun? Is it Egiptian?
Then I (with my tiny bit of experience with the guns, correct me if I am wrong!) would suggest that the manufacturer of Egiptian ammo knew of the issue/defect of the receivers and adjusted the rotary brass presses as to the height. Must be a feature of all Egiptian rifles than. If it is not, than I dunno 
Think it's just a tight chamber, but could be wrong. Definitely sounds like not enough freebore at front of chamber. Not a huge problem to corect. If you don't want to ream the front of the chamber, trim your brass (cheapest way).
Problem with these is that the gas is so #@*&% hard to adjust..... mine would "double", second round a slam-fire, until I realized that the problem was the mild loads and slow powder I was using. Adjusted the gas, okay. Went to factory ammo, had to adjust gas back for quick powder. It's quicker with the FAL, but the same basic system: constant gas takeoff at port, bleed the excess out the bleedhole.
But it's a stinker having to take the wood off to do it.
Problem with these is that the gas is so #@*&% hard to adjust..... mine would "double", second round a slam-fire, until I realized that the problem was the mild loads and slow powder I was using. Adjusted the gas, okay. Went to factory ammo, had to adjust gas back for quick powder. It's quicker with the FAL, but the same basic system: constant gas takeoff at port, bleed the excess out the bleedhole.
But it's a stinker having to take the wood off to do it.
I don't think trimming would help, the contact ring is right at the transition near the case wall. Just seems like civi cases have the shoulder a little further forward than milsurp brass. Resizing has no effect, the die doesnt push the shoulder back enough. I tried a milsurp case in the die & it didn't even touch the shoulder. I think thats why it blew up, the previous owner let the bolt cover handle go too gently & the cover didn't lock the bolt( its hard to see when you sight down the rifle), pullled the trigger & boom! With the bolt unlocked the rear of the case blew off, shoved the bolt back & damaged some parts. Never seen an unmessed with mislup have too tight headspace before.
Never mind. I found the problem, RUST! There was a ring of either rust or crud from the forward part of the chamber not being cleaned. A little steelwool on a bore brush & factory ammo chambers normally. I had to look into the chamber with a bright penlight to see it. I think I will be checking all my milsurps chambers a little more closely now.
