most of those have been declared unsafe ro use for any length of time. if you want to fire 40-50 rounds in your life they're probably fine. if you want ot fire 40-50 rounds every month they can kill you. there is a thread going on over on arfcom right now where one of these conversion guns permanantly crippled a man. ill link it if i can find it again.
I did a little research to see what I could turn up. appearantly you beetr off savaing and buying a complete rifle. Seem that out-of-battery discharges are very common on these conversions. and, there is enough energy in this round that it is launching the bolt completely through the man behind the trigger. there are countless reports of bolt lugs shearing off, recievers exploding, barrels blowing off, and not to mention the HUGE amount of maintenance involve with one. I think I'll just save up and by a barrett.
A friend of mine has the BOHICA .50 upper, which is single shot only. Not sure how that one is on safety, but he seems to be a very intelligent fellow who researches things so it's probably safer than this. Personally, I would just go for a BFG-50 from Serbu though, which is built specifically for .50. http://serbu.com/top/bfg50.php
the uppers that have to date had out of battery fires, or catastrophic failures of the bolt and or breech (causing severe injury in ALL cases) BOHICA, Cobb, ALS (primarily these fail. one nearly killed a man at the 09 FCSA championship). these have been declared UNSAFE TO FIRE by the FCSA and are forbidden at thier events. if you own one it is seriously suggested you either cease us eof it or only use downloaded ammo until the safety problems are addressed. ALS uppers reccomend you do not use them AT ALL until the safety issue is resolved (and as ALS is no longer answering phones, returning e mails or having any contact at all with the public, one can assume they may have bailed on the whole situation and are hiding behind lawyers).
the single shot .50's are going down in price... a grizzly is around 1500 and i'm sure there are more around that price range, i really don't want one, but it would be on my fantasy list. just don't see a need as a civilian, unless bragging rights.
Post a link to a thread showing pictures or even a first hand account of a Bohica having an issue and I'll agree. I own one and the receiver design and bolt design basically make it impossible for an OOBD. Bolt lug failures could be possible, the earliest models of the Bohica Mark I had soft bolts, but not a single actual failure, just growing headspace, but these were all caught early on. The remaining models II-IV haven't had the issues.
I've read the same reports about the ALS design, but it differs dramatically from many of the other single shot builds.
If a 308 or 30/06 cant handle it I doubt a 50BMG would either unless you have a tap into ammo that I haven't been able to find. AP Explosive would be effective against light armor but I haven't seen any in a long while. Of course that doesn't mean 50BMG isn't fun to shoot it is. Save your money and get something safe.
i saw the threads on arfcom in the 50 cal section but ive been banned from arfcom so i cant link to them. the BOHICA upper was specifically mention in a thread listing uppers that the FCSA had banned because there had been an issue with them at one of thier matches. however i couldnt not find anything on the FCSA web site abotu what equipment was banned or not banned. youd have to contact FCSA directly and ask them. all my info came from threads where users had had problems with said equipment. the BOHICA complaint was a catastrophic bolt failure IIRC. youll have ot hunt around over on arfcom to find the thread, it was a few pages back in the 50 cal section it could have been a mark I as you said that had bolt problems. there was pics in teh thread of the damaged exterior but no interior shots so youll have to take that with a grain of salt. they may have been cut and paste or photoshops for all i know.
not trying to bash any particular brand here, just dont want anyone to get hurt. seen firsthand waht a 50cal KB can do and i dont want ot be anywhere near another.
Negative on the Bohica ban at FCSA. There's nothing in the thread, only ALS has been pulled until they have a cause of the failure and a method to correct. Even if you've been banned you can still view threads.
There hasn't been a single bolt head failure on a Bohica that's been printed, firsthand or otherwise. A quick look at a Bohica upper shows that that even in the unbelievable event of a Kaboom, the receiver and bolt is well contained, much better than most.
And I want everyone to realize that Bohica's aren't made any worse than any other gun, and they aren't falling apart in 40-50 rounds.
As shown Bohica's were shot right along with other guns at the most recent event. They weren't pulled from the line like the ALS units were. There's nothing inherent less safe about a upper gun vs. a built gun, if everything is designed correctly in regards to fire control system. I'm still of the opinion that the ALS failure was partially shooter induced. The bolt design or something may not be sufficient to ensure that it doesn't happen, but something else was going on to cause this to occur.