Took a newer Bushmaster BA-50 out to range and had a 50-60% Failure to fire with NEW Lake City ball ammo. Odd thing is I pre-cleaned gun, and closing bolt handle was really tight  (bearing riding on rail towards the rear of gun)
(The bolt and carrier passed the test, per manual so I think it was correct)
Then after shooting 8 or 10 rounds,  the bolt handle was then VERY loose!
I can use my pinky & lightly tap up on the bolt handle and it just pops right up! Almost feels sloppy & this is a newer gun. Also I can move/jiggle the closed bolt carrier with my finger.

So naturally I start thinking of worse case scenarios and remember about 1 guy online who had a light strike which was a major issue with his gun it was the barrel working its way loose from the receiver.
Could this be the reason the bolt handle is so sloppy and loose after firing a dozen rounds?  Hopefully NOT.

Any other BA50 owners.. is your Bolt handle loose as I described? Can you tap it with your pinky and the bolt handle will flip up easily? can you reach in with a finger and rattle/jiggle the bolt carrier slightly when loaded or not? have you had any FTF issues? remedies? Any issues with new Lake City Ball ammo? (one Gunsmith said the LC with links is designed for machine gun and the primers are not for precision rifles)  Any chance an owner could post a picture of stock hammer, spring trigger so I could verify this one is stock and hammer spring  installed correctly?
It appears intact and not broken at least. I dry fired, tested the release of the hammer and it seems to strike hard  (a little scrape on top of hammer? but no evidence of it coming in contact with top the bolt carrier at all)
I am considering to send to Bushmaster.. bvut hoping I could answer a couple basic questions here from other owners?  
Thanks for any assistance

I can't offer you any help, but if you have doubts on the safety of this firearm, do not fire it.  Find a qualified gunsmith who can go through the rifle to determine what may be wrong.  It's better to be safe than sorry.

Good Luck!

So I met up with another guy on forum & fellow BA50 owner & was able to compare the action. His has about 20 rounds through.. he has not had any FTF's using American Eagle.
Our rifle has 70-90 rounds through with 50-60% FTF rate with New Lake City Brass (Are these rounds actually from same factory? same round basically?  

Test comparison results: His bolt carrier would also rattle/jiggle with bolt down, empty chamber using finger.
His Bolt action would also slightly jiggle when  bolt closed with round in chamber.

His bolt was also VERY easy going up.. (mine might be a slim amount easier.. which could account that I have 4 times as many rounds fired?)  These bolts move like butter!

We had the same amount of thread showing were the Barrels are torqued on to action.

We both agreed the hammer pull tension was very close or the same.

So the action was very similar if not mostly the same. So the question still stands; what is causing mine to 50-60% FTF's ?
Could it be the bolt carrier was not completely assembled correctly before? could the Firing pin be catching slightly? I know the firing pin spring was difficult get out.. had to soak some solvent over night and it came out on my pre-cleaning. and post range it was still took a hook tool to get the spring to come out but it did come out sooner with oil this time.. (I cleaned the spring pin cylendar after with a .223 cal brush)
So should I take it in or try a different batch of ammo.. maybe PCM or American Eagle?  
Does any body have any other suggestions?
Or could it still be a head space issue? (even with the bolt action similarities with another BA50 ?)

I feel a little safer seeing the similarities with the other rifle? , so maybe I am NOT quite as worried as I was before, that the Barrel is coming loose, which was reported by one guy in New York State couple years ago? (who has not followed up on his post)
Or should I NOT test it anymore and send it in to Bushmaster for fix/adjustment?

Thanks again for any suggestions from anyone with past or present experience with the BA50 or Cobb 50

We had some SUCCESS with the FTF issue!

Removing the firing pin spring was kind of difficult, the spring would NOT just fall out when removing the firing pin. I put some cleaner inside spring/pin chamber let it soak, I had to use a tool to try to wedge it out. Now, if I press down on spring with an allen wrench, then slide wrench off (as spring is depressed) & that "pops" the spring out.
I also cleaned out the Firing pin spring chamber with a .25 cal bore brush, cleaned & oiled the Bolt action again.

So went to range and only had 1 FTF (2nd round which fired on 2nd pull) out of 18 rounds! (rifle just passed break in, is at 80-100 rounds approx)
We have heard of Bushmaster making adjustments if you send the gun in to adjust head space issues, FTFs.. & improving accuracy. It appears for the time being we will not send this one in.  

So far have eliminated several issues;
1. FTF's
2.adjusted extractor spring.
3. stretched out magazine spring which fixed a Magazine feeding issue

Still have issues with getting to Zero, with a 8-12" & + spacing  (@200 yards).
(test shooter uses prescription glasses) and 1st time fine tuning of a Nighforce Benchrest scope (12-42x56) Yet to determine if it is improper adjustments, shooter error, parrallax, mirage, scope mount (Larue LT111) or scope itself?  
Am going to get a rear monopod and see if that can help alleviate or reduce any shooter errors.. and also choosing a range in Western WA (within 1 - 2 hour drive) to shoot more often.

To OP-

How do you like the trigger?Hows the bipod?does it cant without much force apply?Did you get the accuracy back ?I am about to pull a trigger on BA50 but I would like to gather more info If I can.

Trigger is OK for me, some have put a different hammer spring.. I had 2 failure to Fires out of 28 Rounds last time out.
You can get a new trigger $59 here?  http://www.triggerwork.net/bushmaster-ba-50.html
Anyone try?
I am a novice with this Cal. Still getting scope squared away (I may have a problem with 1st one.. Nightforce, so I sent it in)  going to try a larue 50 Cal mount..
The backup Super Sniper 10x is OK.. but I wish I went with the 12X power.. I just got some bright red 2" target stickers.. as the Targets I were using were for pistol range with a 8" black target That I wanted to use up.. but at 200 yards definitely not what I should have been using..  which may be some of the issue with accuracy?
I am using Burris tactical rings with the S.S.  scope
I Need to square up & try again this weekend as I am still  5" groups at 200 yards..
I should get the Night force scope back in a couple weeks.. and give that another try. Hopefully I can get zeroed shortly after that.
If not.. then I would have to consider sending rifle into Dakota Arms via Bushmaster have them check head clearance.. make adjustments.
I read one person who had very good accuracy after sending his in.  
The Mag works OK.. A little sticky.. shoving them through.. but works.
Rifle is probably at 175-200 rounds through.
Bipod? Well I turn it around backwards, use a washer,  and then install nut and it will tighten up firm.. If you put it on the factory method the rifle will sway from side to side.
I might consider a future upgrade on the bi-pod.. once I get zeroed I will re comment on how much of an issue that movement is. .

New Firing pin from Bushmaster..original one did not have enough protrusion. My head space was checked with no issues, no barrel problems. they also polished chamber and new extractor..
Very Good customer service on this.  
Switching to American eagle in the black box and will also try some Hornidy on occasion if instead of Lake City Brass next time out.

My local store has one for $3600.  I havent seen one that cheap before.  What is a good sale price?

Does anyone know if Cobb has a active number? I looked on the website and tried to call them but got the inactive number message ? I’m looking for a firing pin and a few other parts. If anyone knows or has extra parts please help. Also, will a complete BCG from Bushmaster 50 BMG fit and function in a Cobb 50bmg? Exploring some options since I have light primer strikes too.

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Nice to see this.