Is there a safe 50bmg AR Upper..?

[ke6guj]

Is it true that there is NO SAAMI SPEC for the 50BMG?

What standard is the (typical) standard by which to base one's handloading - other than factory load data?




Cheers
Tinker

yes, it is true that there is no SAAMI spec for the .50BMG. Because of that, each manufacturer's chamber may vary from other brands.

The .510 DTC EUROP does have a standardized chamber, spec'ed through CTP? of europe. But that is pretty much useless since a batch of reamers were made in the USA with improper shape due to a misread/typo of the spec.

EDM chambered a small batch of guns with that "wrong" reamer, and when the error came up, instead of fixing the guns, they decidedto call the "wrong" spec the .50DTC-EDM . So now there are two versions of the DTC, one which is standardized and one that is a wildcat version of it.

[ke6guj]

Thanks for your comments

I'm just looking for published factory load data, not your specific loads.
The distinction of 'starting loads' came up around your comments, which has me wondering what we could use for comparison.
I don't run these cartridges - for the most part the BMG is much too new for my tastes!

wow, you must really play with the old stuff. A 90-year-old cartride is much too new for you? I guess if you are playing around with pinfire cartridges, then a 90-year old cartridge could be considered a newcomer

On the link in my signature line, I HOPE THAT'S NOT A VIRUS!
I'll explain -- this website has a notoriously crappy search feature.
Many members of the calguns community have commented on it - and one particularly creative member actually fired up a google-based Calguns specific search utility.
Clicking on that link gives you the search page, ready to go.
I quickly got tired of trying to find where it was posted here on the site (by way of using the Calguns website search...) so I just pasted it into my signature line so I can always find it.

Give it a shot.
It works great.







Cheers
Tinker

There is a link to Oaklander's CGN google search on every page. It is in the top blue bar labeled "CGN Google Search".

[a.tinkerer]

Golf Uniform Juliet-



Thanks for the notes there.
What a mess.

yes, it is true that there is no SAAMI spec for the .50BMG. Because of that, each manufacturer's chamber may vary from other brands.

The .510 DTC EUROP does have a standardized chamber, spec'ed through CTP? of europe. But that is pretty much useless since a batch of reamers were made in the USA with improper shape due to a misread/typo of the spec.

EDM chambered a small batch of guns with that "wrong" reamer, and when the error came up, instead of fixing the guns, they decidedto call the "wrong" spec the .50DTC-EDM . So now there are two versions of the DTC, one which is standardized and one that is a wildcat version of it.

On the pinfire comment - yes I do play with pinfire rifles.
I have some very very nice best grade sporting double rifles from the early-mid 60's
I like them very much!
Cool thing about them, is that you see how your firing pin protrusion is EVERY TIME YOU CHAMBER A COUPLE OF ROUNDS!
Sweet rifles.



And --- thanks for the note on the search link!
Me-Duh!

Cheers
Tinker

[CSACANNONEER]

First and foremost, I refrain from posting any load data of any sort. What works in my rifles may not in yours.

As to the revisions, I think they are more quality improvements rather than safety improvements. I have shot them all through the MkII with some MkIII upgrades. Receiver material changes, Chrome bolts, and bodies, Improved bolt handles, improved bi-pods, improved muzzle brakes, improved chamberings. Free float handguards, improved optics rails and Good customer relations considering he is a small operation.

What is that google link in your signature line? My PC identified it as a Virus.

Good idea about not posting load data right now. Too many beginners might end up doing something unsafe because they don't understand the big50 yet.
The problem with you stating that you don't go over 215gr is that you leave way to much info out. We don't know what type of powder, lot number can me the difference of over ten grains with some 50 powders!, the style and weight of the bullets you are loading etc.

Regarding the design of BOHICAs, I've always had my opinions and ,as some here have recently posted, there do seem to be some problems with them being able to fire before the bolt is 100% closed. This would be EXTREMELY UNSAFE and I suggest that no one shoots any rifle of any caliber which can fire this way. However, if you look at the pictures, you will see that the lugs appear not to be damaged. This could indicate that something else happened. In the case in question, it might not have been a design flaw. The OBD could have been caused by anything. We won't know until/unless an independent and neutral 3rd party gets a chance to investigate it. Even then, we may never know.

On the pinfire comment - yes I do play with pinfire rifles.

Tinker

That sound really cool. I have zero experience with pinfires but, they do intrigue me a little.

[supersonic]

However, if you look at the pictures, you will see that the lugs appear not to be damaged. This could indicate that something else .

Greg-
Yeah, I noticed that too. It looks as if the bolt head (of course with a new FP & extractor) could be put right back in the gun and fired with no problem. However, the reality is that that precision-machined piece just took on a megaton impact and would (for safety reasons) need to be MagnaFluxed plus HP tested and certified by a qualified metallurgist before I'd use it again!

[a.tinkerer]

Cannoneer-


Handloading is special work and load development should always be approached with caution.
Got it - I totally agree, and I think that this should be trumpeted from the highest hills of calguns on a daily basis.

Furthermore, with the (I'm learning more about this by the hour) totally UN-STANDARD nature of hobbyist BMG(and whatever other suffix surrogates) accessory conversion kits, that could only further complicate things.
Still my sense is that y'all in the 'shooting (these) conversion kits club' are starting with SOME sort of load data.
Y'know, stuff like one finds on the Hodgdon website...

Good idea about not posting load data right now. Too many beginners might end up doing something unsafe because they don't understand the big50 yet.
The problem with you stating that you don't go over 215gr is that you leave way to much info out. We don't know what type of powder, lot number can me the difference of over ten grains with some 50 powders!, the style and weight of the bullets you are loading etc.

Regarding the design of BOHICAs, I've always had my opinions and ,as some here have recently posted, there do seem to be some problems with them being able to fire before the bolt is 100% closed. This would be EXTREMELY UNSAFE and I suggest that no one shoots any rifle of any caliber which can fire this way. However, if you look at the pictures, you will see that the lugs appear not to be damaged. This could indicate that something else happened. In the case in question, it might not have been a design flaw. The OBD could have been caused by anything. We won't know until/unless an independent and neutral 3rd party gets a chance to investigate it. Even then, we may never know.




That sound really cool. I have zero experience with pinfires but, they do intrigue me a little.

On the orig question of this thread - is there a safe unit, so far the only one that this thread has spoken to have truly redundant safety features is the ferret (with it's firing pin block) - the hammer block of some of the kits is at least something.
I wonder if there are others with firing pin block features.
The Ferret appears (by way of reputation) to be pretty accurate too!



On the pinfire rifles - they're total time machines.
I'm very enthusiastic on the period of development of the metallic cartridge, especially around the highest quality sporting rifles.
That's where the highest art and development were happening - in/on the hunting rifles of the royalty and aristocracy.
Cool stuff.
Look here for the story on a really neat one with significantly interesting provenance.





Cheers
Tinker

[a.tinkerer]

Supersonic-

Greg-
Yeah, I noticed that too. It looks as if the bolt head (of course with a new FP & extractor) could be put right back in the gun and fired with no problem. However, the reality is that that precision-machined piece just took on a megaton impact and would (for safety reasons) need to be MagnaFluxed plus HP tested and certified by a qualified metallurgist before I'd use it again!

I've had nondestructive metal testing done to quite a few of my rifles, not necessarily because they'd been blown to bits, but because they're ~150yrs old.
As you likely know, it doesn't really even cost much to have parts tested and X-rayed.

What a memento, 'the bolt head that survived a wreck that killed the rest of the rifle...'




Cheers
Tinker

[CSACANNONEER]

Tinker, to answer your original question, the answer is "NO". There is no AR upper or other firearm in any caliber which is 100% safe, no matter what. Sometimes SCAT just happens. The only two uppers which I like to recommend are the ALS and the Ferret. I know both manufactures and both guns shoot as well or almost as well as amy other benchrest rifle out there. Yes, I put both of them in the same category as bench rest guns because, that is one purpose they were designed for. I choose to get an ALS because, I think it is capable of shooting slightly more precise than a Ferret but, I'd be very happy with a Ferret in my small 50 collection.


So, how do pinfire rifle cartridges differ from pinfire handgun cartridges? Or, do they? Do you reload your own rounds?

[rbthntr64]

My guess would be that the upper is fine other than the bolt assembly. I would have the back of the upper x-rayed to make sure there is no stress fractures from the impact that made that mark.
CSA, I respect your opinions and agree, until a qualified expert analyses the rifle, we will never really know what happened.
I have my opinion of what an expert is, and it isn't a sunday shooter that shoots a 50 BMG rifle at their local range or Raton for that matter. It would have to be Dan Lilja, Ronnie Barrett or the likes of Rock Mcmillan. These guys are experts, someone who shoots 50 BMG for sport is not, including myself, and I have build my own rifle.

[a.tinkerer]

Cannoneer-



When I was a teenager I worked in a bicycle shop as a wrench.
One day a lady and her daughter came in shopping for a bike to send off to college with the girl.
Mom asked which bike was the safest - to which I answered something to the effect -- '...there's nothing safe about bicycling...'

Freaked the gal out, but ended up making the point and carried on to sell them a bike and some gear (helmet/gloves/lock/etc)

From that perspective, the current fad of one-speed velodrome-style street bicycles with fixed gearing (no freewheel) and NO BRAKES are not safe.
Bicycles with brakes and forgiving frame geometry and seating positions are safe(r)

Tinker, to answer your original question, the answer is "NO". There is no AR upper or other firearm in any caliber which is 100% safe, no matter what. Sometimes SCAT just happens. The only two uppers which I like to recommend are the ALS and the Ferret. I know both manufactures and both guns shoot as well or almost as well as amy other benchrest rifle out there. Yes, I put both of them in the same category as bench rest guns because, that is one purpose they were designed for. I choose to get an ALS because, I think it is capable of shooting slightly more precise than a Ferret but, I'd be very happy with a Ferret in my small 50 collection.


So, how do pinfire rifle cartridges differ from pinfire handgun cartridges? Or, do they? Do you reload your own rounds?

Back to the pinfire thing -- pinfire rifles are much like the unsafe bicycle I mentioned above -- and that's one good reason that they're obsolete!

From the period - the rifle cartridge cases had thicker case heads, they had rims, they had base-wads, nearly all of them had paper case-walls, the bullets of the pistol ammunition were typically heeled like .22lr bullets are, rifle bullets typically weren't -- also the rifle cartridges packed a much bigger punch!


Take a look at the linked thread.
There's a bit of history on the cartridge type, also some discussion on how I made cases for that rifle.
The first two cases were turned from titanium barstock.
The bulk of the ones I have for that particular rifle are swaged from modern thin walled brass cases.


Also that rifle -- very special.
There's more going on in the triggerplate of that little rifle than there is in the whole bohica kit!






What's your take on the Serbu 50cal conversion kit?



Cheers
Tinker

[50 Shooter]

Mark Serbu doesn't make a 50 BMG upper for an AR lower, he makes standard rifles. He also has a semi auto 50 BMG about to hit the streets.

[ke6guj]

What's your take on the Serbu 50cal conversion kit?



Cheers
Tinker

Serbu doesn't make a "conversion kit". They sell a complete .50BMG rifle. AFAIK, Serbu did help design a BMG upper for AR-pattern rifles for one or more parties, but Serbu doesn't sell them themselves.

[1919_4_ME]

Mark Serbu doesn't make a 50 BMG upper for an AR lower, he makes standard rifles. He also has a semi auto 50 BMG about to hit the streets.

It will be out "2 weeks"....

[CSACANNONEER]

I have my opinion of what an expert is, and it isn't a sunday shooter that shoots a 50 BMG rifle at their local range or Raton for that matter. It would have to be Dan Lilja, Ronnie Barrett or the likes of Rock Mcmillan. These guys are experts, someone who shoots 50 BMG for sport is not, including myself, and I have build my own rifle.

While I agree that a sunday shooter is not the best choice. I think that there are some people as qualified or more qualified than the folks you mentioned. But, if you can get any one of them to head up the investigation, let me know and, I'll pass it on to the people who need the information. Who knows?
If you can't ask them, I just might ask them next week. I'm sure I'll see all three either Monday or Tuesday.

[a.tinkerer]

Anyone here know the particulars of the UltraMag fire control/safety features?

Of this type of conversion kit, the UltraMag definitely 'looks the coolest'




Cheers
Tinker