.50 bmg barrel length, velocity, anti-material effects on target

AbominableSnowman

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I've scoured the net and can't find what I'm wondering about. I'm looking into ordering a Serbu RN-50 single shot.

This will be for fun. Simply to make me laugh and smile. I want to wreck things. Old cars, washing machines, whatever.

I might want to get into long range shooting eventually, but that's not my intended purpose for the entry level fun gun. I have no ranges available beyond 600 yards or so and won't for the next couple years.

I have to choose between the 29 inch barrel or 22 inch. I like the idea of the 22 for easier packing, carrying through the woods to the ranges without banging the muzzle or catching a branch, etc. Basically more portable and lighter weight.

I'm aware there will be more felt blast, and that long range might be more difficult so please let's not address that right now.

With 5.56 I know that at roughly 3000fps it will punch through things much better than from shorter barrels.

My question is, does the loss of velocity from 2800ish to 2500ish greatly reduce the penetrating ability of the .50? Or does the mass of the projectile make up the difference in comparison to 556's abilities to penetrate armor, engine blocks, etc?

Thanks in advance.
 

Sixfivesavage

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Just to stir the pot here.....you're asking for more "kinetic".....this brings back memories for some of us.
 
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Ledzep

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Faster is going to penetrate more.

For what you're talking about (cars, washing machines, etc.) it probably doesn't matter, but I would get the 29" in the event you ever wanted to stretch it's legs and to get the blast away from you. I had a 24" BMG for a while and the blast got obnoxious. I ended up selling it after the initial fun wore off.
 
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AbominableSnowman

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Just to stir the pot here.....you're asking for more "kinetic".....this brings back memories for some of us.
I don't follow. I'm aware that more velocity brings more kinetic energy. I'm just curious if the velocity loss from the shorter barrel makes a significant difference in destructive power, or if it won't make much difference because 556 vs 50 comparisons are apples to oranges. Maybe 3000ish fps is a magic number for penetration, or maybe the projo size makes up for it. I don't know.

I had been ok with the idea of some extra blast if it's much more portable, but you all know more than me about this so I'm taking that into consideration now.
 

Sixfivesavage

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I don't follow. I'm aware that more velocity brings more kinetic energy. I'm just curious if the velocity loss from the shorter barrel makes a significant difference in destructive power, or if it won't make much difference because 556 vs 50 comparisons are apples to oranges. Maybe 3000ish fps is a magic number for penetration, or maybe the projo size makes up for it. I don't know.

I had been ok with the idea of some extra blast if it's much more portable, but you all know more than me about this so I'm taking that into consideration now.
Just an inside joke from long ago now. No big deal. I haven't played with a 50 much but I would imagine someone in the ELR game would know some powder burn numbers, maybe from quickload. I would just go whatever length would get you a complete powder burn. What that length is, I do not know.
 

KYAggie

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Have you ever shot a 50 bmg? If so what was the barrel length? I’ve shot about 30 rounds through a 29” bmg and there’s no way I would mess with a 22” barreled one unless my life immediately depended on it. The pressure wave even off a 29” barrel is significant in my opinion and will likely take a little getting use to.
 
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AbominableSnowman

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Have you ever shot a 50 bmg? If so what was the barrel length? I’ve shot about 30 rounds through a 29” bmg and there’s no way I would mess with a 22” barreled one unless my life immediately depended on it. The pressure wave even off a 29” barrel is significant in my opinion and will likely take a little getting use to.
I have not but as much as it is mentioned it must really be significant.

Flipping the question a little.. If I eventually add a suppressor, a 29" would be way too long for my tastes..

With a suppressed 22" would I lose significant penetration potential?
 

W54/XM-388

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I have not but as much as it is mentioned it must really be significant.

Flipping the question a little.. If I eventually add a suppressor, a 29" would be way too long for my tastes..

With a suppressed 22" would I lose significant penetration potential?
If you want suppressed, get a long barrel and make sure to get a suppressor that has a brake at the end of it to help a bit.

Shooting a suppressed .50 without a brake, in bolt, such as the AI 50, is kind of like getting kicked in the face by a mule every time you pull the trigger.
 

AbominableSnowman

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Looks like either way I will want the longer barrel. Especially considering the full performance. I'll have to haul it around in a case with upper and lower separated.

Thanks all
 

chevy_man

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Looks like either way I will want the longer barrel. Especially considering the full performance. I'll have to haul it around in a case with upper and lower separated.

Thanks all
No, you just go to the gym! Otherwise known as long walks with your rifle.

There are only 1-2 suppressors for a .50 and they'll last longer on the longer barrels.


Handy is for normal rifles. You sacrifice everything normal when you want a .50.
 
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TxWelder35

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Another plus of a longer barrel is more weight. More weight is less felt recoil. I’d want that rifle as heavy as I could get it.
 
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Dolomite_Supafly

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With a 24" barrel I am getting an average of 2,580 using Lake City API.

My gun weighs 21 pounds ready to go. It was a LOT heavier so I machined a lot of weight off the barrel to make it lighter. With an Armalite brake the recoil is less than a standard 308 hunting rifle.
72396560_796345447465943_7507691528777629696_n.jpg72868984_580490395824138_4607626342324764672_n.jpg
 

KYAggie

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The recoil can be managed with a good break and weight; it’s the pressure wave that becomes obnoxious. Exponentially obnoxious the shorter the barrel. As others have indicated, the 50 bmg is not a walk around gun, it’s more like a crew served weapon.
 

hollowoutadime

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I have a few fifties. Recoil can be pretty brutal, to where it feels like getting whacked while you have a head cold. An M82a1, while likely less acccurate than an M95, or Robar bolt, it still nowhere as enjoyable as a suppressed 338lm. Cans and scopes that can handle the energy are also expensive. That said, if you have the coin, add one to the stable. My kids always enjoy a few rounds when I bring em out.
Barrett0208151453.jpg
 

DJL2

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Bro, what you need is an NTW-20. Forget .50 Cal...you want the 14.5x114mm variant. More energy at 1000m than the .50 BMG at the muzzle. If you want something "small," go find a .408 or .375 CheyTac.

OK, seriously, penetration is going to depend on two factors:
1. Energy available. Energy is, from an engineer perspective, the ability to do work (creating shear failure in materials, generally, in this case)
2. Ability to transfer that energy (i.e. capable of applying an impulse load across a small area to induce failure)

To the first point, yeah, you're giving up performance (but you already knew that). To the second, for optimum performance, pick the right sort of projectile. How much performance do you need for just having fun? For funsies, I wouldn't prioritize the carrying over the shooting.

If you're worried about what that means in real terms, look up the down range performance of the M2 family of weapons and ammunition until you arrive at a velocity range that corresponds to that which you are considering. It'll set you at ease.

I ran the 750 grain A-Max at 2500 fps through JBM for you, just to ballpark things. @600 yards, it still carries 2000+ fps for roughly 6800 lb-ft of energy. In perspective, that's more energy than a 225 grain .30 cal bullet @ 2850fps has at the muzzle...by more than 50%. You can find something you won't be able to break with that level of performance...but, you're gonna have to work at it a little.
 

Dolomite_Supafly

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As others have indicated, the 50 bmg is not a walk around gun, it’s more like a crew served weapon.
Depends on the weight. 21 pounds is heavy but I know quite a few people with heavier guns shooting smaller calibers. My 6 BR will be over 19 pounds when everything bolted on.

Would I want to carry a 21 pound gun through the woods to hunt deer, probably not. Could I, absolutely. And considering the energy per pound it is hard to beat a 50 at almost any weigh

My goal was to have a sub 20 pound 50 BMG. It is 21 pounds now but the next time I have it apart I will meet that goal. I am thinking I could probably get below 19 pounds. A quality muzzle brake does more to reduce recoil than weight. Like I said mine has less recoil than a 308. The blast can be rough but that can be mitigated as well.
 

Dolomite_Supafly

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As others have indicated, the 50 bmg is not a walk around gun, it’s more like a crew served weapon.
Depends on the weight. 21 pounds is heavy but I know quite a few people with heavier guns shooting smaller calibers. My 6 BR will be over 19 pounds when everything bolted on.

Would I want to carry a 21 pound gun through the woods to hunt deer, probably not. Could I, absolutely. And considering the energy per pound it is hard to beat a 50 at almost any weigh

My goal was to have a sub 20 pound 50 BMG. It is 21 pounds now but the next time I have it apart I will meet that goal. I am thinking I could probably get below 19 pounds. A quality muzzle brake does more to reduce recoil than weight. Like I said mine has less recoil than a 308. The blast can be rough but that can be mitigated as well.
 

Reverie Ranges

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Good Lord! Why the .50 so bad? They are fun to shoot but the funding for one is a bear... DJL2 is certainly correct about better cal rifles out there. I did scope testing for the XM107 on a bolt .50 cal. Brutal after several days of shooting cases of ammo between the lot of us. If you want to just blow Sh*t up, join the service and get an EOD job.
 

Dolomite_Supafly

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Shoot through a barricade. I am probably going to build a sort of blast shield almost like WWII artillery pieces just a lot smaller.