Hello all, I got a 350 legend barrel made by Deadshot Barrels. I didn’t notice when I first looked at it when I received it. While I was about to install it today I noticed they removed the bottom center lug when they machined the feed ramp. None of my other ar barrels is like this. Is it safe and/or will it effect accuracy? Being safe is my main concern.

Yes, due to the straight case of the .350 Legend there is a need to remove the bottom barrel lug for reliable feeding and to keep the lug from gouging the brass.

BS, we don’t have to remove that lug on QUALITY built .458 SOCOM and .450 BM so why does it need to be removed on the skinnier .350 L?  I didn’t need to remove that lug on my .338 GRRR done on the 6.8 case so why did they have to do it?  Answer, it’s easier to remove it and make a half-assed barrel work rather than take the time to make the barrel extension mods correctly.  Short answer is you don’t have to remove that center lug, not if the barrel maker has a clue on how to actually make a barrel and modify the BE.  

IMO return it and buy quality next time.  If you remove that lug, doing so redistributes back thrust forces so that the remaining lugs have increased pressures on them and instead of those forces being distributed equally in a circle around the bolt, the forces are now unevenly distributed.  Nothing good comes from that.

Ranier mods their extensions as well.

You're obviously not a fan of the Krag, I assume.

 
That’s what I was thinking. My 458 doesn’t have its lug removed either. I’m concerned that it isn’t safe on this 350 L. But I’m not a gunsmith or anything like that. So I was hoping to get some help. It seems there is mixed feelings.

Several people do that on their half-assed .458 S conversions too.  Doesn’t make it right or safe.

Last time I checked the Krag is not an AR, nor is an Enfield.

Well the mfg. just messaged me and said they have built many 350 L barrel like this with no issues.
I responded with: I don’t feel safe firing this barrel and will he replace it with a barrel with a better cut fed ramp or refund that barrel? I will see what is said.

I guess you don't consider Faxon quality.

Looking at how much bottom lug is left after cutting the ramp, it's not supporting much of the load in any case.  So, it's removal is not decreasing the strength . . .

Not seeing how removal of the fin on the ramped portion of the extension could be considered "dangerous ".

It's not like the case rim is unsupported once chambered.  


Eta OP's pic:

Attached File

What do you feel is unsafe?

My thinking is you are distributing the pressure on 7 lugs of the bolt, instead of all 8 lugs. So just quicker wear and tear or some kind of failure. I’m not a gunsmith and never seen this. So, that’s why I asked here and on other places. I’ve only had 3 say it’s fine. But at the time I message the barrel mfg. only 1 person said it was fine vs many saying it was not.

faxon 350 legends are the same way.

Not if they are removing the center bottom lug from their barrels.



Seems odd to me if TROMIX, Teppo Jutsu, SBR, Rock River, and SSK can make a modified barrel extension for their big bore cartridges, including the .458 SOCOM, .475 TREMOR, and .450 Bushmaster, and they don't have any feeding problems while leaving the center bottom lug in tact, then why does anyone think reinventing the wheel and removing most or all of the bottom center lug is a good idea.  Why remove it if you don't have to?  And most of you saying it is OK would scream bloody murder if your 5.56 showed up with the center bottom lug removed, or would you be OK with it if the maker told you they did that to make it feed better?  If the BE is done right, it will feed and eject 100% with the lug there, so you are OK with the maker, no matter who it is, half-assing it and grinding out the lug almost completely and in some cases, like many of the high quality Radical .458S we have seen, removing it completely?

The bottom center lug DOES NOT have to be removed to make it feed smoothly.  They only do that because it is quicker, and cheaper, to just grind out most or all the bottom lug rather than take the time to do it right and make two or three cuts to get the right angle.

Do what you want, it's your eyes and rifle.  If it breaks later on don't come crying that it was the ammo's or barrel's fault and ask for a new barrel. And just remember that the .350 L operates at a lot higher pressures than does the .458 SOCOM (36K psi), L operating at a full 55,000 psi (SAAMI).  Yes indeed, great idea to remove the bottom lug when the .223 is not deemed safe to use if one of its lugs breaks off at the same 55K psi.  What's the difference between one lug breaking off and removing one lug to start with (rhetorical question)?
I guess the next time someone's .223 or 5.56 breaks off a lug on their bolt or barrel extension we should tell them to keep on shooting, it's not needed.

Would be interesting if someone could post a photo of a "correctly modified" BE for comparison.

Tromix Big Bore Barrel Extension
"Feed ramp machined for wide body casings."

Attached File

Easy man, you sound as if you are near stroking out.


Some of us do not know big bore AR ins/outs and 350 L is relatively new.

Although the 350 is rated at the same max pressure as .223, recoil is said to be reduced because of the large case capacity and larger bore. This leads me to think that impact on the bolt and locking lugs is likewise reduced from .223/5.56 which probably explains the removal of the center lug, favoring more reliable loading over a lug that is really not mandatory for this cartridge.

The barrel mfg got back with me today. Told me even though they have made hundreds of these barrels with no issues. To send it back for a refund. My thinking this is not a 556 round and probably will take several years to have 5000 rounds put thru it. And the 350 L is relatively new to ar’s. How does he know there won’t be any issues. So I mailed it back to them. I’ll be ordering a barrel from x-caliber. The normal barrel maker and who I should have ordered it from to begin with.

Thanks all for your input!

lol he knew when to cut and run. I would have tried to break it.

Here is one from a TROMIX barrel extension, the older style.  New style is a bit different but still has the full bottom center lug.
Attached File


What you cannot see very well is there are two different angled cuts on the left and right sides of the M4 feed ramps and a shallow cut on the bottom center lug.  That lug is reduced very little but still allows for perfect feeding and full lug contact between the barrel extension and bolt.

Recoil has nothing to do with bolt lug and BE lug strength.  By the time the rifle starts its rearward recoil, the part you feel, the bullet is out of the barrel and pressures have dropped to almost nothing.  The highest pressure is when the bullet has traveled a few inches down the barrel, after that pressures are starting to fall way off.  By the time the bullet leaves the barrel, muzzle pressure is very low, only between 4K and 8K psi depending on load and barrel length.  By the time the bullet passes the gas port, pressures are down in the 10-15K psi with most loads.  It's those first few inches of bullet travel where if anything lets go things get real exciting rather quickly.

Thanks for the pics. Makes things a lot clearer.

The center bottom lug is not supporting anything, except your belief it needs to be there.

With a maximum bolt thrust in the 6 to 7 thousand pound range you're seeing about 1000 pounds per lug, do you really thing that thin piece of metal can support half a ton?.  That little nub isn't doing anything, and the load is distributed among the remaining six lugs.  

By the way, Armalite (new, not the division of Fairchild Aviation) has been making six lug bolts since the beginning.  The lug opposite the extractor has the rear face lowered about 0.010" so it doesn't make contact with the extension lug.

Euro ARs have a lug removed by law as they aren’t allowed mil spec items.  It makes no difference.

Interesting. Thanks for the factual info.

People have a remarkable ability to convince themselves of almost anything.  Just keep telling yourself whatever it takes to get you through the night.   No skin off my nose.

You seem awfully invested in this personally.

Do you have any data that suggests otherwise?

The Norwegian Krag.    Better in lug design and cartridge.   Uglier though.  That said I have a 1901 US Krag and like the .30-40 cartridge.