LMT Specific Ammo Question

kingdarb

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Heya folks. I am waiting for my first AR (a 16" LMT) that I recently bought. Sooo I need ammo. It's a little hard to track down 5.56....

Have any of you folks with LMT's shot 55 grain 223 out of it? If so, did you have any problems? Did it cycle the action properly? I doubt it could hurt the gun which is made for 5.56 pressures....

I was figuring that I could get some 55 grain 223 and reload the cases after being fired once with a heavier bullet to better suit the barrel twist.

Thanks in advance!
 
No issue with 223 in my LMT Defender 2000. .223 in 5.56 chamber is a go. No go the other way around due to the higher pressure of 5.56 ammo.

Cool thanks. Yeah, I read that 5.56 is a no-go in 223 chambers and that 223 is fine in 5.56, just wanted to make sure that the action will cycle ok in it.

Confusing the whole issue is that the chamber is specced 5.56 but stamped 223 lol. :)

Thanks!
 
That's just to get around US export regulations (ITAR).

At least with a quality rifle like LMT, you actually have a 5.56 chamber. Some "just as good as" makes that actually say 5.56, do not have 5.56 chambers. This is changing a bit now, due to their fear of being sued when someone tries to use 5.56 in their "5.56" rifle.

At worst, you may have to change the buffer from the H to the C(arbine) if you use some of the weaker stuff, especially in cold weather. Stick with standard "mil-spec" springs, you won't need any "coloured" springs to run pretty much any ammo through your LMT.

You'll know if this is necessary if the rifle starts short stroking and you have FTFs. It doesn't hurt to carry a selection of buffers (C, H, H2, even H3) once you get into ARs more. Especially if you shoot with people who have "just as good as" rifles, and you can get their gun running better for them.

Regards.

Mark
 
That's just to get around US export regulations (ITAR).

At least with a quality rifle like LMT, you actually have a 5.56 chamber. Some "just as good as" makes that actually say 5.56, do not have 5.56 chambers. This is changing a bit now, due to their fear of being sued when someone tries to use 5.56 in their "5.56" rifle.

At worst, you may have to change the buffer from the H to the C(arbine) if you use some of the weaker stuff, especially in cold weather. Stick with standard "mil-spec" springs, you won't need any "coloured" springs to run pretty much any ammo through your LMT.

You'll know if this is necessary if the rifle starts short stroking and you have FTFs. It doesn't hurt to carry a selection of buffers (C, H, H2, even H3) once you get into ARs more. Especially if you shoot with people who have "just as good as" rifles, and you can get their gun running better for them.

Regards.

Mark

Mark and everyone else - thanks again for all your input. You are very helpful. I will give it a shot with the 55 grain 223 that is everywhere, and when I reload I will get a bit heavier projectiles. As I understand it, the 1:7 twist works better with heavier bullets but most military training with 1:7 twist barrels is with 55g projectiles so I shouldn't have too much trouble (hopefully).

Of course I expect a bit of initial break-in issues regardless.
 
Use lots of lube, the wetter the better. Preferably Slip 2000, or at least CLP, stay away from Militec, Remoil, etc. Refer to your manual on what to lube, and what not to. Also, it is not necessary to clean it after every trip to the range. Google "filthy 14".

1in7 is only "needed" to shoot tracer ammo, and not because of the weight, it is because of the length. Even the heaviest stuff will work with 1in8. 55 grain will be fine with 1in7. You don't need to go heavier to kill paper, unless you are looking a long range accuracy.

Regards.

Mark
 
i had issues at first with my 10.5 lmt cycling properly. i ran a few boxes of 5.56 and lots of clp and it now runs perfectly. I have put a few thousand rounds through it now and I cant remember the last time it had a problem.
 
My 14.5 ince MRP has eaten everything I've fed it without a single malfunction since day one (a wide variety of .223 and a few 5.56's).

As far as 5.56 goes... SFRC has the S. Korean PMC M855 (5.56 Green Tip) every now and then. And Henry at Budget Shooter Supply has had Federal XM193 (5.56 55gr) in the past. Both are great to deal with.

Hope this helps. Cheers.
 
10.3"/10.5" guns can be a little more particular than 14.5"/16" guns, especially in the beginning. It has to do with dwell time and gas port sizing. That is why some munufacturers don't make 10.5" guns.

LMT has mastered the art of the 10.5", but even Paul Buffoni (owner of BCM) has stated that his shortest barrel is 11.5" for a reason.

It is also why Claven, I (if I can include myself in this group), and a few others recommend AR newbs/virgins buy complete 14.5"/16 inch DI guns.

Regards.

Mark
 
As far as I know, BCM don't make anything shorter than 11.5" and when asked why, that was his answer.

What make is his 10.5"?

Regards.

Mark
 
I checked and budget shooter supply has some Norinco mil spec 5.56. Non corrosive, lead core. Does anyone have some experience with this ammo? Is it worth the while?
 
No issue with 223 in my LMT Defender 2000. .223 in 5.56 chamber is a go. No go the other way around due to the higher pressure of 5.56 ammo.

That's actually not the issue with .223/5.56 interchangeability. Any issues have to do with bullet weight and throat specifications. A 5.56 spec chamber has more freebore than a SAAMI spec chamber, which may cause an unsafe pressure spike when using 5.56 rounds firing heavier projectiles. In most cases, it is perfectly safe to interchange .223 and 5.56; however, if you do not know what circumstances could lead to problems, err on the side of caution and do not fire 5.56 from .223 rifles. The difference in pressure has to do with NATO and SAAMI using different methods to measure cartridge pressure, and does not necessarily mean that 5.56 spec cartridges produce a higher pressures than .223. For example, the CIP (Commission Internationale Permanente pour l'Epreuve des Armes à Feu Portatives) lists the max pressure of the .223 as 62,000 psi, the same as the max listed NATO service pressure.
 
I bought a couple of boxes (40rnds) of 5.56 just to try it. It shot fine threw my 7.5" 1/9twist bbl and felt like it had a bit more "punch" than regular .223 55gr. It came in a white box and may have been Koren.
Last I checked, Target Sports still had a suppy @ $9.99/20.
 
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