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8/22/2026 12:15:27 AM EDT
If I were to go deer hunting with modern M193 ammo from a 1:14 20" barrel, how would the bullet perform?
8/22/2026 12:59:37 AM EDT
[#1]
Not a good deer bullet.  

No expansion, tends to yaw and not penetrate in a straight line

5.56 can be a marginal deer round.  But not with a 55gr fmj

If you had to use it in a survival pinch, you'd want to hit head/neck.  Or a lung shot.  But nowhere near a real big game round
“All things are said already, but since no one is listening, it is always necessary to start again.”
8/22/2026 1:46:01 AM EDT
[#2]
That 1/14" twist is what the ar15 started with and it wouldn't  stabilize the 55 gr m193 bullet.  They switched it to a 1/12" twist.  If you reload or can find a solid copper 50gr projectile try that instead.  Barnes may make one.
8/22/2026 6:21:05 AM EDT
[#3]
FMJ is illegal for deer hunting in most jurisdictions.

That 1:14 twist barrel would probably prefer a lightweight 45 - 50 grain varmint bullet.
8/22/2026 8:00:32 AM EDT
[Last Edit: Combat_Diver][Edited] [#4]
My 1:14 stabilizes 55gr M193. Army change to 1:12 not for the 55gr M193 but for the longer M196 Tracer in cold artic air same situation as M855/M856 in M16A2

M193 will fragment from a 1:14. FMJs legal in NC for hunting, just no full auto.  But concur use a better projo or limit your shots to a sure CNS shot
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Iraq: 91,03,04,05,06,08,09,15,16,22-26'
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8/22/2026 9:15:53 AM EDT
[Last Edit: lysanderxiii][Edited] [#5]
Quote History
Originally Posted By 308223:
That 1/14" twist is what the ar15 started with and it wouldn't  stabilize the 55 gr m193 bullet.  They switched it to a 1/12" twist.  If you reload or can find a solid copper 50gr projectile try that instead.  Barnes may make one.
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Quote History
Originally Posted By 308223:
That 1/14" twist is what the ar15 started with and it wouldn't  stabilize the 55 gr m193 bullet.  They switched it to a 1/12" twist.  If you reload or can find a solid copper 50gr projectile try that instead.  Barnes may make one.

Over simplification, and partially incorrect.

The 55 grain bullet was marginally stable in the 1-14 twist.  It worked acceptably at hot temperatures, but became increasingly inaccurate as the temperature dropped.

It also was highly dependent on the particular bullet design.  In the early days of M16 development, the exact shape of the bullet varied.

Originally Posted By Combat_Diver:
My 1:14 stabilizes 55gr M193. Army change to 1:12 not for the 55gr M193 but for the longer M196 Tracer in cold artic air same situation as M855/M856 in M16A2

M193 will fragment from a 1:14. FMJs legal in NC for hunting, just no full auto.  But concur use a better projo or limit your shots to a sure CNS shot


At the time of the Arctic testing in 1962 or 63, there was no tracer round.  The 55 grain bullet from a 1-14 in arctic temperatures is extremely inaccurate due to lack of stability.

Many think as soon as the stability factor drops below 1.0 the bullet starts to tumble and key hole immediately.  Not so.  All a stability factor less that 1.0 means in bullet yaw increases with time, rather than decrease.  It may take several hundred yards before the yaw become so bad that tumbling occurs.  It also has a lot to do with the bullet shape, long skinny bullets will have less yaw when they finally upset, short fat bullets (like the final version of M193) take longer.  That part of the equation, how fast it departs, is the dynamic stability, something rarely discussed.

From a BRL report on M193 tested in 1-12 and 1-14 barrels:

". . . For the same bullet (M193) launched from a 1:14 in. twist barrel, S has a value of about 1.14 at 70°F and about .85 (theoretical) at -65°F.* As the gyroscopic stability factor (S) approaches unstable values, the flight characteristics of the bullet will deteriorate and could drastically change."


______________
* at standard atmospheric pressures and density.
8/22/2026 10:36:26 AM EDT
[#6]
Just remember... not all 55gr FMJ bullets are made to USGI specs... Jacket thickness , etc.

There have been plenty of 55gr FMJ bullets with thicker jackets that do NOT fragment at all.
*Hold on to your AR-15s. Their magic must be very powerful, or they wouldn’t want them.*
JAFOM.... Just another fat old man.

________________________________

TOGC,IADC
8/22/2026 10:40:01 AM EDT
[Last Edit: dalle0001][Edited] [#7]
Quote History
Originally Posted By bfoosh06:
Just remember... not all 55gr FMJ bullets are made to USGI specs... Jacket thickness , etc.

There have been plenty of 55gr FMJ bullets with thicker jackets that do NOT fragment at all.
View Quote


Yeah, really you're going to need to chrono it and gel test it to see how it performs. The M193 relies on velocity to maximize damage since it needs to pitch and yaw once it hits a target. It needs to go minimally 2700 fps, if I remember correctly. Federal, IMI, and Winchesters are really the three brands that are true spec M193s and some of the other brands too but it is hard to tell.

But as others said here, it is not a good deer round. You'll need something more of a soft point or some such for a white tail deer and usually those are in the 62+ gr areas. Just get the proper 1:9 or faster twist rates.
8/22/2026 11:22:08 AM EDT
[Last Edit: cttb][Edited] [#8]
It is illegal to hunt deer in Georgia (and many other states) with non-expanding bullets, which includes FMJs. Even if legal, hunting deer with xM193 is a bad idea. Even with a good shot, the deer is likely to run out of sight with no blood trail.

A 1-14 twist .223 is a varmint rifle, not a deer rifle. You need something else for deer hunting, preferably larger than .224.
8/22/2026 11:39:05 AM EDT
[#9]
I would use the Black Hills 50 TSX load if you have to use that barrel. It’s not technically legal here but if that bullet will stabilize it will perform way better than what you’re contemplating.

It’s insanely expensive.
8/22/2026 11:55:54 AM EDT
[#10]
Originally Posted By EagleArmsHBAR:
If I were to go deer hunting with modern M193 ammo from a 1:14 20" barrel, how would the bullet perform?
View Quote
8/24/2026 7:52:55 AM EDT
[#11]
Quote History
Originally Posted By micmac:
Not a good deer bullet.  

No expansion, tends to yaw and not penetrate in a straight line

5.56 can be a marginal deer round.  But not with a 55gr fmj

If you had to use it in a survival pinch, you'd want to hit head/neck.  Or a lung shot.  But nowhere near a real big game round
View Quote


5.56 is more than enough for deer. People use it effectively on elk and bear. But not fmj lol.
8/24/2026 8:07:27 AM EDT
[#12]
get a 6.8spc upper for deer hunting

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