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Discussion Starter #1
Was going to order some 75 gr. 223, but I noticed that the heavier rounds usually carry a 'match' designation with them. I just want some because they are heavier. Any reason why I couldn't use them in a standard mini 14?
 

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I think it's going to depend mostly on the rate of twist. For a round that long it's probably going to take a 1:7 twist to stabilize them. Dunno what the twist is in a mini 14, though.
 

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Discussion Starter #3
I think it's going to depend mostly on the rate of twist. For a round that long it's probably going to take a 1:7 twist to stabilize them. Dunno what the twist is in a mini 14, though.
Thanks d, always learning something here. Your post made me dig a little and it sounds like mine 'probably' has a 1:9, so I think the heaviest I should go with is 62 gr.

Good thing I ask.
 

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I had a Sig 556 with a 1 & 7 twist that shot them real well anything from 69 and up it just loved. It would shoot 55 grain alright but not like the heavier bullets.
 

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Thanks d, always learning something here. Your post made me dig a little and it sounds like mine 'probably' has a 1:9, so I think the heaviest I should go with is 62 gr.

Good thing I ask.
I'm sure it would shoot the 75's. Might not be real accurate, though. Personally I think a 1:9 twist is a pretty good trade off. You can shoot the 62's or maybe even 65's, while at the same time the 55 gr shouldn't cause any abnormal wear. Evidently that was a problem with early 1:7 rifles with real fast rounds, but I would think you'd have to shoot a lot of them before that would become a problem. Check your caliber markings too - evidently some target model mini 14's had a .223 chamber, in which case you don't want to shoot 5.56 ammo in it. If it's the more common 5.56 chamber, then you should get better accuracy from 5.56 due to it's longer leade.
 

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Discussion Starter #6
I'm sure it would shoot the 75's. Might not be real accurate, though. Personally I think a 1:9 twist is a pretty good trade off. You can shoot the 62's or maybe even 65's, while at the same time the 55 gr shouldn't cause any abnormal wear. Evidently that was a problem with early 1:7 rifles with real fast rounds, but I would think you'd have to shoot a lot of them before that would become a problem. Check your caliber markings too - evidently some target model mini 14's had a .223 chamber, in which case you don't want to shoot 5.56 ammo in it. If it's the more common 5.56 chamber, then you should get better accuracy from 5.56 due to it's longer leade.
When you mentioned checking your caliber markings, I had to go look. I call it a mini 14, but I guess it's officially a Ranch Rifle, as stamped right behind the rear sight, along with .223.

I take it that when you say, 'the more common 5.56', you are referring to actual mini 14's
 

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When you mentioned checking your caliber markings, I had to go look. I call it a mini 14, but I guess it's officially a Ranch Rifle, as stamped right behind the rear sight, along with .223.

I take it that when you say, 'the more common 5.56', you are referring to actual mini 14's
That's what I was meaning. If it's marked 223 don't shoot 5.56 in it. The shorter leade can cause pressure to increase with potentially catastrophic results.
 

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I did a little looking on wikipedia, and it looks like there were many different variations - even of the Ranch Rifle itself. According to wiki starting in 2008 Ruger started marking the barrels with "Ranch Rifle" instead of "Mini 14." It goes on to say that this model will chamber both 223 and 5.56, but I wouldn't trust my face and hands to wikipedia. Might give Sturm Ruger a call and check with them just to make sure. Doesn't say "Wylde" on it anywhere, does it?
 

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I have a Mini 14. My owner's manual states it will shoot both .223 and 5.56mm . I think mine was made in 1999 judging from the serial number and doesn't have the scope lugs characteristic of the Ranch rifle.


On the Ruger website under FAQ's (frequently asked questions), you can find


Can I shoot 5.56 NATO ammunition in my Mini-14 or Ranch Rifle?

With the exception of the Mini-14 Target Rifle, which accepts only .223 Rem. ammunition, .223 Rem. and 5.56 NATO can be used in all Mini-14 rifles and Ranch Rifles.
Please note that "Military Surplus" 5.56mm NATO can vary greatly in its quality and consistency.


Emphasis is mine.
 

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Buy a box and try them, My EBR hates 55 but love's anything lighter or heavier, go figure.
 

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I think it's going to depend mostly on the rate of twist. For a round that long it's probably going to take a 1:7 twist to stabilize them. Dunno what the twist is in a mini 14, though.
Did you mean "For a round that HEAVY (not long) as the length is pretty much the same for any particular caliber. By the way, since bullet velocity will be WAY down due to the heavier weight, I would think longer shots would have a bunch more drop and be harder to get on target.
 

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I have both a Kel-Tec SU16 and an AR15 and both have 1:9 twists and both like 55 gr and I recently bought a few hundred rounds of 42 gr and that stuff is REAL accurate at 50 yds with irons sights in the AR at least. Both are good for either 223 or 5.56.
 

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Older Mini 14's had a 1-10 barrel twist. The recent rifles have a 1-9 twist.

1-10 probably will not stabilize a 75 gr. bullet.

1-9 is borderline and not reliable after 200 yards.

Go with a 69 gr. bullet no worries with either twist.
 

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Discussion Starter #14
I have a Mini 14. My owner's manual states it will shoot both .223 and 5.56mm . I think mine was made in 1999 judging from the serial number and doesn't have the scope lugs characteristic of the Ranch rifle.


On the Ruger website under FAQ's (frequently asked questions), you can find


Can I shoot 5.56 NATO ammunition in my Mini-14 or Ranch Rifle?

With the exception of the Mini-14 Target Rifle, which accepts only .223 Rem. ammunition, .223 Rem. and 5.56 NATO can be used in all Mini-14 rifles and Ranch Rifles.
Please note that "Military Surplus" 5.56mm NATO can vary greatly in its quality and consistency.


Emphasis is mine.
Thanks for the link Fib, interesting. What is your serial number series? Mine is 196-xxxxx.
 

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Did you mean "For a round that HEAVY (not long) as the length is pretty much the same for any particular caliber. By the way, since bullet velocity will be WAY down due to the heavier weight, I would think longer shots would have a bunch more drop and be harder to get on target.
No I meant bullet length, and they're not all the same. The 62gr penetrator rounds that the military uses have a steel core that's lighter than lead, so the bullet is longer. My understanding is that the stabilization issues are due to length, not weight.

Here's an M193 projectile (55 gr) compared to an M855 projectile (62 gr)

 

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From my own personal experience...

I've been interchanging 5.56X45 mm and .223 in the same rifles since 1970 (that's 42 years) with zero problems.

Been doing the same with 7.62X51 mm and .308 Winchester; same results...zero problems.

Other folks don't, each to their own.
 

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From my own personal experience...

I've been interchanging 5.56X45 mm and .223 in the same rifles since 1970 (that's 42 years) with zero problems.

Been doing the same with 7.62X51 mm and .308 Winchester; same results...zero problems.

Other folks don't, each to their own.
Which is fine if you've got a 5.56 chamber. And you might get away with it in a 223 chamber - and you might not. Here's the skinny from the wiki folks -

"The 5.56 mm NATO and .223 Remington cartridges and chamberings are similar but not identical. Military 5.56×45mm cases are often made thicker and therefore have less case capacity.[17] However, the NATO specification allows a higher chamber pressure. NATO EPVAT test barrels made for 5.56 mm NATO measure chamber pressure at the case mouth, as opposed to the location used by the United States civil standards organization SAAMI. The piezoelectric sensors or transducers NATO and SAAMI use to conduct the actual pressure measurements also differ. This difference in measurement method accounts for upwards of 20,000 psi (140 MPa) difference in pressure measurements. This means the NATO EPVAT maximum service pressure of 430 MPa (62,000 psi) for 5.56 mm NATO, is reduced by SAAMI to 55,000 psi (380 MPa) for .223 Remington.[18] In contrast to SAAMI, the other main civil standards organization C.I.P. defines the maximum service and proof test pressures of the .223 Remington cartridge equal to the 5.56 mm NATO.

The 5.56 mm NATO chambering, known as a NATO or mil-spec chamber, has a longer leade, which is the distance between the mouth of the cartridge and the point at which the rifling engages the bullet. The .223 Remington chambering, known as SAAMI chamber, is allowed to have a shorter leade, and is only required to be proof tested to the lower SAAMI chamber pressure. To address these issues, various proprietary chambers exist, such as the Wylde chamber (Rock River Arms)[19] or the ArmaLite chamber, which are designed to handle both 5.56 mm NATO and .223 Remington equally well. The dimensions and leade of the .223 Remington minimum C.I.P. chamber also differ from the 5.56 mm NATO chamber specification.

Using commercial .223 Remington cartridges in a 5.56 mm NATO chambered rifle should work reliably, but generally will not be as accurate as when fired from a .223 Remington chambered gun due to the longer leade.[20] Using 5.56 mm NATO mil-spec cartridges (such as the M855) in a .223 Remington chambered rifle can lead to excessive wear and stress on the rifle and even be unsafe, and SAAMI recommends against the practice.[21][22] Some commercial rifles marked as ".223 Remington" are in fact suited for 5.56 mm NATO, such as many commercial AR-15 variants and the Ruger Mini-14 (marked ".223 cal"), but the manufacturer should always be consulted to verify that this is acceptable before attempting it, and signs of excessive pressure (such as flattening or gas staining of the primers) should be looked for in the initial testing with 5.56 mm NATO ammunition.[23]

It should also be noted that the upper receiver (to which the barrel with its chamber are attached) and the lower receiver are entirely separate parts in AR-15 style rifles. If the lower receiver has either .223 or 5.56 stamped on it, it does not guarantee the upper assembly is rated for the same caliber, because the upper and the lower receiver in the same rifle can, and frequently do, come from different manufacturers – particularly with rifles sold to civilians or second-hand rifles.

In more practical terms, as of 2010 most AR-15 parts suppliers engineer their complete upper assemblies (not to be confused with stripped uppers where the barrel is not included) to support both calibers in order to protect their customers from injuries and to protect their businesses from resultant litigation."
 

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Not all 75 grain Bullets are created equal. The Privi Partizan 75 grain Bullet loaded in 5.56x45mm Ammunition is designed to work very very well in Rifles with the 1 in 9 twist and mostly okay in the 1 in 10 twist. I use it only in my Match AR15A2 with it's 1 in 9 Twist. Good Stuff!

As for the Ruger Mini-14, your Mini-14's serial number prefix will tell you what barrel rifling twist rate you have and Ruger probably has a Table of production configurations. For example: Both of my Mini-14's have 185 serial number prefixes. They and all the Mini-14's before them had 1 in 10 Barrel Rifling Twist Rates. Later 187 prefix series Rifles had 1 in 7 twist rates. Later 189 series had 1 in 9 twist rates, as the 187 series did not shoot the lighter bullets well. Etc.

For general Target use, I've loaded Hornady 60 grn FB-JHP's over H335 with good results. For general plinking and fun, anything I can get my mits on will do! For hunting, I like the CCI Speer 52 grain FB-JHP, as results on game have been.........explosive!
 
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So many variables with 5.56 and .223 and barrel lengths and bullet weights and powders and primers............the best is to try different ammo until you find the golden egg unless you reload.
 

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Did you mean "For a round that HEAVY (not long) as the length is pretty much the same for any particular caliber. By the way, since bullet velocity will be WAY down due to the heavier weight, I would think longer shots would have a bunch more drop and be harder to get on target.
As dbeardslee replied, length is a critical factor. There is an article titled 175 GROUPS FIRED, TWIST RATES AND ACCURACY on .223/5.56 and rate of twist in the April 2012 issue of Shooting Times, (p 50).

In addition to a detailed discussion about the effect of length on stablility, as well as the fact that a lead core will be heavier than a solid copper of the same length, the article has a picture of the some of the different bullets (below) as well as a table of results from shooting different bullets in barrels with different twists.

IMG_7092.JPG

IMG_7091.JPG
 
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