Tight .223 barrel

[5thSFGroup]

I have an AR with a 1/7 twist on the barrel. This rifle absolutely hates Fiocci factory loads on both the .62 and .55 grain standard loads. I know this type of barrel favors a heavier bullet...but it loved my .55 grain Hornady bullets with a minimum grain load. It is very accurate with that load.

The factory loads on Fiocci blew one primer and put extractor marks in several other casings. Anyone else had this type of experience?

 

[longdayjake]

Is your barrel a 5.56 or a .223?

 

[AMG04]

I would check to see what your rifle is chambered in 5.56x45 nato or .223 Remington.

From what I understand the .223 chamber has a shorter throat and tighter chamber.
Whereas, 5.56x45 nato has a longer throat and an "larger" chamber to allow higher pressure mil spec loads.

.223 Rem can be safely fired in any rifle chamber 5.56 nato, but it is not advised to fire nato in a .223 Rem (pressure spikes).

This could explain what happended in your rifle.

 

[5thSFGroup]

The barrel was mag tested and is a 5.56.

 

[suzukisam]

your 1:7 should shoot just about anything 55 and up... now on the xtreme heavey end you may have problems and on the extreme light you may also...my 1:7s all shoot very well with 55s up to 75s...loading can be an issue, but the gun fires them well... people think you can over spin a 55 grainer and you can't really..

 

[5thSFGroup]

The majority of my plinking, when done with my loads, are a boat tail 55 grain. I bought those because they were on sale and work fine when I load them at the bottom end of the range. The rifle handles 75 grain Hornady rounds very well....again, I am using the bottom end of the scale. The only problem I ever had was on the factory Fiocci. Those rounds would not even group well when I was using a scope. I used some of my reloads and at 100 yards, placed them all with 2 inches.

 

[5thSFGroup]

Thanks AM. Your information was backed up by an article that I found. Since I do have a 5.56 bbl. I am still at a loss as to why the rifle reacted so badly to that brand and round.