55 gr or 62 gr

jobbass

jobbass

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Hello,

Shooting those 2 bullets 55 gr or 62 gr (223 Rem) out of a 1:7 twist barrel,

What you guys think. It will be acuurate , nice groups @100, 200, 300 yards.

Thanks.
 
According to the trajectory and ballistic charts, you shouldn't notice much (or even any) difference out to 300m if it's a calm day. Beyond 300m the 62 gr should perform much better though.
 
No way to tell just by theory. You have to try them both to see which one your rifle likes best. I read and re-read Patrick Sweeney's books and he tested many ARs and they had different favorite rounds. My personnal opinion is that there are way too many thing happening and factors when firering to foresee the precise result.
 
jobbass said:
Hello,

Shooting those 2 bullets 55 gr or 62 gr (223 Rem) out of a 1:7 twist barrel,

What you guys think. It will be acuurate , nice groups @100, 200, 300 yards.

Thanks.
Click to expand...

Define nice groups?

If you are looking to wring as much from your AR as you can, both suck equally.
Any off the shelf match bullet from the major manufacturers will run circles around those two bullets at those distances, and beyond.
If you are looking to go no further than the 300 yard line, I'd look at the 69gr. smk and the Hornady 68 gr. HPBT.
 
Personally I think the 62gr commerical ammo is a waste of time for the premium over the regular 55gr- the 62gr SS109 with a steel tip is more like the 69gr SMK in shape than the all lead 62gr bullet. The all lead 62 gr bullet is more comparable to the bullet used in the GP90 of RUAG - in my limited experience, it runs out of steam after the first 300m.
 
greentips said:
Personally I think the 62gr commerical ammo is a waste of time for the premium over the regular 55gr- the 62gr SS109 with a steel tip is more like the 69gr SMK in shape than the all lead 62gr bullet. The all lead 62 gr bullet is more comparable to the bullet used in the GP90 of RUAG - in my limited experience, it runs out of steam after the first 300m.
Click to expand...


FWIW the BC of the GP90 is .331, their Target load uses a 69 BTHP and they show it having a BC of .309

See RUAG Ammotec website data sheets for info.
 
I was under the impression that:

1/7 twist = 55 gr.
1/9 twist = 62 gr.

If you fire 55 gr. out of a 1/9 twist barrel the projectile will start to tumble after extended ranges due to the rate of twist vs buller weight...anybody else?
 
Pietro Beretta said:
I was under the impression that:

1/7 twist = 55 gr.
1/9 twist = 62 gr.

If you fire 55 gr. out of a 1/9 twist barrel the projectile will start to tumble after extended ranges due to the rate of twist vs buller weight...anybody else?
Click to expand...


you got it backwards. and no the 55gr won't tumble at all.

62 is a waste of monry. it is more expensive and the stopping power on paper is the same. no if you were shooting for accuracy, then you do custom loads anyways.

just stick to 55gr.
 
The only 62Gr Id take is SS109 or M855 which have a longer bullet than the commercial factory 62Gr stuff.

I shoot factory 55Gr and anything heavier are handloads..
 
I always think the argument over 55gr or 62gr is silly because there are so many different types of bullet now. What you really should be looking at is the bullet length and work out the rifling twst from that.

If you're talking about the M193 55gr bullet vs. the FN SS109 bullet then it's a more specific question.

But the BC of the various 62gr. bullets around the world differs considerably.
 
The 55 grain bullets will be stable in a 1:14" twist barrel and 1:12 twist will stabilize a 62gr lead core bullet. One theory is best accuracy is often the minimum twist that will stabilize the bullet you want to use. That theory does change a bit if you go really, really long.

In really fast twist barrels (1:7) you usually can't shoot light bullets to high velocities unless they have thick jackets, because they can self destruct due to centripetal forces. In a 1:7 barrel a bullet at 3,400 fps is spinning at 350,000 rpm.

22 Hornet was historically 1:16 for use up to 45 or 50 grain bullets.
 
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If you want some anecdotal data, I have been practicing with the iron sights on my 16" 1/7 twist AR on gongs at 200-300m.

I can ring the hanging gong most of the time at 200m with winchester white box 55gr.

At 300m I could not seem to ring the gong with the 55gr, but at the end of the session I switched to my 69gr handloads and suddenly I could hit it as well.

Of course a number of things could have been causing this, including me just plain shooting a little better by the time I pulled out my 69gr rounds.

There's some anecdotal info for you, for what it's worth (This data is a little bit better than if I just pulled it out of my ass, but not by much.)
 
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