AR Question


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cyclopsshooter
September 6, 2009, 02:54 AM
Howdy all, I am looking to get into a varmint AR- I have an option to buy an Olympic PCR match grade from 2004. It has a 5.56 1-9 stainless steel 20 or 24 inch barrel. (i pulled the hand guards off and it is a FAT barrel)

I think the rifle will make a good platform and it will only cost 600- i think this to be the most bang for my buck option.

problem is, it has an A2 upper and i want a flat top for optics- I am thinking of buying an M4 16" upper and swapping the upper receivers (i want a lightweight carbine for plinking and brush carry- figured on the two uppers, switching them on the same lower)

the question is, to maintain accuracy, do i need a quality upper receiver or will any do? can i buy a cheap rock river or should i go with higher quality? are they all the same? are there better flat top uppers i should look at?

thanks:confused:

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cyclopsshooter
September 6, 2009, 03:02 AM
delete

R.W.Dale
September 6, 2009, 03:09 AM
the question is, to maintain accuracy, do i need a quality upper receiver or will any do? can i buy a cheap rock river or should i go with higher quality? are they all the same? are there better flat top uppers i should look at?


In my opinion NO with a couple caveats. Odiously you don't want some POS Vulcan/Hesse/Blackthorne garbage.

In reality other than the aforementioned Garbage and super high end uppers most everything in the middle is made by only a very few foundries

C-grunt
September 6, 2009, 03:21 AM
Instead of buying a carbine upper and taking it apart, why dont you just buy a flat top varmint upper from Model 1 sales, or somewhere like that. That way you'll have the flat top for hunting and a nice accurate irons gun.

C-grunt
September 6, 2009, 03:24 AM
OK so I just re-read your post.

Do you plan on just switching the upper receiver between the varmint and carbine, leaving you with a flat top varmint and A2 carbine? That sounds like a lot of work but should be good in the end.

cyclopsshooter
September 6, 2009, 10:26 AM
Do you plan on just switching the upper receiver between the varmint and carbine, leaving you with a flat top varmint and A2 carbine? That sounds like a lot of work but should be good in the end.

thats my aim

JDGray
September 6, 2009, 10:53 AM
RRA makes quality uppers, at least mine seem ok, and shoot great:)

Mot45acp
September 6, 2009, 12:10 PM
Do you have or know someone with the tools to do this? If not figure in the cost of barrel/free float wrench ($20.00) and action block (up to $50.00)

I'm assuming since the Oly has an A2 upper it has an A2 front sight base. Will you want to change it out to a low profile? With it being a heavy or bull barrel profile the FSB probably wont fit on your criteria for light wait carbine.

Do you want to free float it to squeeze that lil bit of accuracy out of it?

I guess my whole point is: Depending on how much work you want to do, it might be worth it to buy the rifle ($600.00 aint bad) and sell the upper or parts off it to fund exactly what you want.

W.E.G.
September 6, 2009, 04:06 PM
I assume you DO know the 1/9 twist is not a great choice for shooting heavier bullets.

If you are handy enough around AR's that you can pull two barrels, and re-install them without mucking-up one of the receivers, you are already equipped with the knowledge to do a good job.

I wouldn't call a Rock River upper receiver "cheap."
All you can really do with an AR upper is true the face so that the barrel nut bears evenly against the engagement surface. Whether that really makes any difference for accuracy is uncertain.

dubbleA
September 6, 2009, 04:48 PM
Sabre Defence makes a decent rifle and you can get uppers also. I have a complete varminter. I just tried some 75 gr Amax's and R-15 this past week.


100 yard group

http://i49.photobucket.com/albums/f268/dubbleA/Targets/IMG_0756a.jpg

400 yard group

http://i49.photobucket.com/albums/f268/dubbleA/Targets/IMG_0717-1.jpg

Mags
September 6, 2009, 05:03 PM
1/9 will handle up to 62 grain bullets pretty well. Since you are shooting varmints you probably will be using 40-50 grain bullets anyways unless you going after coyotes then 55-62 grain bullets will be fine.

taliv
September 6, 2009, 05:14 PM
nice, dubleA!

sabre does make nice stuff. what sights are you using?


OP: a good barrel is more important than the upper receiver in an AR. if you're working on a budget, focus on the barrel first.

R.W.Dale
September 6, 2009, 05:15 PM
1/9 will handle up to 62 grain bullets pretty well. Since you are shooting varmints you probably will ne using 40-50 grain bullets anyways unless you going after coyotes then 55-62 grain bullets will be fine.

What's the deal latelely with you guys saying it takes a faster and faster twist to shoot X bullet weight.

Last week I was reading posts saying that a 1-12 won't shoot 55 grainers and this week a 1-9 isn't enough for 62grn bullets:rolleyes: and all the while I have yet to own a 1-9" twist .223 that would not shoot a 75grn A-max or a 1-12" that won't shoot 69grainer HPBT's

Mags
September 6, 2009, 05:25 PM
Hey I just follow the directions listed on the manufacturer's box like a box of 62 grain Barnes TSX bullets says right on the box for a twist rate of 1/9 or faster.

Javelin
September 6, 2009, 06:02 PM
The real answer is that a 1/9 twist will stabilize 75gr. bullets. The realism is that the weight has nothing to do with it as it is the length of the bullet that matters.

Second point I want to make and really the only point I want to make is that there are many much better firearms than an Oly. With the recent firearms pandemic winding down to a close prices have collapsed. Look online and you can get a really nice AR for around $1000.

You don't need to have a 24" heavy barrel to shoot 5.56 either.. just a really well made barrel with flat top receiver. And though Noveske, LMT, etc might be a little out of your budget you can try looking at Bravo Company, Daniel Defense, etc. PM me if you have any questions.

:)

kwelz
September 6, 2009, 07:14 PM
Olympic = BAD.
For your purpose look at a RRA or Bushmaster. Some Mid level AR. Dont' buy Oly though.

ForneyRider
September 6, 2009, 07:16 PM
I shot .6in 5shot group at 100 yards with 75gr Hornady BTHP in a 1:9 twist AR. I shoot .488 with a 52gr bullet.

The 75gr A-Max might be too big, but the 75gr Hornady BTHP and the Sierra 77gr SMK should be okay. I have some 73gr Bergers.

The bullets with load data showing 2.26in COL or smaller should work pretty good in 1:9. Although, I load the 75gr to 2.28in COL and use a loading block.

For the "match" bullets 75gr A-Max, 80gr SMK, A-Max or Berger VLD, then use a 1:8.

For the 90gr, try 1:6.5 or 1:7.

KW
September 6, 2009, 08:09 PM
My own experience with 75 and 77gr match bullets in a 1:9 twist barrel was that the groups were opening up quite a bit vs. 68 and 69gr. Like 6" vs. 2" at 100 yards. But no two barrels are exactly the same, and air temp and pressure will play a part in determining if the bullets will stabilize properly.

cyclopsshooter
September 7, 2009, 12:55 AM
OP: a good barrel is more important than the upper receiver in an AR. if you're working on a budget, focus on the barrel first.
that is the main reason for buying the olympic- it has the perfect barrel for the varmint job

clarification- in the end i aim to have two uppers to go with the one lower- an A2 carbine and a A3 with optics- that way i can pick my rifle for whatever the day holds-

the traditional front sight shouldn't interfere with the optics, i plan on leaving it there

i work at a gun shop, my boss has all the tools- yes, i ask him questions too :)

thanks guys, i appreciate all of the insight and welcome any more

ForneyRider
September 7, 2009, 02:30 AM
Berger has 1:9 twist recommendation for the 70gr, 73gr, and 75gr bullets for .223.

If I am not under .5in with the 73gr, I will go back to 69gr SMK or Nosler CC or a 64gr Berger. Remington makes a 62gr match bullet.

R.W.Dale
September 7, 2009, 03:12 AM
Hey I just follow the directions listed on the manufacturer's box like a box of 62 grain Barnes TSX bullets says right on the box for a twist rate of 1/9 or faster.

And Barnes bullets are made out of what metal instead of lead?

Copper

Copper is less ____? than lead

Dense

So a bullet made from a less dense material compared to lead at the diameter and weight would have to be _____?

Longer

and a LONGER bullet takes a faster ____ rate to stabilize.

Twist

Kman
September 7, 2009, 12:05 PM
Your question is easy to answer, Rock River makes some of the best AR equipment, the receiver will be just fine, but I have to ask,,ever swapped barrels before?

Maverick223
September 7, 2009, 01:05 PM
Last week I was reading posts saying that a 1-12 won't shoot 55 grainersI get the feeling that you are referring to me...and I did NOT say that. I said that anything above 55gr (in a 1/12 or 14) was hit or miss. :)

Mags
September 7, 2009, 10:10 PM
Quote:
Originally Posted by The Real Mags
Hey I just follow the directions listed on the manufacturer's box like a box of 62 grain Barnes TSX bullets says right on the box for a twist rate of 1/9 or faster.

And Barnes bullets are made out of what metal instead of lead?

Copper

Copper is less ____? than lead

Dense

So a bullet made from a less dense material compared to lead at the diameter and weight would have to be _____?

Longer

and a LONGER bullet takes a faster ____ rate to stabilize.

Twist
__________________ So a 62 grain bullet is not reccomended for a slower rate than 1 in 9 like I said earlier. So what was your point other than being an ass?

R.W.Dale
September 7, 2009, 10:13 PM
So a 62 grain bullet is not reccomended for a slower rate than 1 in 9 like I said earlier. So what was your point other than being an ass?

:banghead::banghead::banghead:

That the bullets you have are the ONLY 62grn bullets that require a 1/9" twist to stabilize. That bullets made out of LEAD will shoot in slower twist rates for the same weight because they're SHORTER

Wayne G.
September 8, 2009, 01:55 AM
Cyclops,

Check out Bravo Company USA. BCM uppers are hard to beat. $475.

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