AR 15 accuracy

[KorbenDallas]

So I attempted to sight in my PSA AR 16in the other day at 50 yards and was only managing 4 to 5 inch groups with trs-25 red dot. It's a three MOA dot and was wondering how good of a group that is? I was using MKE ammo if that's a huge factor.

[Rightwinger]

Lots of factors here.  Dots are just that, a fairly big target area being shown.

 

What twist rate on the barrel and what grain on the ammo?  I ask because I was watching PSA for several months back when I was doing a "low cost" build and all they kept putting out was their 1/7 twist barrels which work better on the heavier grain bullets.  I prefer 1/9 for 55 grains.  Now the other factor not mentioned in the twist rate discussions is actual length of the bullets themselves while engaging the lands/grooves.  It is mostly covered in that a larger grain bullet, like a 70 to 75 grain is going to be longer and thus have more surface contact based on the same caliber size.  Were the holes perfectly concentric or did they keyhole?  If they keyholed with that spread, I'm betting you have a 1/7 and were shooting 55 grainers.

 

One other way to eliminate some of the data is to lock your rifle down in a bench rest so you remove the "shooter" from the equation.

[KorbenDallas]

Your exactly right. Why I didn't throw in it was 1/7 and using 55gr was stupid on my part. Unfortunately my knowledge of twist rates was limited until after I purchased the upper. While checking the target I seen one keyhole. I'm sure more bullets tumbled just that one stood up while passing through. It's tough to find heavier ammo for a decent price. What do you think about the hornady steel match 75 gr? I prefer brass but again price is a factor.

And besides switching ammo my only other option is barrel swap correct? Edited September 7, 2014 by jayyr15

[Rightwinger]

Yep but it's not necessarily hard nor a loss on your part.  Keep the 1/7 for longer range shooting and get you some 75 grain stuff (tracers are fun!) but buy you a nice 1/9 with a Wylde chamber and shoot the cheaper stuff when your not trying to go out past 250.

 

This group and the info on AR15.com can walk you through a barrel swap. Heck, several of us, including myself, schedule permitting can have you swing by and swap out barrels. 

[gregintenn]

Assuming you were shooting from a rest, in my opinion, a 4-5 inch group is unacceptable. Might be o.k. were you firing from an offhand position.

 

I believe a 1 in 7 twist barrel should stabilize a 55 grain bullet at 223 speeds. I would try some different ammo before thinking about another barrel.

 

Is your sight securely mounted?

 

Have you fired this ammo with open sights?

Edited September 7, 2014 by gregintenn

[173rdABN]

1/7 with 55's should be just fine. like Greg said, check everything else first.

[KorbenDallas]

Yep but it's not necessarily hard nor a loss on your part.  Keep the 1/7 for longer range shooting and get you some 75 grain stuff (tracers are fun!) but buy you a nice 1/9 with a Wylde chamber and shoot the cheaper stuff when your not trying to go out past 250.
 
This group and the info on AR15.com can walk you through a barrel swap. Heck, several of us, including myself, schedule permitting can have you swing by and swap out barrels.

  

Assuming you were shooting from a rest, in my opinion, a 4-5 inch group is unacceptable. Might be o.k. were you firing from an offhand position.
 
I believe a 1 in 7 twist barrel should stabilize a 55 grain bullet at 223 speeds. I would try some different ammo before thinking about another barrel.
 
Is your sight securely mounted?
 
Have you fired this ammo with open sights?

Thank you Rightwinger I will keep that in mind.

The sight is secure and I also tried my BUS with same results. This the first using that ammo but reading up on it MKE is supposed to shoot well for a light grain. I will try out some different ammo like you recommend because I'm not looking for match grade accuracy as I'm no where near a match shooter. It's more for plinking but I want to hit what I'm aiming at with decent consistency.

[TMF]

1/7 with 55's should be just fine. like Greg said, check everything else first.

Really? I've got two 1/7 ARs but only run 62gr and up. Was always told not to go below 62. I run 55s through my 1/8 and 1/9.

You have experience shooting 55s out to distance with a 1/7? ~300m?


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[gregintenn]

Lake City surplus, Remington, or if you could find one of the Federal Value packs, these all seem to be very accurate in any of my rifles.

 

 

Really? I've got two 1/7 ARs but only run 62gr and up. Was always told not to go below 62. I run 55s through my 1/8 and 1/9.

You have experience shooting 55s out to distance with a 1/7? ~300m?

300 meters? I believe the OP mentioned 50 yards. I wouldn't doubt a heavier bullet shooting a tighter group at extended distances with the faster twist, but at 50 yards, he should be getting better than 4-5" groups with 55 grain ammo.

Edited September 7, 2014 by gregintenn

[Rightwinger]

He needs to eliminate some of the variables.  Lock the rifle down and take out the shooter and the red dot as issues.  If rested it still shoots that poorly, it's ammo or twist.  Buying a box of heavier grain bullets can then fully find out where the issue is.

[Garufa]

For what it's worth, last weekend I went out with several varieties of ammo just to test grouping.  Rifle has 16" PSA upper with FN chrome-lined 1/7 twist barrel.  Shooting from a bag with an Eotech 512 sight at 50 yards.  Did not spend too much time letting the rifle cool down or getting all serious about holding the dot steady, breathing, etc.  Each target is 10 rounds and shot in the order listed.  The target dot is 1".

 

1.  Federal XM193 5.56mm  55gr.

2.  Wolf Gold .223  55gr.

3.  ZQ1 (MKE) from WalMart 5.56mm 62gr.  Yes, this ammo is essentially m855, even attracts a magnet.

4.  Federal XM855 5.56mm  62gr.

5.  PMC X-Tac 5.56mm 62gr

6.  ZQ1 (MKE) 5.56mm 62gr after adjusting sight.

 

Edited September 7, 2014 by Garufa

[RWF]

I bought a complete upper from PSA last year on sell for a build and did not want there receiver and the barrel nut was not even snug.

I never fired the upper as it was so I do not know how it would have shot.

just fyi

[Glock30]

Was this a complete PSA rifle? Did you buy it as components and assemble yourself?

 

Premium? Freedom? PTAC? These details matter, ya know. ;)

[KorbenDallas]

Was this a complete PSA rifle? Did you buy it as components and assemble yourself?
 
Premium? Freedom? PTAC? These details matter, ya know. ;)

This is the exact upper I purchased.
http://palmettostatearmory.com/index.php/review/product/list/id/14751/category/312

[Oh Shoot]

This is the exact upper I purchased.
http://palmettostatearmory.com/index.php/review/product/list/id/14751/category/312

 

Short answer is,  PTAC line is a YMMV thang, but certainly generally considered at least somewhat inferior to PSA's own builds using the FN manufactured barrels.

 

You'll note that PSA always puts somewhat of a disclaimer on the PTAC barreled stuff: "expected to group within the mil-spec". Which I believe is only around 4.5" 10 shot group at 100 yards with certain mil-spec ammo? Or maybe that has been tightened up with current standards, dunno,  will let others comment, that's just what sticks in mind.

 

I've read on other forums that PSA will indeed remedy any PTAC stuff if you convince them it isn't within mil-spec accuracy, but not sure what that takes exactly. Maybe you have to send it back and let them test shoot it or something, dunno what's "expected" of you to dispute the "expected" accuracy.

 

- OS

Edited September 9, 2014 by Oh Shoot

[KorbenDallas]

I plan another range trip with a few different ammo types before I make a solid judgment. And I understand I'm using a cheap upper with a cheap red dot and improper grain ammo for a 1 in 7 I cannot expect 2 in groups at 50 yards. I may just get a good quality chrome lined 1 in 9 if my problems persist. I don't feel like fighting PSA for a purchase six months and 400 rounds ago. I will repost here after next outing. Thanks for all the input guys I really appreciate it.

[Oh Shoot]

I plan another range trip with a few different ammo types before I make a solid judgment. And I understand I'm using a cheap upper with a cheap red dot and improper grain ammo for a 1 in 7 I cannot expect 2 in groups at 50 yards. I may just get a good quality chrome lined 1 in 9 if my problems persist. I don't feel like fighting PSA for a purchase six months and 400 rounds ago. I will repost here after next outing. Thanks for all the input guys I really appreciate it.

 

All else being equal, you won't get any significant diff between 1:7, 1:8, or 1:9 twist with 55 gr ammo, at least at 100 yards or less. Would be fractions of an inch if at all -- only a competition type shooter would much care.

 

General rule of thumb:

 

 

 

- OS

Edited September 10, 2014 by Oh Shoot

[atlas3025]

Were you shooting off a sandbag, or even a bench?  Where you shooting standing up?  No shame in not being a great shot...it definitely takes practice and technique.  It doesn't take much to really fling rounds around badly.  

[KorbenDallas]

Were you shooting off a sandbag, or even a bench?  Where you shooting standing up?  No shame in not being a great shot...it definitely takes practice and technique.  It doesn't take much to really fling rounds around badly.

I was rested on a bench, no bags just using the table for support. I will concur I'm not a great shot but I was making a good effort to stay on target and follow through but it very well may have been me. As hickok45 always says when the shooter blames the gun for poor accuracy it's usually the other way around. I may bring someone else me and see how they group also.

[atlas3025]

I was rested on a bench, no bags just using the table for support. I will concur I'm not a great shot but I was making a good effort to stay on target and follow through but it very well may have been me. As hickok45 always says when the shooter blames the gun for poor accuracy it's usually the other way around. I may bring someone else me and see how they group also.

 

 

More than once I have thought something was wrong with my rifle, only to have someone else show me it wasn't the rifle at all!  Hopefully you are the problem...that is really cheap to fix...fun too!   :cheers:

Edited September 10, 2014 by atlas3025

[BigK]

[quote name="jayyr15" post="1188309" timestamp="1410313903"]I may just get a good quality chrome lined 1 in 9 if my problems persist.[/quote] Primary Arms had this one on sale during Labor Day for $80, but even at $100 it's a steal. That is...if all the good things I'm hearing are true.

[sybo]

I shoot DIMES at 10 with my Sabre Defense! :rock:

[leroy]

I'm convinced ya may have handed us (...and you...) the answer in a post above... Ya need some sort of roll or bag to rest the reciever and barrel with if ya are shootin off a bench... The weapon needs to be hoisted up enough to where it (...including the magazine...) is not touching the bench in any way when ya pull the trigger.... Lots of time i'll use a roll under the front and a bean bag in the rear to rest the stock...

 

If ya do that and keep the rifle from contacting the bench, i think ya will be surprized at how the groups improve... The rifle needs to be supported the same way (...as much as ya can...) every time ya pull the trigger in order to check out their accuracy potential... 

 

leroy