Accuracy expectance [Archive] - Glock Talk


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02-16-2010, 15:50
I have 2 ARs, one is a Colt HBAR 1:9 twist and the other is a put together 18" 1:7 twist chrome lined. I loaded some normal 55 gr fmj. Nothing special, I think they are new mil-spec bullets. I know the 1:7 is better with heavier bullets but what kind of groups should I expect out of each of these guns with this non-match ammo at 100 yds? How much worse should I expect the 1:7 to shoot the 55 gr compared to the 1:9?

02-16-2010, 16:07
Accuracey is a realitive term when it relates to ar's, with many factors and variables. The Mil-spec ammo is supposed to get a three inch group at a hundred yards as a standard. If you reload you ammo you can make that shrink, considerably. Also what kind of trigger is in your AR, the trigger pull will make all the difference in the world. I have a jewell trigger in mine and I can shoot an inch to and inch and half in my 16" 1 in 9 twist carbine upper. I have a 24" 1-8 twist bull barrelled upper that puts the same 55 grain bullett in the same hole at a hundred yards. Different uppers, same bolt and carrier and the same lower. Hand loading and trigger, make the big difference in my oppinion.

02-16-2010, 16:11
I also wanted to add that I have heard but do not know for sure that chrome line barrels, decrease accuracy. Because the process for chrome lining the barrel, rounds the edges of the rifling, thus decreasing accuracy. The chome lining is ment for Automatic rifles to reduce fouling, when firing a high rate. Like the M16. Thus chrome lining is not needed in the AR 15.

02-16-2010, 16:41
Yeah, I was getting probably 4-inch groups with the 1:7, maybe 3 inch with the 1:9. This is with a mil-spec trigger and handloads. I am mainly an IPSC, comp. Pistol shooter so I am not very experienced in bench shooting whatsoever. I'm sure a lot of my problem is the trigger man

02-16-2010, 17:22
When it comes to combat weapons I've always taken the same approach; if you can hit COM at a reasonable distance for the weapon at hand shooting standing and a little bit better performance shooting from a supported position, that's good shooting.

I've always felt that when people talk about shooting MOA or sub-MOA, they tend to fail to mention that they are shooting from a bench or from a rest. This holds even more so when shooting open sights. I think of it as " if I was in a firefight, are most if not all of my rounds hitting COM on a normal sized person?" If your hitting your target consistently in the chest, your doing good.

This roughly translates to a 3-4".

Now if you shooting an accurrized rifle with a scope from a bench or prone position, that changes things.

02-16-2010, 18:27
Those are perfectly good "real world" groups. Run-of-the-mill chromed barrels aren't terribly accurate (probably 2-3 MOA average), and stock AR triggers aren't especially easy to shoot really well.

02-16-2010, 18:38
Thanks, I was trying pretty hard and went through about 120 reloads thinking I just suck (I still might). I hate reloading the .223 anyway but I guess I just need to suck it up and get used to it. I will say that since I got the Dillon case trimmer it has helped the morale of .223 loading. To reply to HLP I am only looking for COM just at longer distances eventually. I will see how that works with some 77 gr when I get a chance

02-17-2010, 03:29
I would actually say acceptable combat accuracy as within a 6" to 12" circle as that is about the average width of a human torso as it is presented to you in a combat situation. If you can put all your rounds in that area under combat conditions with people firing back at you and you possibly being on the move while shooting from non-optimal positions, you're way ahead of the curve in terms of coming out a winner in the firefight.

For bench and target shooting, then you get a lot more technical in whatever parts you are using to enhance performance and how good you are behind the trigger.

02-17-2010, 09:04
1/7" twist barrels shoot 55 grain bullets just fine.

You are not going to get the greatest accuracy out of standard .mil style 55 grain bullets.

I shoot 55 grain Federal, Winchester, Black Hills, etc. ammo through 1/7", 1/8", and 1/9" twist barrels in run and gun competition out to 425 yards on a regular basis and I can tell a difference in accuracy using a 3.5x ACOG or 1.5-5x Leupold.

When talking about accuracy, a few things need to be considered:

-Size of the target (ie. IPSC target or a prarie dog)

-Type of ammo (match vs. ball)


-Accuracy expectations

-Type of shooting you will be doing (ie. all prone shooting at static targets, running and gunning and shooting from unconventional positions, etc.)

I think many shooters get wrapped around the axel about mechanical accuracy instead of focusing on "practical accuracy".

This article may provide some food for thought in reference to accuracy:
03designgroup | Which Carbine Is More Accurate (

Hope this helps

02-17-2010, 09:37
I understand the practical accuracy concept, I regularly shoot 3-gun (HM) with an open sighted FAL. I am just aggravated that I don't seem to shoot much better with an AR w/ a 12x scope than I do with my iron sighted FAL. I think I just need more practice. Problem is that if I get a 4" group at 100 yds it's going to be hard to hit a 12" wide target at 300-400. Just really want to know it's possible so I have some confidence when engaging those targets

02-17-2010, 09:49
Try heavier match projectiles.

1/9" will shoot up to 69 grain projectlies reliably. Some 1/9"s will shoot up to 75's well, while a majoirty of them will not.

1/7" will shoot up to 80 grain projectiles reliably.

68's and 69's shoot well in both 1/9" and 1/7" barrels.

You may also want to try shooting supported from the bench (or prone) and sand bag the forearms (make sure the barrel isn't touching anything) and the buttstock.

Colt barrels are, as a general rule, fairly accurate for stock chrome lined barrels.

What manufacturer barrel is the 1/7"? Is this barrel a 20" that was cut down to 18"? If so who did the work? I have seen some cut down barrels that shot well, and others that didn't.

Hope this helps.

02-17-2010, 10:00
The 18" 1:7 is supposed to be a 20" FN cut down by CMMG. Whether I believe that, I don't know. Since it seems to shoot close to the colt match barrel (which wasn't exeptional) I'm hoping they did a good job. I was shooting from a rest but like I said these are stock triggers and I'm not the greatest rifleman.

02-17-2010, 10:17
The more I read it seems that 2-3" groups are to be expected with mil spec ammo out of a chrome lined 1:7 barrel, the rest is probably me. I am going to try shooting more this weekend and maybe use a friends lowe with a better trigger and see how that works out.

02-17-2010, 10:22
one of the things I have learned recently is bench shooting is much difference than 3-gun. It comes down to accurate ammo, good mechanics, and form.

Here is what I would do if I were you. If money allows, pick up a better trigger. CMC, AR-Gold, Geissele, JP, Wilson, Timney etc all make fine AR triggers. Then pick up a box of good ammo, Blackhills 69gr, Hornady match, Federal match etc.

Shoot your handloads with the new trigger, then shoot the match ammo with the new trigger. That will give you a good idea of what you and your gun are capable of. It will also show you if your handloads are accurate or not.

02-17-2010, 11:51
Here is a sand bag group from my DPMS at 50 yards.

02-17-2010, 12:43
I can do that at 25 yds, I have work to do, gotta reload the Sierra bullets I have