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Range Report: I mounted a 3 to 9 Burris fullfield II on my new AR and went to the range today. At 100 yards I got some decent groups.

Federal gold medal match 69 sierra matchking HPBT shot like crap, 3.5" groups.

Federal American Eagle Red box 50 gr HP, 1.2" groups.

Generic 55 gr spitzer (don't know the ammo brand, were given to me), 1.4" groups.

Winchester 55 gr power points, 0.9" groups

This was a average of three groups per ammo and were three shot per group.

I do want a free float forend because this AR shot better when the front rest was on the bags close to the receiver.

what barrel do you have? what is the twist?

if federal GMM 69s shot bad, there is certainly an issue with the gun.

I'm betting the barrel twist is stupid slow like 12 or 14.....

Free float forend won't make it shoot the wrong bullets better...

Generally a floated handguard doesn't help measurably until you start with bipods, slings etc...

I'd try some 40s if you can find em. Saw a friends mis labeled gun do the same thing... cleaning rod then showed a really slow twist...

Take the scope off and try another.

seeing it produces sub inch groups with lihgt bullets.... I"m betting its not a scope issue.

right, poor reading, then back to barrel.

Given the mount, 3 shot groups and a no name kit, I'm not betting on anything.

parts is parts!

I don't see the mount mentioned. The burris scopes are a little known value....but anyone can snub em as needed.

He said an average of three, 3 shot groups. More shooting isn't going to change the average enough that its going to skew this post.

Barrel twist... GMM should shoot as well as the others and actually quite a bit better.

Off the top of my head, the only time I've seen whats reported above is a twist issue.

YMMV.

Ooops, I got this one confused with the $29 UTG QD mount, missed the 3, 3 shot groups but a $269 upper doesn't instill confidence.

Well I now see that he cancelled the $269 upper and ordered a PSA 1/8 SS barreled upper.

Without being condescending, I noticed you do shoot a bolt gun well and will add that shooting an AR has a few minor quirks. Maybe a little more range time with the AR will cut the group size down. Just curious, was the 69 gr stuff the first ammo tried?

Twist issue, that would be my guess.

Why twist?
A 1/8 twist and 69 SMK is like peanut butter and jelly.

Who said its an 8 twist? Point being it might be advertised and even stamped as such... but until you measure it you never know. EVER.

I've seen twists stamps be wrong 3 times in life so far. Once on a very expensive custom barrel from a TOP barrel maker that supplied/supplies barrels to a ranked national high power shooter...

It happens, no biggy, just check it and move on.

Would a 300 buck upper shoot bad or good? I"m about tired of all the flogging out there.... a high dollar upper is more guaranteed to do well, so to speak, but I've seen so many examples of cheap uppers shoot to MOA give or take its amazing.

TWR makes a GREAT point in the fact that an AR is a bit quirky to shoot well, but unless the GMM was first and he got used to the gun, it still says barrel twist.

PRobably helps I"m adamant because a great friend and mentor had the EXACT same issues from a cheap model one sales upper he bought for a truck gun in the dusty pastures.... shot like crud with all our 69 match loads.... we had to dig for light bullets, actually had to go buy some... finally I don't recall the actual measured twist but the cheap junk upper was mis stamped and when he figured that out, it shot 40s around or even under MOA....

All the above said i'm not about cheap uppers or guns generally speaking, but I"m not naive enough to proclaim they can't or wont' work.

I'm curious as to twist and stabilization. Does a slow twist throw wide patterns but make perfectly round holes or will the unstable bullets key hole?

I've seen that happen two times and it was obvious.

If I'm not mistaken a 1 in 10 will stabilize a 69 SMK and I've had a 1 in 9 stabilize 77's.

And if a slow twist causes poor groups with heavier bullets, why doesn't a fast twist do the same with light bullets?

Serious questions.

Ok Nimrod,
We're all on the edge of our chairs waiting for you to verify the twist.

Git 'er done.

I suspect this can be called voodoo. I've had some fast twist ones shoot lighter bullets not so well. I've had them puff a few too, but thats different.

To slow of a twist has always keyholed the bullets for me, but its so minute its hard to see if you are not really looking for it.

We had a 10 twist that would not shoot 69s once years ago. It was actually a 10 also as checked, but I've had 10s since that did just fine.

A buddy of mine shoots 9 twist on purpose, 20 inch tubes, and he runs 80s at 600 and beyond. He has never had an issue but he has also said he knows he is on the ragged edge most likely.

I would think that in this issue the 69s would be keyholing just a bit since they are not grouping well.

In this instance I just don't see how it can be anything but the barrel issue. You can't have ammo shooting snug groups, IE 1-1.5 inches appx at 100, and then come along and a PROVEN load and PROVEN bullet be heading towards 4 inch stuff.. That just should not happen.

BUT as we all know, sometimes things just happen. Maybe its not the twist, but having seen that a few times, thats what makes me stand firm on betting this is the same thing.

And I could easily be wrong.

I was fortunate that when we were shooting, we shot a LOT, knew a lot of folks, helped a lot of folks, loaded and shot lots of ammo and when you shoot almost every weekend in different locations across TX and the US even, you have a lot of exposure. Where it not for that some things I'd have never seen with my own two eyes.

Now if the barrel shot FGGM and the others all to around 3 inches give or take, I wouldn't nearly be as sure that it was likely a twist issue, but rather an issue with QC somewhere in the gun/barrel....or even could assume the shooter was not up to snuff.

Thanks, that makes sense, key holding at 100 May not be as obvious as it would be at 300.

I have seen it be sneaky at 300 even. 90 jlks in a full 7 twist Krieger... the holes were maybe .244 vs .224 diameter or something like that. Looking at them they just looked a tiny bit weird....

Which led me to having John talk Pac Nor into doing a 6.5 twist. Never saw any stability issues after that.

Sometimes this whole thing is full of voodoo type stuff.

Its one reason my take on things is what is the paper showing you result wise? If its good enough, why worry about if it should or should not work. Or if its done by others. Or if its popular. Or if the chrono says it should suck.

When I started I was on your side about top of the line being the only ARs... Colts where what you started with if possible. Then you had to swap a lot of parts out to make them match guns.

But over the years even the cheap stuff has, while usually looking ugly and mismatched, been able to function. Or function with only replacing something minor, and easy to replace. And still coming in way less than a baseline colt in the process. And somewhere there they managed to end up with barrels that were commonly shoooting 2 inches and under at 100...and these days its rare to see anything halfway decent that you can't get a load to shoot an inch at 100 for 5 shot groups. Factory ammo can be another subject altogether.
Though there are 2 factory loads I've never seen make me unhappy, 60 Fed GMMM, (never shot any other Federal load FWIW) and HSM 69s. Followed by the reload recipe of LC brass, 25 to 25.5 Varget, and a 69 SMK with a BR4 primer.... if that load didnt' shoot well enough to start with you had other issues.

The first I saw keyhole was M855 in an old Mini 14. (I know, how could I tell)

The other was a 17 Remington with 25 gr bullets and a slow twist, 20's shot great. So ya, voodoo all the way.

Then I've seen bullets that a barrel just didn't like for no apparent reason.

I don't know about top of the line, I've just seen better results with quality parts and guns. I've also seen and fixed enough cheap junk that I hate the thought of it. Threads that start out with what's the best AR for under $600 worry me. Maybe they will function just fine but more times than not, they don't, if they are shot enough.

Then again I spent $85 for a hammer the other day so maybe I'm nuts...