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6/25/2017 7:35:25 PM
6/21/2017 8:25:40 PM
Posted: 11/3/2001 3:42:28 PM EDT
I have a Colt 16" Match Target. It is about a year old and has had less than 1,000 rounds through it.

I have a 100 and 160 yard range and two weeks ago I shot a 20rd group at 160 yards that was about 4 to 5". A group that I was very pleased with.

I ordered a scope mount, Armalite, and it arrived yesterday and I took the handle off last night and mounted a Leupold 1.75 x 6 Vari X III and couldn't wait to take it out this morning.

I sighted it in at 25 yards and I was making a jagged hole at 25 yards with 5 shots. They were all going in almost the same hole. When I started shooting at 100 yds to my surprise I wasn't even hitting the paper. So I put up a bigger piece of paper, 24 x 24" and still wasn't hitting the paper.

I tried Winchester Q3131A, PMP, Winchester 62gr power point, and Federal 69gr Match ammo. Ocassionally I would hit the paper maybe 2 out of 10 shots. I noticed that some of the holes were kind of jagged. After having shot another 10 shots, I hit the paper three times, I noticed that one hole looked as though someone had laid the bullet on its side and pushed it through the paper. I believe that the bullets are tumbling before they reach the target at 100yds.

I know this is not logical, but could taking off the handle and mounting the scope on the receiver have caused this problem? I looked at everything and that is the only thing I have done different. I was shooting off of sand bags to.

Does anyone have any ideas what is causing this?????

Any and all thoughts and suggestions will be greatly appreciated.
Link Posted: 11/3/2001 4:14:05 PM EDT

Originally Posted By Briar:
I have a Colt 16" Match Target. It is about a year old and has had less than 1,000 rounds through it.

I have a 100 and 160 yard range and two weeks ago I shot a 20rd group at 160 yards that was about 4 to 5". A group that I was very pleased with.

I ordered a scope mount, Armalite, and it arrived yesterday and I took the handle off last night and mounted a Leupold 1.75 x 6 Vari X III and couldn't wait to take it out this morning.

I sighted it in at 25 yards and I was making a jagged hole at 25 yards with 5 shots. They were all going in almost the same hole. When I started shooting at 100 yds to my surprise I wasn't even hitting the paper. So I put up a bigger piece of paper, 24 x 24" and still wasn't hitting the paper.

I tried Winchester Q3131A, PMP, Winchester 62gr power point, and Federal 69gr Match ammo. Ocassionally I would hit the paper maybe 2 out of 10 shots. I noticed that some of the holes were kind of jagged. After having shot another 10 shots, I hit the paper three times, I noticed that one hole looked as though someone had laid the bullet on its side and pushed it through the paper. I believe that the bullets are tumbling before they reach the target at 100yds.

I know this is not logical, but could taking off the handle and mounting the scope on the receiver have caused this problem? I looked at everything and that is the only thing I have done different. I was shooting off of sand bags to.

Does anyone have any ideas what is causing this?????

Any and all thoughts and suggestions will be greatly appreciated.




If you consider the scope is sighted on one plane and the barrel is on another plan. Both planes intersect at 25 yards. The barrel is below the scope and is angled up to cross the scope plane at 25 yards. The bullet passes this plane and continues up. My guess is you are hitting high. At 25 yards, this error is quite great.
Link Posted: 11/3/2001 4:37:46 PM EDT
I understand the concept you are talking about. If I was just hitting high all holes in the target should be in the same general area. However, they are scattered all over the target. One may be at the top, another one 14" lower, another 10" to the right. I honestly think I would have trouble hitting the "barn door" at 100yds the way it was shooting.

Thanks for the response.
Link Posted: 11/3/2001 5:03:01 PM EDT
[Last Edit: 11/3/2001 5:01:03 PM EDT by BKVic]
You've got a serious problem if your rounds are key holing. I use Q3131A and feel it is one of the better rounds you can shoot in your AR. Excesive throat erosion will cause your rounds to tumble but with only 1000 rounds through it I dont think that is it. You have a serious problem somewhere and may have to find a gunsmith to find what it is.

BKVic
Link Posted: 11/3/2001 5:52:25 PM EDT
I have never experienced this myself, but I have always heard that the heavier grain bullets are unstable if the barrel does not have enough "twist" to stabilize them. It has something to do with the rear end of the bullet being heavier and trying to get around to the front if not spun properly. I would suspect that out of my rifles(both are 1/9)that a 62grn would not perform as well as out of a 1/7. Am I right?
Link Posted: 11/3/2001 6:05:01 PM EDT
Link Posted: 11/3/2001 6:21:43 PM EDT

Originally Posted By rabbit:
I have never experienced this myself, but I have always heard that the heavier grain bullets are unstable if the barrel does not have enough "twist" to stabilize them. It has something to do with the rear end of the bullet being heavier and trying to get around to the front if not spun properly. I would suspect that out of my rifles(both are 1/9)that a 62grn would not perform as well as out of a 1/7. Am I right?



It should be fine out of a 1/7, the older 1/12 barrels should be unable to stabalize a 62 grain bullet.
Link Posted: 11/3/2001 7:29:03 PM EDT
Thanks guys. I normally shoot Q3131A that is what I shot the 4 to 5" group at 160yds with a week or so ago. When that wouldn't group at 100yds I tried the PMP, Winchester 62gr power point and out of desperation tried the Federal Match ammo. All of the above were all over a 24x24 piece of paper. The rifle has a 1:9 twist.

I went back to the 25yd range several times and each time with all the ammo listed above 5 shot groups were all about the size of a dime.

Good thing there is still a duck season. I needed another decoy weight.
Link Posted: 11/3/2001 7:39:21 PM EDT
I'd also check everything for tightness, then check it again. However you mount it, reciever, carry handle, whatever, it should still group with the same ammo if everything is consistently tight. Maybe you have scope issues? Try it on another rifle you know will shoot center, shake it and see if it rattles, etc. I went crazy with an SKS once that the mount was crooked on. Maybe check that. Bushmaster is not in business to make POS rifles, but I guess you could have always gotten "the one".
Link Posted: 11/3/2001 7:50:59 PM EDT
The bullets at 100yds appear to be tumbling before they hit the target and instead of making a nice clean round hole there are jagged holes in the paper and in one case it actually looks like the bullet went in perfectly sideways. The tip and base of the bullet are plainly visible on the paper.

I'm about ready to junk the damn thing.
Link Posted: 11/3/2001 8:03:44 PM EDT
You need to find a range with different ranges. and slowly move back. If the bullets are keyholing then yo need to really take a look at your barrel. .223 rounds if propertly stabilized shouldn't keyhole at 100 yds. meke sure it 1/9 and not 1/12. Try some 55grn rnds and see if that helps. If it keeps keyholing then you have a real problem. The real question is what if you go back to sight does it fix the problem, if it does then its not keyholing its just the scope setup. Hope you figure it out this sounds frustrating.

Guncrazy223
Link Posted: 11/3/2001 8:20:13 PM EDT
I had this happen:

I sighted in an I.O.R. scope on a 16” V-Match. I would get excellent groups at 25 yards, but at 100 yards I got the same results you are getting. I could not figure out what was happening until I realized I was impacting right if front of the target, and I was kicking-up dirt. The only thing I could figure is the sight plane and target plane had collimated. I.e., were running parallel. This would give you a nice group slightly below your point of aim at 25 yards, but would cause you to hit low at 100 yards. (I was impacting the ground because the bulls eye was only 8 “ above the ground.)
Link Posted: 11/3/2001 10:41:58 PM EDT
Found some more info and some intersting stuff about the .223, if it's true. www.firearmstactical.com/briefs13.htm "The older 55-grain M193 (M16A1) cartridge is not sensitive to rifling twist rate and can be fired in rifles with 1:12, 1:9 and 1:7 rates of twist. However, the newer M855 (M16A2) cartridge is best used with a rifling twist rate of 1:7 or 1:9. When the M855 is fired in a rifle with a slower rate of twist the longer 62-grain bullet can yaw up to 70 degrees in free trajectory through the air, substantially degrading accuracy"
the 1/9 should be fine for the 62grn, according to these folks. So WTF? I think I'm almost as frustrated with this as you are.
Link Posted: 11/4/2001 5:58:09 AM EDT

Originally Posted By Briar:
I have a 100 and 160 yard range and two weeks ago I shot a 20rd group at 160 yards that was about 4 to 5". A group that I was very pleased with.

I ordered a scope mount, Armalite, and it arrived yesterday and I took the handle off last night and mounted a Leupold 1.75 x 6 Vari X III and couldn't wait to take it out this morning.

I sighted it in at 25 yards and I was making a jagged hole at 25 yards with 5 shots. They were all going in almost the same hole. When I started shooting at 100 yds to my surprise I wasn't even hitting the paper. So I put up a bigger piece of paper, 24 x 24" and still wasn't hitting the paper. Also, if this is a handle mount and not a flattop, the trajectory of the bullet is going to rise more dramatically from 25 to 100 yards.



Hmm. First, check to be certain your mounts and bases are tight. Then set your 25 yard zero to be 1.5" low if this is a flattop, 2.5" low if this is a carry handle mount. This should get you in the same area code at 100 yds.



I tried Winchester Q3131A, PMP, Winchester 62gr power point, and Federal 69gr Match ammo. Ocassionally I would hit the paper maybe 2 out of 10 shots. I noticed that some of the holes were kind of jagged. After having shot another 10 shots, I hit the paper three times, I noticed that one hole looked as though someone had laid the bullet on its side and pushed it through the paper. I believe that the bullets are tumbling before they reach the target at 100yds.



No doubt about it. Buy a box of Federal Premium 55 grain Nosler Ballistic Tip varmint loads, or roll your own with 24.8-25.0 grains of H335 and a CCI BR4 primer. This should give you a modicum of accuracy to at least get sighted in.



I know this is not logical, but could taking off the handle and mounting the scope on the receiver have caused this problem? I looked at everything and that is the only thing I have done different. I was shooting off of sand bags to.

Does anyone have any ideas what is causing this?????

Any and all thoughts and suggestions will be greatly appreciated.



Seems perfectly logical that this be the cause of the problem. First thing, make sure the scope bell isn't hitting the handguard. If it is, this can really cause problems. Make sure your rings are tight and the base is tight. You might even try a different scope.

There is one last problem. I'm coming to terms with a Bushmaster with a really long throat designed to shoot heavier bullets. Smaller bullets that shoot well in other ARs with short throats just don't shoot at all in the Bushy - the leade is so long that the shorter bullets (55 or grain and smaller) can actually be out of the case mouth before they engage the rifling. This is terrible for accuracy and I have had experiences like you had. Maybe your rifle was on the edge of having too much leade and the 1000 rounds just pushed it a little too far. The answer is to use heavier, longer bullets as you barrel twist tolerates.

Keep us all posted, I for one would like to know what you find corrects the problem.

shooter
Link Posted: 11/4/2001 8:35:16 AM EDT
A couple of guys have said that they had a similiar problem and it was caused by the barrel not being tight. I took off the hand guards and as far as I can tell it is tight but I don't know how to check it. It appears that it may take a special tool for the barrel nut. Is the barrel nut the piece with the cut outs in it that the gas tube sets in?
Link Posted: 11/4/2001 8:58:02 AM EDT
Key-holing is not caused by adding a scope mount. Thoroughly clean the rifle and lubricate it in accordance with the -10, available for download from the link tacked at the top of the Maintenance & Cleaning Forum. Use Breakfree CLP OR LSA. One other cleaning step you should consider is the use of a good copper remover like Shooter's Choice or Sweet's 7.62. Follow the directions on the bottle to the letter.

Next, go to Tweak's Troubleshooting Checklist at www.ar15.com/articles/article.html?article=15. Follow that procedure to the letter up to test firing. Remove the scope and use the sights you were using for the original group. Use the Q3131A.

Fire at 25 yards and note your group size. Move to 100 yards and shoot another group.

If everything is working fine, go back tho 25 yards, remount the scope and repeat the shooting sequence, noting the results.

Come back here and tell us about it.
Link Posted: 11/4/2001 9:18:55 AM EDT
Briar, for what it's worth to you, I just got in from my range with the Bushy V-comp I mentioned in the above post. I used 69 and 77 grain Sierra bullets and even the bad groups were only about 1 1/2". This is a big improvement from Wednesday when I was spraying 52 and 55 grain bullets sideways into a 3 foot circle just like you. I really think you ought to try some longer bullets.

Shooter
Link Posted: 11/4/2001 12:08:36 PM EDT
Among the ammo I shot was a box of Federal 69gr Match. It did the same thing.

I'm taking it to a gun smith who builds AR's and see what he has to say. If in fact the barrel is lose I don't want to shoot it until someone a hell of a lot more knowledgeable than I am looks at it.

Thanks to everyone who took the time to respond. It sure is nice to have a place to go and helpful friendly people to talk to when things like this go wrong. I will let you all know what he has to say. Might just save someone else a lot of hassle and agrivation.
Link Posted: 11/4/2001 1:48:27 PM EDT
Briar,

Have you tried taking the scope off, and shooting with the handle on?

If you can Group OK with that, then it is probably in the scope and/or Mount.

Then take the scope off, and put a different one on, and try it. If the problem stops, it is in the Scope. If not, it is in the mount.

If it still groups badly with the carry handle sights instead of the scope, it is either the rifle or you. Have someone else shoot it and see what happens.

AFARR
Link Posted: 11/4/2001 1:50:24 PM EDT
And,

It is possible for the scope to be bad (even a Leupold). One of the lenses inside can be loose and move on firing. The reticle may be loose, etc.

Link Posted: 11/4/2001 2:55:27 PM EDT
It puts every bullet almost in the same hole at 25yds the way it is now. That leads me to believe that the scope is ok.

It might be me, but even on my worst day I can usually hit a tagret that is 24" x 24" more than two or three times out of 10.

Even if the scope is bad say at 100yds, that still wouldn't make the bullets key-hole would it?
Link Posted: 11/4/2001 3:19:49 PM EDT
Briar,

You are correct about the keyhole part. The scope MAY still be the culprit. Maybe the scope is angled too far upward--i.e. you are aiming at the target, but the rounds are bouncing off the ground. You might not see it at 25 yards, but at 100 yards, maybe you are.

You tried several grain weight rounds--if it tumbled with one, then it shouldn't with other weights. The post ban Colts are usually 1 in 7" or 9". That should stabilize all the bullet weights (esp. the 1 in 9") you mentioned.

Check the bore carefully--maybe the Chrome plating is shot, and is causing problems.

I would still take the scope off and try with the carry handle again. If it continues, then the rifle is the problem. If it doesn't, then it is the scope and/or mount.

These are keyholes:

(From shooting 62 and 68 grain rounds through a 1 in 12" FNC barrel on full auto at 25 yards)

Link Posted: 11/4/2001 3:20:27 PM EDT
Sounds like a bad barrel. Take a tight fitting patch and run it down the bore. Should be tight stem to stern. Another thing to consider is the mixing of bore cleaners. One of the most damaging combinations is Sweets and Shooters Choice. Even if you patch in between,the chemicals will react and etch the bore in no time flat turning your fly shooter into a POS even with stainless.

Easy fix.....replace the barrel.
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