Shooting unreasonably high

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Erickson5006

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I finally got myself a magazine for my bastardized/sporterized old Ljungman AG42b. And I can't hit anything. It's shooting 5' high at 200 yards. Wasted half a box trying to ring a 36" gong.

For starters, I can't find a taller front sight. This thing came with a 7/8" ramped blade in the front, and I don't want to throw away the original rear sight.

If I need a goofy tall front sight, where can I find one?

Also, how can I check that my barrel is straight?

Also, how can I check that the chopped off 20" barrel was crowned properly by Bubba?
 
go to marble sights web sight.they have a formula to tell you how high the sight needs to be.i got a front sight from brownells.several sights on here have sights for sale also.as for the barrel and crown,not sure other than getting a gunsmith to look at it
 
Checking for straight - done by eye looking through the bore. Hang a string or light cord in front of a window - align bore with that - you will see a shadow line through the bore - rotate the barrel - that shadow line will stay straight if the barrel is straight. Barrels often "straightened" using this technique - I have pictures of it being done in Remington plant and Anschutz plant. If your shadow line shows a curve or a kink, that is the point where your barrel is bent. Corlane's in Western B.C. straightened a barrel on my brother's 300 Win Mag after he bent it rolling his quad - I believe that is how they did it, but was not there to see. The straightened barrel shoots excellently - regularly used on targets out to 600 yards, without issue.

Assessing the crown - the part that "counts" is the exact point where the barrel looses contact with the bullet - the more broader muzzle is of less concern - that last contact edge must be concentric and perfectly square all around to the centreline of the bore. Not uncommon to find a barrel that the bore is not perfectly centered within the barrel - if a "crown" is turned to look good with the exterior of the barrel, there will be a non-concentric - uneven - release edge at the bore entrance, if that bore is not perfectly centered. Some rifles - .22 rimfire? - show a burned powder star on the muzzle after firing - growing off of the lands - an even star means the bullet release was even - not sure it is always visible on some centre fire cartridges...

I do not have enough experience on consequences of uneven release point - my own rifle threw poor groups - random - scattered - re-doing the muzzle end reduced group size significantly - I do not recall what was going on for direction though - do not recall that the bullets going wildly but in same general direction. I had hacksawed that barrel to be shorter, then smoothed off the end with a file - lousy groups. I used a piloted hand crowning tool from Brownells to "touch it up" and was then getting multiple 3 and 5 shot groups well under one inch 100 yards - huge difference! Was a Rem 788 in 243 Win.

An acquaintance borrowed my crowning tool - had a pilot made up for his bore - on a rifle he was working on was very obvious after starting that the "crown" was very much not concentric - significant amount peeled from one side before he got a smooth cut that went all the way around the bore. Had looked fine before, so just "looking at it" might be deceiving...
 
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take a peek at the rear sight, they are graduated for two types of ammunition, I forget exactly how, but you can disassemble it and reverse the drum for either heavy round nosed or lighter spitzer type bullets. Try both that and emulating the correct type of ammunition and it should be right on.
 
Ive tried switching the rear, and its not a huge difference.

The original sights are crazy tall on these rifles, so maybe this blade idea was never gonna work. I dunno who would put this much effort into modifying a gun and never have it shoot even close to 0.

I dunno how the front sight attaches and cant find much in my searches. But might need to find original style
 
I clicked the link in Post #8 - took me to a picture of a muzzle - not so sure about what I see - I was expecting to see lands and grooves right at the exact rim of the muzzle and the bore - you may have an opportunity there?? With a hand crowning tool and a pilot that fits snugly, it is a couple minutes to "square" and "sharpen" that edge. I am now doubting that can explain 5 feet high at 200 yards, unless part of a 8 foot to 10 foot diameter group at 200 yards??? Some militaries provided a "pull through" for cleaning - others provided a cleaning rod - sloppy use of either can result in the last bit of rifling in the bore, at the muzzle, being worn away by allowing the cleaning apparatus to rub against the rifling - was commonly addressed by "back boring" - I do not know if any militaries did that - essentially creating a new muzzle an inch or even two inches back inside the barrel, where the rifling is still good. I have never done that myself, but had a rifle that had that done to it.
 
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What i was originally taking a picture of was the fact that it isnt a perfectly symmetrical circle. Is a chopped-by-Bubba barrel supposed to be a little oblong? I cant seem to get a better picture than that with my Iphone.
 
I was thinking. Have you tried to shoot a group - 4 or 5 careful shots from a good rest - aiming at the same point?? 50 yards - 100 yards - should not really matter initially - a 2 foot group at 50 yards is knowledge that you might not have now? I have a BSA rifle that shoots 4 and 5 inches groups at 25 yards - no point "sighting in" - have to resolve whatever is ailing it first - but knowing what kind of group it shoots with your ammo is a good place to start to be able to gauge improvement or not. Does not really matter where the group is compared to where you are aiming - that is just a matter of adjusting your sight to match the impact point - but need to understand what you are starting from in the first place.
 
I mentioned earlier that not unusual to find a barrel where the bore is not perfectly in the centre of the barrel. Almost always the outside of the barrel is a circle, but should be able to measure in 6 or 8 places to confirm the diameters are the same. The release rim needs to be square and concentric to the bore - which is not necessarily to the outside of the barrel. A round barrel that is sawed off at an angle will look like an oval - that actually won't matter much so long as the last contact rim is square - makes for goofy looking muzzle, though, for sure!!! The hand crowning set that I got has a 90 degree cutter, so that makes a perfectly flat end to the barrel, at 90 degrees to the pilot - if pilot is a snug fit, that is close to the bore centreline. Then has an 11 degree cutter to make a "dished" shape muzzle, also off the pilot in the bore. Finally has a 45 degree cutter, also piloted, that we use to just take a tiny touch off ends of lands and very leading edges of the grooves to make that all "straight". Similar can be done on a lathe by pulling the barrel or having a mandrel to accept the barrelled receiver, chucking it up and indicating to zero off the bore (not the outside of the barrel) and then making similar cuts with lathe cutting tools. I have not done one on a lathe, although many others prefer to do it on a lathe instead of with hand tools. The key points are to be indicating off the bore, not the outside of the barrel, and to end up with a sharp, even release of the bullet.
 
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Sometimes "Bubba" can get a "good enough" muzzle by using lapping compound and a round headed brass ball or screw - Brownells even sells such a brass device. I have never used one to know if it works, if it works "as good as", or if it works dependably.
 
I don't think that barrel is crooked at all.

As for the crown, it looks to me like the false muzzle, drilled as a brake was cut off, along with the front sight.

You will have to duplicate the height of that front sight or you will keep experiencing the condition you're shooting now. No other fix.
 
Potashminer said:
I clicked the link in Post #8 - took me to a picture of a muzzle - not so sure about what I see - I was expecting to see lands and grooves right at the exact rim of the muzzle and the bore - you may have an opportunity there?? With a hand crowning tool and a pilot that fits snugly, it is a couple minutes to "square" and "sharpen" that edge. I am now doubting that can explain 5 feet high at 200 yards, unless part of a 8 foot to 10 foot diameter group at 200 yards??? Some militaries provided a "pull through" for cleaning - others provided a cleaning rod - sloppy use of either can result in the last bit of rifling in the bore, at the muzzle, being worn away by allowing the cleaning apparatus to rub against the rifling - was commonly addressed by "back boring" - I do not know if any militaries did that - essentially creating a new muzzle an inch or even two inches back inside the barrel, where the rifling is still good. I have never done that myself, but had a rifle that had that done to it.
Click to expand...


wait --- what? Feet? I read that as inches initially... we are talking five FEET too high?

After seeing your sight arrangement, I would shim it before finding a new sight.... head off to your local hobby shop most all of them sell brass and copper sheet stock up to 0.030 thick, $8-$10 ... make a few/several so you can swap them in and out to adjust the height at the range from the 40 to 60 thousandths (I think someone mentioned that range)

does it group at all?

looks like maybe all the barrel bands are gone, if I remember the AG42 had 2 action screws? they are both present and tight?
The gas system is still there? It looks like it, but I can't tell 100%.
The brake portion has been cut off... though I don't know if that can affect anything ...

I agree that crowning can't hurt it anymore, but also not sure that could explain five feet (!!)
 
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